BMJ 2016; 352 doi: http://dx.doi.org/10.1136/bmj.i582 (Published 08 March 2016)
Height, body mass index, and socioeconomic status: mendelian randomisation study in UK Biobank
Jessica Tyrrell, research fellow1 2, Samuel E Jones, associate research fellow1, Robin Beaumont, associate research fellow1, Christina M Astley, research fellow3 4, Rebecca Lovell, research fellow2, Hanieh Yaghootkar, research fellow1, Marcus Tuke, associate research fellow1, Katherine S Ruth, associate research fellow1, Rachel M Freathy, senior research fellow1, Joel N Hirschhorn, professor2 3 5, Andrew R Wood, research fellow1, Anna Murray, senior lecturer1, Michael N Weedon, associate professor1, Timothy M Frayling, professor1
Abstract
Objective To determine whether height and body mass index (BMI) have a causal role in five measures of socioeconomic status.
Design Mendelian randomisation study to test for causal effects of differences in stature and BMI on five measures of socioeconomic status. Mendelian randomisation exploits the fact that genotypes are randomly assigned at conception and thus not confounded by non-genetic factors.
Setting UK Biobank.
Participants 119 669 men and women of British ancestry, aged between 37 and 73 years.
Main outcome measures Age completed full time education, degree level education, job class, annual household income, and Townsend deprivation index.
Results In the UK Biobank study, shorter stature and higher BMI were observationally associated with several measures of lower socioeconomic status. The associations between shorter stature and lower socioeconomic status tended to be stronger in men, and the associations between higher BMI and lower socioeconomic status tended to be stronger in women. For example, a 1 standard deviation (SD) higher BMI was associated with a £210 (€276; $300; 95% confidence interval £84 to £420; P=6×10−3) lower annual household income in men and a £1890 (£1680 to £2100; P=6×10−15) lower annual household income in women. Genetic analysis provided evidence that these associations were partly causal. A genetically determined 1 SD (6.3 cm) taller stature caused a 0.06 (0.02 to 0.09) year older age of completing full time education (P=0.01), a 1.12 (1.07 to 1.18) times higher odds of working in a skilled profession (P=6×10−7), and a £1130 (£680 to £1580) higher annual household income (P=4×10−8). Associations were stronger in men. A genetically determined 1 SD higher BMI (4.6 kg/m2) caused a £2940 (£1680 to £4200; P=1×10−5) lower annual household income and a 0.10 (0.04 to 0.16) SD (P=0.001) higher level of deprivation in women only.
Conclusions These data support evidence that height and BMI play an important partial role in determining several aspects of a person’s socioeconomic status, especially women’s BMI for income and deprivation and men’s height for education, income, and job class. These findings have important social and health implications, supporting evidence that overweight people, especially women, are at a disadvantage and that taller people, especially men, are at an advantage.
Link
Showing posts with label Body type. Show all posts
Showing posts with label Body type. Show all posts
March 09, 2016
April 23, 2014
Neandertal populations were small (+ differences along the Neandertal/sapiens evolutionary lineages)
PNAS doi: 10.1073/pnas.1405138111
Patterns of coding variation in the complete exomes of three Neandertals
Sergi Castellano et al.
We present the DNA sequence of 17,367 protein-coding genes in two Neandertals from Spain and Croatia and analyze them together with the genome sequence recently determined from a Neandertal from southern Siberia. Comparisons with present-day humans from Africa, Europe, and Asia reveal that genetic diversity among Neandertals was remarkably low, and that they carried a higher proportion of amino acid-changing (nonsynonymous) alleles inferred to alter protein structure or function than present-day humans. Thus, Neandertals across Eurasia had a smaller long-term effective population than present-day humans. We also identify amino acid substitutions in Neandertals and present-day humans that may underlie phenotypic differences between the two groups. We find that genes involved in skeletal morphology have changed more in the lineage leading to Neandertals than in the ancestral lineage common to archaic and modern humans, whereas genes involved in behavior and pigmentation have changed more on the modern human lineage.
Link
Patterns of coding variation in the complete exomes of three Neandertals
Sergi Castellano et al.
We present the DNA sequence of 17,367 protein-coding genes in two Neandertals from Spain and Croatia and analyze them together with the genome sequence recently determined from a Neandertal from southern Siberia. Comparisons with present-day humans from Africa, Europe, and Asia reveal that genetic diversity among Neandertals was remarkably low, and that they carried a higher proportion of amino acid-changing (nonsynonymous) alleles inferred to alter protein structure or function than present-day humans. Thus, Neandertals across Eurasia had a smaller long-term effective population than present-day humans. We also identify amino acid substitutions in Neandertals and present-day humans that may underlie phenotypic differences between the two groups. We find that genes involved in skeletal morphology have changed more in the lineage leading to Neandertals than in the ancestral lineage common to archaic and modern humans, whereas genes involved in behavior and pigmentation have changed more on the modern human lineage.
Link
March 05, 2013
Extreme mobility in the late Pleistocene (Shaw and Stock 2013)
Journal of Human Evolution doi:10.1016/j.jhevol.2013.01.004
Extreme mobility in the Late Pleistocene? Comparing limb biomechanics among fossil Homo, varsity athletes and Holocene foragers
Colin N. Shaw, Jay T. Stock
Descriptions of Pleistocene activity patterns often derive from comparisons of long bone diaphyseal robusticity across contemporaneous fossilized hominins. The purpose of this study is to augment existing understanding of Pleistocene hominin mobility patterns by interpreting fossil variation through comparisons with a) living human athletes with known activity patterns, and b) Holocene foragers where descriptions of group-level activity patterns are available. Relative tibial rigidity (midshaft tibial rigidity (J)/midshaft humeral rigidity (J)) was compared amongst Levantine and European Neandertals, Levantine and Upper Palaeolithic Homo sapiens, Holocene foragers and living human athletes and controls. Cross-country runners exhibit significantly (p < 0.05) greater relative tibial rigidity compared with swimmers, and higher values compared with controls. In contrast, swimmers displayed significantly (p < 0.05) lower relative tibial rigidity than both runners and controls. While variation exists among all Holocene H. sapiens, highly terrestrially mobile Later Stone Age (LSA) southern Africans and cross-country runners display the highest relative tibial rigidity, while maritime Andaman Islanders and swimmers display the lowest, with controls falling between. All fossil hominins displayed relative tibial rigidity that exceeded, or was similar to, the highly terrestrially mobile Later Stone Age southern Africans and modern human cross-country runners. The more extreme skeletal structure of most Neandertals and Levantine H. sapiens, as well as the odd Upper Palaeolithic individual, appears to reflect adaptation to intense and/or highly repetitive lower limb (relative to upper limb) loading. This loading may have been associated with bipedal travel, and appears to have been more strenuous than that encountered by even university varsity runners, and Holocene foragers with hunting grounds 2000–3000 square miles in size. Skeletal variation among the athletes and foraging groups is consistent with known or inferred activity profiles, which support the position that the Pleistocene remains reflect adaptation to extremely active and mobile lives.
Link
January 03, 2013
Body form variation of prehistoric Jomon (Fukase et al. 2012)
Am J Phys Anthropol DOI: 10.1002/ajpa.22112
Geographic variation in body form of prehistoric Jomon males in the Japanese archipelago: Its ecogeographic implications
Hitoshi Fukase et al.
Diversity of human body size and shape is often biogeographically interpreted in association with climatic conditions. According to Bergmann's and Allen's rules, populations in regions with a cold climate are expected to display an overall larger body and smaller/shorter extremities than those in warm/hot environments. In the present study, the skeletal limb size and proportions of prehistoric Jomon hunter-gatherers, who extensively inhabited subarctic to subtropical areas in the ancient Japanese archipelago, were examined to evaluate whether or not the inter-regional differences follow such ecogeographic patterns. Results showed that the Jomon intralimb proportions including relative distal limb lengths did not differ significantly among five regions from northern Hokkaido to the southern Okinawa Islands. This suggests a limited co-variability of the intralimb proportions with climate, particularly within genealogically close populations. In contrast, femoral head breadth (associated with body mass) and skeletal limb lengths were found to be significantly and positively correlated with latitude, suggesting a north-south geographical cline in the body size. This gradient therefore comprehensively conforms to Bergmann's rule, and may stem from multiple potential factors such as phylogenetic constraints, microevolutionary adaptation to climatic/geographic conditions during the Jomon period, and nutritional and physiological response during ontogeny. Specifically, the remarkably small-bodied Jomon in the Okinawa Islands can also be explained as an adjustment to subtropical and insular environments. Thus, the findings obtained in this study indicate that Jomon people, while maintaining fundamental intralimb proportions, displayed body size variation in concert with ambient surroundings.
Link
Geographic variation in body form of prehistoric Jomon males in the Japanese archipelago: Its ecogeographic implications
Hitoshi Fukase et al.
Diversity of human body size and shape is often biogeographically interpreted in association with climatic conditions. According to Bergmann's and Allen's rules, populations in regions with a cold climate are expected to display an overall larger body and smaller/shorter extremities than those in warm/hot environments. In the present study, the skeletal limb size and proportions of prehistoric Jomon hunter-gatherers, who extensively inhabited subarctic to subtropical areas in the ancient Japanese archipelago, were examined to evaluate whether or not the inter-regional differences follow such ecogeographic patterns. Results showed that the Jomon intralimb proportions including relative distal limb lengths did not differ significantly among five regions from northern Hokkaido to the southern Okinawa Islands. This suggests a limited co-variability of the intralimb proportions with climate, particularly within genealogically close populations. In contrast, femoral head breadth (associated with body mass) and skeletal limb lengths were found to be significantly and positively correlated with latitude, suggesting a north-south geographical cline in the body size. This gradient therefore comprehensively conforms to Bergmann's rule, and may stem from multiple potential factors such as phylogenetic constraints, microevolutionary adaptation to climatic/geographic conditions during the Jomon period, and nutritional and physiological response during ontogeny. Specifically, the remarkably small-bodied Jomon in the Okinawa Islands can also be explained as an adjustment to subtropical and insular environments. Thus, the findings obtained in this study indicate that Jomon people, while maintaining fundamental intralimb proportions, displayed body size variation in concert with ambient surroundings.
Link
December 02, 2012
Quantifying an attractive body
The figures on the left (A and B) were set by female participants, and on the right (C and D) by male ones. There is not much that is surprising in the paper, but here's an interesting finding:
An alternative explanation would be that the ideals are influenced by a common media environment which pushes them towards the same concept of the ideal body. However, there are subtle gender-specific differences in the media images seen in the magazines targeted at men and women. For the male body, magazines aimed at a male audience contain male models which are more muscular than those aimed at a female audience [31], [66]. For the female body, female models in women’s magazines are slimmer and have a smaller bust than female models in men’s magazines [53], [54]. This would suggest that there should be systematic differences between the ideals favoured by the two genders.
This is partially what we find here. The male body selected by the male participants is indeed more muscular than the ideal male body chosen by the female participants. However, in the case of the ideal female body both men and women prefer a female body with the same low BMI, but the female participants prefer a larger bust size than the male participants. This directly contradicts what would be expected from the size and shape of the female models in their respective gender-specific media; the men should prefer a heavier female body than the women and a larger bust.
It might be interesting to repeat this experiment in a non-British sample as well as a sample that is not influenced by media. Anyone have an explanation to offer?
PLoS ONE 7(11): e50601. doi:10.1371/journal.pone.0050601
What Is an Attractive Body? Using an Interactive 3D Program to Create the Ideal Body for You and Your Partner
Kara L. Crossley
What is the ideal body size and shape that we want for ourselves and our partners? What are the important physical features in this ideal? And do both genders agree on what is an attractive body? To answer these questions we used a 3D interactive software system which allows our participants to produce a photorealistic, virtual male or female body. Forty female and forty male heterosexual Caucasian observers (females mean age 19.10 years, s.d. 1.01; 40 males mean age 19.84, s.d. 1.66) set their own ideal size and shape, and the size and shape of their ideal partner using the DAZ studio image manipulation programme. In this programme the shape and size of a 3D body can be altered along 94 independent dimensions, allowing each participant to create the exact size and shape of the body they want. The volume (and thus the weight assuming a standard density) and the circumference of the bust, waist and hips of these 3D models can then be measured. The ideal female body set by women (BMI = 18.9, WHR = 0.70, WCR = 0.67) was very similar to the ideal partner set by men, particularly in their BMI (BMI = 18.8, WHR = 0.73, WCR = 0.69). This was a lower BMI than the actual BMI of 39 of the 40 women. The ideal male body set by the men (BMI = 25.9, WHR = 0.87, WCR = 0.74) was very similar to the ideal partner set by the women (BMI = 24.5, WHR = 0.86, WCR = 0.77). This was a lower BMI than the actual BMI of roughly half of the men and a higher BMI than the other half. The results suggest a consistent preference for an ideal male and female body size and shape across both genders. The results also suggest that both BMI and torso shape are important components for the creation of the ideal body.
Link
October 25, 2012
Wide-bodied early Holocene north Americans
Am J Phys Anthropol DOI: 10.1002/ajpa.22154
Skeletal variation among early holocene north american humans: Implications for origins and diversity in the americas
Benjamin M. Auerbach
The movement of humans into the Americas remains a major topic of debate among scientific disciplines. Central to this discussion is ascertaining the timing and migratory routes of the earliest colonizers, in addition to understanding their ancestry. Molecular studies have recently argued that the colonizing population was isolated from other Asian populations for an extended period before proceeding to colonize the Americas. This research has suggested that Beringia was the location of this “incubation,” though archaeological and skeletal data have not yet supported this hypothesis. This study employs the remains of the five most complete North American male early Holocene skeletons to examine patterns of human morphology at the earliest observable time period. Stature, body mass, body breadth, and limb proportions are examined in the context of male skeletal samples representing the range of morphological variation in North America in the last two millennia of the Holocene. These are also compared with a global sample. Results indicate that early Holocene males have variable postcranial morphologies, but all share the common trait of wide bodies. This trait, which is retained in more recent indigenous North American groups, is associated with adaptations to cold climates. Peoples from the Americas exhibit wider bodies than other populations sampled globally. This pattern suggests the common ancestral population of all of these indigenous American groups had reduced morphological variation in this trait. Furthermore, this provides support for a single, possibly high latitude location for the genetic isolation of ancestors of the human colonizers of the Americas.
Link
Skeletal variation among early holocene north american humans: Implications for origins and diversity in the americas
Benjamin M. Auerbach
The movement of humans into the Americas remains a major topic of debate among scientific disciplines. Central to this discussion is ascertaining the timing and migratory routes of the earliest colonizers, in addition to understanding their ancestry. Molecular studies have recently argued that the colonizing population was isolated from other Asian populations for an extended period before proceeding to colonize the Americas. This research has suggested that Beringia was the location of this “incubation,” though archaeological and skeletal data have not yet supported this hypothesis. This study employs the remains of the five most complete North American male early Holocene skeletons to examine patterns of human morphology at the earliest observable time period. Stature, body mass, body breadth, and limb proportions are examined in the context of male skeletal samples representing the range of morphological variation in North America in the last two millennia of the Holocene. These are also compared with a global sample. Results indicate that early Holocene males have variable postcranial morphologies, but all share the common trait of wide bodies. This trait, which is retained in more recent indigenous North American groups, is associated with adaptations to cold climates. Peoples from the Americas exhibit wider bodies than other populations sampled globally. This pattern suggests the common ancestral population of all of these indigenous American groups had reduced morphological variation in this trait. Furthermore, this provides support for a single, possibly high latitude location for the genetic isolation of ancestors of the human colonizers of the Americas.
Link
January 09, 2012
Neandertal shoulder blades and the direction of gene flow
John Hawks points me to a new paper by Di Vicenzo et al. What is most interesting to me is the following figure:
What is most striking about it is the position of Vindija, an Upper Paleolithic Neandertal specimen which is clearly closer to Homo sapiens specimens than any of the Neandertal or archaic humans.
The first component is one of increasing (left-to-right) modernity, with Australopithecus on the left, and modern humans on the right. Apart from Vindija, the two West Asian samples from Kebara and Shanidar also appear quite "modern" in terms of their component 1 position.
There are two possible options: that Neandertals and modern humans were evolving in parallel towards a "modern" scapular glenoid fossa shape; or, that these Neandertals may have experienced gene flow from modern humans.
I am inclined to accept the idea of gene flow: Kebara and Shanidar are from the time when genetic evidence suggests that the major expansion of modern humans was well under way, and Vindija from a time when they had most probably already arrived in Europe. If there was AMH-to-Neandertal gene flow, these are exactly the Neandertal specimens that might be affected, and not, e.g., the >100ka European Neandertals that can be safely assumed to lack any modern human ancestry on a variety of grounds.
Dr. Hawks writes:
I remain skeptical about the mainstream story about what this involvement is (Neandertal-to-Eurasian gene flow), and this analysis certainly seems consistent with the alternative (AMH-to-Neandertal gene flow during the expansion of modern humans out of the Near East). I can definitely co-sign the following statement by Dr. Hawks:
The scenario of gene flow from the paper can be seen below:
I want to highlight a couple of facts:
In the Levant, Tabun (120ky) is less modern than Kebara (60ky). This is exactly as we expect if there was a major human expansion c. 70ky, as I have argued for in my blog post on L3 and here. The same difference between Krapina (130ky) and Vindija (40ky), the latter just at the time when modern humans were getting there.
Notice also how "natural" Out-of-Arabia fits with the rest of the scenario: a group of expanding humans from Arabia (south-to-north) forms a natural extension that would affect Kebara, Shanidar, and ultimately Vindija. I won't even bother with the Coastal Migration Theory that seems utterly unable to explain modern-Neandertal interbreeding.
Journal of Human Evolution
The Vindija Neanderthal scapular glenoid fossa: Comparative shape analysis suggests evo-devo changes among Neanderthals
Fabio Di Vincenzo et al.
Although the shape of the scapular glenoid fossa (SGF) may be influenced by epigenetic and developmental factors, there appears to be strong genetic control over its overall form, such that variation within and between hominin taxa in SGF shape may contain information about their evolutionary histories. Here we present the results of a geometric morphometric study of the SGF of the Neanderthal Vi-209 from Vindjia Cave (Croatia), relative to samples of Plio-Pleistocene, later Pleistocene, and recent hominins. Variation in overall SGF shape follows a chronological trend from the plesiomorphic condition seen in Australopithecus to modern humans, with pre-modern species of the genus Homo exhibiting intermediate morphologies. Change in body size across this temporal series is not linearly directional, which argues against static allometry as an explanation. However, life history and developmental rates change directionally across the series, suggesting an ontogenetic effect on the observed changes in shape (ontogenetic allometry). Within this framework, the morphospace occupied by the Neanderthals exhibits a discontinuous distribution. The Vindija SGF and those of the later Near Eastern Neanderthals (Kebara and Shanidar) approach the modern condition and are somewhat segregated from both northwestern European (Neandertal and La Ferrassie) and early Mediterranean Neanderthals (Krapina and Tabun). Although more than one scenario may account for the pattern seen in the Neanderthals, the data is consistent with palaeogenetic evidence suggesting low levels of gene flow between Neanderthals and modern humans in the Near East after ca. 120–100 ka (thousands of years ago) (with subsequent introgression of modern human alleles into eastern and central Europe). Thus, in keeping with previous analyses that document some modern human features in the Vindija Neanderthals, the Vindija G3 sample should not be seen as representative of ‘classic’ – that is, unadmixed, pre-contact – Neanderthal morphology.
Link
What is most striking about it is the position of Vindija, an Upper Paleolithic Neandertal specimen which is clearly closer to Homo sapiens specimens than any of the Neandertal or archaic humans.
The first component is one of increasing (left-to-right) modernity, with Australopithecus on the left, and modern humans on the right. Apart from Vindija, the two West Asian samples from Kebara and Shanidar also appear quite "modern" in terms of their component 1 position.
There are two possible options: that Neandertals and modern humans were evolving in parallel towards a "modern" scapular glenoid fossa shape; or, that these Neandertals may have experienced gene flow from modern humans.
I am inclined to accept the idea of gene flow: Kebara and Shanidar are from the time when genetic evidence suggests that the major expansion of modern humans was well under way, and Vindija from a time when they had most probably already arrived in Europe. If there was AMH-to-Neandertal gene flow, these are exactly the Neandertal specimens that might be affected, and not, e.g., the >100ka European Neandertals that can be safely assumed to lack any modern human ancestry on a variety of grounds.
Dr. Hawks writes:
There is as yet no evidence that the Vindija Neandertal genomes have genetic introgression from the African populations from which present non-Africans derive most of their genetic heritage. Green and colleagues [4] tested explicitly for this kind of gene flow, from "modern" into Neandertal populations and found none.I am not convinced by the strength of that test, as it is based on the assumption that modern-to-Neandertal gene flow would Eurasianize the sequence we got from Vindija. That assumption is not secure, since:
- It seems increasingly likely that the major Upper Paleolithic expansion of humans originated in Asia and not in Africa, in which case the expanding moderns would be Proto-Human rather than Proto-Eurasian
- We've now had enough contrasts between Mesolithic/Neolithic and present-day DNA to cure us of the illusion that populations are largely static: we simply have no evidence (until we actually test them) as to what early modern humans in the Near East and Europe were like genetically.
I remain skeptical about the mainstream story about what this involvement is (Neandertal-to-Eurasian gene flow), and this analysis certainly seems consistent with the alternative (AMH-to-Neandertal gene flow during the expansion of modern humans out of the Near East). I can definitely co-sign the following statement by Dr. Hawks:
Frankly, I expect that the admixture estimates presented thus far will prove to be wrong. I could be wrong in this expectation, but there are many assumptions underlying genetic analyses of admixture, and it's easy for an incorrect assumption to give rise to an incorrect conclusion. I take the morphological evidence very seriously as a possible "reality-check" about the validity of genetic comparisons. After all, the morphological comparisons predicted introgression from Neandertals in the first place...UPDATE:
The scenario of gene flow from the paper can be seen below:
I want to highlight a couple of facts:
In the Levant, Tabun (120ky) is less modern than Kebara (60ky). This is exactly as we expect if there was a major human expansion c. 70ky, as I have argued for in my blog post on L3 and here. The same difference between Krapina (130ky) and Vindija (40ky), the latter just at the time when modern humans were getting there.
Notice also how "natural" Out-of-Arabia fits with the rest of the scenario: a group of expanding humans from Arabia (south-to-north) forms a natural extension that would affect Kebara, Shanidar, and ultimately Vindija. I won't even bother with the Coastal Migration Theory that seems utterly unable to explain modern-Neandertal interbreeding.
Journal of Human Evolution
The Vindija Neanderthal scapular glenoid fossa: Comparative shape analysis suggests evo-devo changes among Neanderthals
Fabio Di Vincenzo et al.
Although the shape of the scapular glenoid fossa (SGF) may be influenced by epigenetic and developmental factors, there appears to be strong genetic control over its overall form, such that variation within and between hominin taxa in SGF shape may contain information about their evolutionary histories. Here we present the results of a geometric morphometric study of the SGF of the Neanderthal Vi-209 from Vindjia Cave (Croatia), relative to samples of Plio-Pleistocene, later Pleistocene, and recent hominins. Variation in overall SGF shape follows a chronological trend from the plesiomorphic condition seen in Australopithecus to modern humans, with pre-modern species of the genus Homo exhibiting intermediate morphologies. Change in body size across this temporal series is not linearly directional, which argues against static allometry as an explanation. However, life history and developmental rates change directionally across the series, suggesting an ontogenetic effect on the observed changes in shape (ontogenetic allometry). Within this framework, the morphospace occupied by the Neanderthals exhibits a discontinuous distribution. The Vindija SGF and those of the later Near Eastern Neanderthals (Kebara and Shanidar) approach the modern condition and are somewhat segregated from both northwestern European (Neandertal and La Ferrassie) and early Mediterranean Neanderthals (Krapina and Tabun). Although more than one scenario may account for the pattern seen in the Neanderthals, the data is consistent with palaeogenetic evidence suggesting low levels of gene flow between Neanderthals and modern humans in the Near East after ca. 120–100 ka (thousands of years ago) (with subsequent introgression of modern human alleles into eastern and central Europe). Thus, in keeping with previous analyses that document some modern human features in the Vindija Neanderthals, the Vindija G3 sample should not be seen as representative of ‘classic’ – that is, unadmixed, pre-contact – Neanderthal morphology.
Link
January 02, 2012
Activity patterns of Garamantes
A different paper on cranial nonmetric traits from the same team and on the same population (Garamantes).
From the current paper:
AJPA DOI: 10.1002/ajpa.21597
Activity patterns in the Sahara Desert: An interpretation based on cross-sectional geometric properties
Efthymia Nikita et al.
The Garamantian civilization flourished in modern Fezzan, Libya, between 900 BC and 500 AD, during which the aridification of the Sahara was well established. Study of the archaeological remains suggests a population successful at coping with a harsh environment of high and fluctuating temperatures and reduced water and food resources. This study explores the activity patterns of the Garamantes by means of cross-sectional geometric properties. Long bone diaphyseal shape and rigidity are compared between the Garamantes and populations from Egypt and Sudan, namely from the sites of Kerma, el-Badari, and Jebel Moya, to determine whether the Garamantian daily activities were more strenuous than those of other North African populations. Moreover, sexual dimorphism and bilateral asymmetry are assessed at an intra- and inter-population level. The inter-population comparisons showed the Garamantes not to be more robust than the comparative populations, suggesting that the daily Garamantian activities necessary for survival in the Sahara Desert did not generally impose greater loads than those of other North African populations. Sexual dimorphism and bilateral asymmetry in almost all geometric properties of the long limbs were comparatively low among the Garamantes. Only the lower limbs were significantly stronger among males than females, possibly due to higher levels of mobility associated with herding. The lack of systematic bilateral asymmetry in cross-sectional geometric properties may relate to the involvement of the population in bilaterally intensive activities or the lack of regular repetition of unilateral activities.
Link
From the current paper:
The study of the activity patterns of the Garamantes, a population that flourished at Central Sahara approximately 3,000 years ago, offers some interesting insights on the levels of stress imposed by a sedentary life in a hyper-arid environment. The population showed low bilateral asymmetry, possibly due to limited task specialization. Moreover, the Garamantes exhibited low sexual dimorphism in the upper limbs, which is consistent to the pattern found in agricultural populations and implies that the engagement of males in warfare and construction works was not particularly intense. In the lower limbs, males were stronger in TA possibly as a result of their involvement in herding and mobility on the uneven terrain of Fezzan. Finally, the Garamantes did not appear systematically more robust than other North African populations occupying less harsh environments, indicating that life in the Sahara did not require particularly strenuous daily activities.
AJPA DOI: 10.1002/ajpa.21597
Activity patterns in the Sahara Desert: An interpretation based on cross-sectional geometric properties
Efthymia Nikita et al.
The Garamantian civilization flourished in modern Fezzan, Libya, between 900 BC and 500 AD, during which the aridification of the Sahara was well established. Study of the archaeological remains suggests a population successful at coping with a harsh environment of high and fluctuating temperatures and reduced water and food resources. This study explores the activity patterns of the Garamantes by means of cross-sectional geometric properties. Long bone diaphyseal shape and rigidity are compared between the Garamantes and populations from Egypt and Sudan, namely from the sites of Kerma, el-Badari, and Jebel Moya, to determine whether the Garamantian daily activities were more strenuous than those of other North African populations. Moreover, sexual dimorphism and bilateral asymmetry are assessed at an intra- and inter-population level. The inter-population comparisons showed the Garamantes not to be more robust than the comparative populations, suggesting that the daily Garamantian activities necessary for survival in the Sahara Desert did not generally impose greater loads than those of other North African populations. Sexual dimorphism and bilateral asymmetry in almost all geometric properties of the long limbs were comparatively low among the Garamantes. Only the lower limbs were significantly stronger among males than females, possibly due to higher levels of mobility associated with herding. The lack of systematic bilateral asymmetry in cross-sectional geometric properties may relate to the involvement of the population in bilaterally intensive activities or the lack of regular repetition of unilateral activities.
Link
December 30, 2011
Climate and body composition
Am J Phys Anthropol DOI: 10.1002/ajpa.21591
Ecogeographical associations between climate and human body composition: Analyses based on anthropometry and skinfolds
Jonathan C.K. Wells et al.
Abstract
In the 19th century, two “ecogeographical rules” were proposed hypothesizing associations of climate with mammalian body size and proportions. Data on human body weight and relative leg length support these rules; however, it is unknown whether such associations are attributable to lean tissue (the heat-producing component) or fat (energy stores). Data on weight, height, and two skinfold thickness were obtained from the literature for 137 nonindustrialized populations, providing 145 male and 115 female individual samples. A variety of indices of adiposity and lean mass were analyzed. Preliminary analyses indicated secular increases in skinfolds in men but not women, and associations of age and height with lean mass in both sexes. Decreasing annual temperature was associated with increasing body mass index (BMI), and increasing triceps but not subscapular skinfold. After adjusting for skinfolds, decreasing temperature remained associated with increasing BMI. These results indicate that colder environments favor both greater peripheral energy stores, and greater lean mass. Contrasting results for triceps and subscapular skinfolds might be due to adaptive strategies either constraining central adiposity in cold environments to reduce cardiovascular risk, or favoring central adiposity in warmer environments to maintain energetic support of the immune system. Polynesian populations were analyzed separately and contradicted all of the climate trends, indicating support for the hypothesis that they are cold-adapted despite occupying a tropical region. It is unclear whether such associations emerge through natural selection or through trans-generational and life-course plasticity. These findings nevertheless aid understanding of the wide variability in human physique and adiposity.
Link
Ecogeographical associations between climate and human body composition: Analyses based on anthropometry and skinfolds
Jonathan C.K. Wells et al.
Abstract
In the 19th century, two “ecogeographical rules” were proposed hypothesizing associations of climate with mammalian body size and proportions. Data on human body weight and relative leg length support these rules; however, it is unknown whether such associations are attributable to lean tissue (the heat-producing component) or fat (energy stores). Data on weight, height, and two skinfold thickness were obtained from the literature for 137 nonindustrialized populations, providing 145 male and 115 female individual samples. A variety of indices of adiposity and lean mass were analyzed. Preliminary analyses indicated secular increases in skinfolds in men but not women, and associations of age and height with lean mass in both sexes. Decreasing annual temperature was associated with increasing body mass index (BMI), and increasing triceps but not subscapular skinfold. After adjusting for skinfolds, decreasing temperature remained associated with increasing BMI. These results indicate that colder environments favor both greater peripheral energy stores, and greater lean mass. Contrasting results for triceps and subscapular skinfolds might be due to adaptive strategies either constraining central adiposity in cold environments to reduce cardiovascular risk, or favoring central adiposity in warmer environments to maintain energetic support of the immune system. Polynesian populations were analyzed separately and contradicted all of the climate trends, indicating support for the hypothesis that they are cold-adapted despite occupying a tropical region. It is unclear whether such associations emerge through natural selection or through trans-generational and life-course plasticity. These findings nevertheless aid understanding of the wide variability in human physique and adiposity.
Link
November 09, 2011
To survive: be fat or be smart
The bottom line is that it makes sense for an animal to combine the "fat" and "smart" strategies to survive. It makes sense: a very fat but very dumb animal has all the energy reserves it will ever need, but at the expense of locomotion efficiency, avoidance of predators, etc. A very smart but very lean animal has all the brain power needed to survive, but has very little "in the tank" if it finds itself in a bad spot and has to go without food for a long time.
The versatile strategy is best, and humans are the one species that seems to have gone the "brain power" way, without sacrificing completely other traits needed for survival.
Nature (2011) doi:10.1038/nature10629
Energetics and the evolution of human brain size
Ana Navarrete et al.
The human brain stands out among mammals by being unusually large. The expensive-tissue hypothesis1 explains its evolution by proposing a trade-off between the size of the brain and that of the digestive tract, which is smaller than expected for a primate of our body size. Although this hypothesis is widely accepted, empirical support so far has been equivocal. Here we test it in a sample of 100 mammalian species, including 23 primates, by analysing brain size and organ mass data. We found that, controlling for fat-free body mass, brain size is not negatively correlated with the mass of the digestive tract or any other expensive organ, thus refuting the expensive-tissue hypothesis. Nonetheless, consistent with the existence of energy trade-offs with brain size, we find that the size of brains and adipose depots are negatively correlated in mammals, indicating that encephalization and fat storage are compensatory strategies to buffer against starvation. However, these two strategies can be combined if fat storage does not unduly hamper locomotor efficiency. We propose that human encephalization was made possible by a combination of stabilization of energy inputs and a redirection of energy from locomotion, growth and reproduction.
Link
The versatile strategy is best, and humans are the one species that seems to have gone the "brain power" way, without sacrificing completely other traits needed for survival.
Nature (2011) doi:10.1038/nature10629
Energetics and the evolution of human brain size
Ana Navarrete et al.
The human brain stands out among mammals by being unusually large. The expensive-tissue hypothesis1 explains its evolution by proposing a trade-off between the size of the brain and that of the digestive tract, which is smaller than expected for a primate of our body size. Although this hypothesis is widely accepted, empirical support so far has been equivocal. Here we test it in a sample of 100 mammalian species, including 23 primates, by analysing brain size and organ mass data. We found that, controlling for fat-free body mass, brain size is not negatively correlated with the mass of the digestive tract or any other expensive organ, thus refuting the expensive-tissue hypothesis. Nonetheless, consistent with the existence of energy trade-offs with brain size, we find that the size of brains and adipose depots are negatively correlated in mammals, indicating that encephalization and fat storage are compensatory strategies to buffer against starvation. However, these two strategies can be combined if fat storage does not unduly hamper locomotor efficiency. We propose that human encephalization was made possible by a combination of stabilization of energy inputs and a redirection of energy from locomotion, growth and reproduction.
Link
October 01, 2011
Secular trends in some Russian populations
Anthropol Anz. 2011;68(4):367-77.
Secular trends in some Russian populations.
Godina EZ
Abstract
Secular changes of body measurements in children have been the subject of studies in many different countries. In recent years, there has been an increase in BMI associated with a significant trend towards obesity in both Europe and the US. The aim of the present study was to analyze trends in body measurements and BMI in Russia from the 1960's to the beginning of the 21st century. This was done at three locations of the Russian Federation: the city of Moscow, the cities of Saratov and Naberezhnye Chelny in the Volga-river area. In addition, data on secular changes of Abkhazian children were analyzed. A large number of anthropometric measurements were taken on each individual including height, weight, arm, leg and trunk lengths (estimated), body diameters and circumferences, skinfold thickness, head and face dimensions. Stages of secondary sex characteristics also were evaluated; data on menarcheal age were collected by status-quo and retrospective methods. Changes in hand grip strength have been evaluated in some of the samples. While stature was increasing during these years, weight, chest circumference and BMI were characterized by negative changes, which became more obvious in elder girls. Changes in handgrip strength also showed negative trends. There were noticeable changes in head and face measurements, which were expressed in more elongated head and face forms, i.e. the head became longer and narrower with narrower and higher faces. Secular changes in head and facial morphology may be considered part of the general trend.
Link
Secular trends in some Russian populations.
Godina EZ
Abstract
Secular changes of body measurements in children have been the subject of studies in many different countries. In recent years, there has been an increase in BMI associated with a significant trend towards obesity in both Europe and the US. The aim of the present study was to analyze trends in body measurements and BMI in Russia from the 1960's to the beginning of the 21st century. This was done at three locations of the Russian Federation: the city of Moscow, the cities of Saratov and Naberezhnye Chelny in the Volga-river area. In addition, data on secular changes of Abkhazian children were analyzed. A large number of anthropometric measurements were taken on each individual including height, weight, arm, leg and trunk lengths (estimated), body diameters and circumferences, skinfold thickness, head and face dimensions. Stages of secondary sex characteristics also were evaluated; data on menarcheal age were collected by status-quo and retrospective methods. Changes in hand grip strength have been evaluated in some of the samples. While stature was increasing during these years, weight, chest circumference and BMI were characterized by negative changes, which became more obvious in elder girls. Changes in handgrip strength also showed negative trends. There were noticeable changes in head and face measurements, which were expressed in more elongated head and face forms, i.e. the head became longer and narrower with narrower and higher faces. Secular changes in head and facial morphology may be considered part of the general trend.
Link
September 09, 2009
Reduced fecundity of fat women
J Womens Health (Larchmt). 2009 May;18(5):633-6.
The relationship between obesity and fecundity.
Yilmaz N, Kilic S, Kanat-Pektas M, Gulerman C, Mollamahmutoglu L.
OBJECTIVE: Obesity is an important factor that might reduce fecundity. In order to determine the underlying physiological mechanisms and risk factors, the obesity-fecundity association is investigated in relation to parity, menstrual cycle regularity, smoking habits, and age. METHODS: This was a retrospective cohort study of 22,840 women who gave birth between January 2006 and January 2007 in the Dr Zekai Tahir Burak Women's Health Research and Education Hospital. Age, parity, prepregnancy body mass index (BMI) values, time to pregnancy data related to smoking, and reproductive, medical, and gynecological history were obtained from the medical records. RESULTS: Fecundity was reduced for overweight and obese women compared with optimal weight women, and this reduction was more evident for obese primiparous women. Fecundity remained reduced for overweight and obese women with normal menstrual cycles. Obese and overweight women were found to smoke significantly more than the optimal weight group. CONCLUSIONS: Obesity was found to be associated with reduced fecundity for all weight-adjusted groups of women and persisted for women with regular cycles. Weight loss should be encouraged initially during the treatment of infertile overweight and obese women.
Link
The relationship between obesity and fecundity.
Yilmaz N, Kilic S, Kanat-Pektas M, Gulerman C, Mollamahmutoglu L.
OBJECTIVE: Obesity is an important factor that might reduce fecundity. In order to determine the underlying physiological mechanisms and risk factors, the obesity-fecundity association is investigated in relation to parity, menstrual cycle regularity, smoking habits, and age. METHODS: This was a retrospective cohort study of 22,840 women who gave birth between January 2006 and January 2007 in the Dr Zekai Tahir Burak Women's Health Research and Education Hospital. Age, parity, prepregnancy body mass index (BMI) values, time to pregnancy data related to smoking, and reproductive, medical, and gynecological history were obtained from the medical records. RESULTS: Fecundity was reduced for overweight and obese women compared with optimal weight women, and this reduction was more evident for obese primiparous women. Fecundity remained reduced for overweight and obese women with normal menstrual cycles. Obese and overweight women were found to smoke significantly more than the optimal weight group. CONCLUSIONS: Obesity was found to be associated with reduced fecundity for all weight-adjusted groups of women and persisted for women with regular cycles. Weight loss should be encouraged initially during the treatment of infertile overweight and obese women.
Link
September 07, 2009
European admixture and obesity traits in African Americans
Obesity (Silver Spring). doi:10.1038/oby.2009.282
Admixture Mapping of Obesity-related Traits in African Americans: The Atherosclerosis Risk in Communities (ARIC) Study.
Cheng CY, Reich D, Coresh J, Boerwinkle E, Patterson N, Li M, North KE, Tandon A, Bailey-Wilson JE, Wilson JG, Kao WH.
Obesity is an important cause of morbidity and mortality worldwide. In the United States, the prevalence of obesity is higher in African Americans than whites, even after adjustment for socioeconomic status (SES). This leads to the hypothesis that differences in genetic background may contribute to racial/ethnic differences in obesity-related traits. We tested this hypothesis by conducting a genome-wide admixture mapping scan using 1,350 ancestry-informative single-nucleotide polymorphisms (SNPs) in 3,531 self-identified blacks from the Atherosclerosis Risk in Communities (ARIC) study. We used these markers to estimate the overall proportions of European ancestry (PEAs) for each individual and then scanned for the association between PEA and obesity-related traits (both continuous and dichotomous) at each locus. The median (interquartile range) PEA was 0.151 (0.115). PEA was inversely correlated with continuous BMI, weight, and subscapular skinfold thickness, even after adjusting for socioeconomic factors. In contrast, PEA was positively correlated with BMI-adjusted waist circumference. Using admixture mapping on dichotomized traits, we identified a locus on 2p23.3 to be suggestively associated with BMI (locus-specific lod = 4.11) and weight (locus-specific lod = 4.07). After adjusting for global PEA, each additional copy of a European ancestral allele at the 2p23.3 peak was associated with a BMI decrease of ~0.92 kg/m(2) (P = 2.9 x 10(-5)). Further mapping in this region on chromosome 2 may be able to uncover causative variants underlying obesity, which may offer insights into the control of energy homeostasis.
Link
Admixture Mapping of Obesity-related Traits in African Americans: The Atherosclerosis Risk in Communities (ARIC) Study.
Cheng CY, Reich D, Coresh J, Boerwinkle E, Patterson N, Li M, North KE, Tandon A, Bailey-Wilson JE, Wilson JG, Kao WH.
Obesity is an important cause of morbidity and mortality worldwide. In the United States, the prevalence of obesity is higher in African Americans than whites, even after adjustment for socioeconomic status (SES). This leads to the hypothesis that differences in genetic background may contribute to racial/ethnic differences in obesity-related traits. We tested this hypothesis by conducting a genome-wide admixture mapping scan using 1,350 ancestry-informative single-nucleotide polymorphisms (SNPs) in 3,531 self-identified blacks from the Atherosclerosis Risk in Communities (ARIC) study. We used these markers to estimate the overall proportions of European ancestry (PEAs) for each individual and then scanned for the association between PEA and obesity-related traits (both continuous and dichotomous) at each locus. The median (interquartile range) PEA was 0.151 (0.115). PEA was inversely correlated with continuous BMI, weight, and subscapular skinfold thickness, even after adjusting for socioeconomic factors. In contrast, PEA was positively correlated with BMI-adjusted waist circumference. Using admixture mapping on dichotomized traits, we identified a locus on 2p23.3 to be suggestively associated with BMI (locus-specific lod = 4.11) and weight (locus-specific lod = 4.07). After adjusting for global PEA, each additional copy of a European ancestral allele at the 2p23.3 peak was associated with a BMI decrease of ~0.92 kg/m(2) (P = 2.9 x 10(-5)). Further mapping in this region on chromosome 2 may be able to uncover causative variants underlying obesity, which may offer insights into the control of energy homeostasis.
Link
September 01, 2009
How humans differ from animals in height and mass variation (McKellar & Hendry 2009)
The authors found that humans within populations have more variation in mass than most animals do. In other words, there are many "thin" and "fat" people in human populations. This isn't very surprising to me, because in developing countries, socioeconomic differences may account for these differences (e.g., some people starve), while in developed countries, most people are employed in jobs and perform activities where having an optimal body mass is not that important for your survival and reproduction.
When it comes to height, humans show a very low within-population differentiation. In other words, most humans are around the "average" height, and really short and really tall ones are not that common. My guess is that this has something to do with the extreme socialization of humans; really short and really tall individuals (although the patterns are gender-specific) do have trouble in human society, if we judge from marriage ads where desired height is often specified, or from various pieces of technology (shields, spears, doors, steps, clothes, etc) which are designed for people of a particular height.
When it comes to height, humans show a very low within-population differentiation. In other words, most humans are around the "average" height, and really short and really tall ones are not that common. My guess is that this has something to do with the extreme socialization of humans; really short and really tall individuals (although the patterns are gender-specific) do have trouble in human society, if we judge from marriage ads where desired height is often specified, or from various pieces of technology (shields, spears, doors, steps, clothes, etc) which are designed for people of a particular height.
However, between-population differentiation in height is substantial. While we are in the 8th/4th percentiles in our within-population differentiation (very uniform), we are in the 47th/51st percentiles in our between-population differentiation. Thus, while in absolute terms between-population differences are average, these contrast greatly with our very low within-population differences: Human populations appear to be very different from each other in terms of their height.
From the paper:
PLoS ONE 4(9): e6876. doi:10.1371/journal.pone.0006876
How Humans Differ from Other Animals in Their Levels of Morphological Variation
Ann E. McKellar, Andrew P. Hendry
Abstract
Animal species come in many shapes and sizes, as do the individuals and populations that make up each species. To us, humans might seem to show particularly high levels of morphological variation, but perhaps this perception is simply based on enhanced recognition of individual conspecifics relative to individual heterospecifics. We here more objectively ask how humans compare to other animals in terms of body size variation. We quantitatively compare levels of variation in body length (height) and mass within and among 99 human populations and 848 animal populations (210 species). We find that humans show low levels of within-population body height variation in comparison to body length variation in other animals. Humans do not, however, show distinctive levels of within-population body mass variation, nor of among-population body height or mass variation. These results are consistent with the idea that natural and sexual selection have reduced human height variation within populations, while maintaining it among populations. We therefore hypothesize that humans have evolved on a rugged adaptive landscape with strong selection for body height optima that differ among locations.
Link
One interesting result was that humans, in comparison to other animals, show a high level of within-population variation in mass considering their within-population variation in height (Figure 1). Specifically, when considering residuals from a regression of within-population CVs for mass on within-population CVs for length, human males and females fell into the 71st and 91st percentiles, respectively, for the entire distribution of animal species.
...
Another interesting result was that humans show low within-population variation in body height in comparison to body length in non-human animals (Figure 2), but the same was not true for human mass relative to animal mass (Figure S1). These differences can be quantified through several different comparisons. First, the mean within-population CVs for male and female human height correspond to the 8th and 4th percentiles, respectively, of the mean within-population CVs for animal length. In contrast, the mean within-population CVs for male and female human mass correspond to the 56th and 60th percentiles, respectively, of the within-population CVs for animal mass.
...
Specifically, the mean among-population CVs for male and female human height correspond to the 47th and 51st percentiles, respectively, of mean among-population CVs for animal length. Illustrated another way, humans show relatively low levels of within-population variation in height given their among-population variation in height (Figure 3).
PLoS ONE 4(9): e6876. doi:10.1371/journal.pone.0006876
How Humans Differ from Other Animals in Their Levels of Morphological Variation
Ann E. McKellar, Andrew P. Hendry
Abstract
Animal species come in many shapes and sizes, as do the individuals and populations that make up each species. To us, humans might seem to show particularly high levels of morphological variation, but perhaps this perception is simply based on enhanced recognition of individual conspecifics relative to individual heterospecifics. We here more objectively ask how humans compare to other animals in terms of body size variation. We quantitatively compare levels of variation in body length (height) and mass within and among 99 human populations and 848 animal populations (210 species). We find that humans show low levels of within-population body height variation in comparison to body length variation in other animals. Humans do not, however, show distinctive levels of within-population body mass variation, nor of among-population body height or mass variation. These results are consistent with the idea that natural and sexual selection have reduced human height variation within populations, while maintaining it among populations. We therefore hypothesize that humans have evolved on a rugged adaptive landscape with strong selection for body height optima that differ among locations.
Link
August 31, 2009
Eye-tracking of men's preferences for women's body shape
Arch Sex Behav. 2009 Aug 18. [Epub ahead of print]
Eye-Tracking of Men's Preferences for Waist-to-Hip Ratio and Breast Size of Women.
Dixson BJ, Grimshaw GM, Linklater WL, Dixson AF.
Studies of human physical traits and mate preferences often use questionnaires asking participants to rate the attractiveness of images. Female waist-to-hip ratio (WHR), breast size, and facial appearance have all been implicated in assessments by men of female attractiveness. However, very little is known about how men make fine-grained visual assessments of such images. We used eye-tracking techniques to measure the numbers of visual fixations, dwell times, and initial fixations made by men who viewed front-posed photographs of the same woman, computer-morphed so as to differ in her WHR (0.7 or 0.9) and breast size (small, medium, or large). Men also rated these images for attractiveness. Results showed that the initial visual fixation (occurring within 200 ms from the start of each 5 s test) involved either the breasts or the waist. Both these body areas received more first fixations than the face or the lower body (pubic area and legs). Men looked more often and for longer at the breasts, irrespective of the WHR of the images. However, men rated images with an hourglass shape and a slim waist (0.7 WHR) as most attractive, irrespective of breast size. These results provide quantitative data on eye movements that occur during male judgments of the attractiveness of female images, and indicate that assessments of the female hourglass figure probably occur very rapidly.
Link
Eye-Tracking of Men's Preferences for Waist-to-Hip Ratio and Breast Size of Women.
Dixson BJ, Grimshaw GM, Linklater WL, Dixson AF.
Studies of human physical traits and mate preferences often use questionnaires asking participants to rate the attractiveness of images. Female waist-to-hip ratio (WHR), breast size, and facial appearance have all been implicated in assessments by men of female attractiveness. However, very little is known about how men make fine-grained visual assessments of such images. We used eye-tracking techniques to measure the numbers of visual fixations, dwell times, and initial fixations made by men who viewed front-posed photographs of the same woman, computer-morphed so as to differ in her WHR (0.7 or 0.9) and breast size (small, medium, or large). Men also rated these images for attractiveness. Results showed that the initial visual fixation (occurring within 200 ms from the start of each 5 s test) involved either the breasts or the waist. Both these body areas received more first fixations than the face or the lower body (pubic area and legs). Men looked more often and for longer at the breasts, irrespective of the WHR of the images. However, men rated images with an hourglass shape and a slim waist (0.7 WHR) as most attractive, irrespective of breast size. These results provide quantitative data on eye movements that occur during male judgments of the attractiveness of female images, and indicate that assessments of the female hourglass figure probably occur very rapidly.
Link
August 03, 2009
Strong men and tender women in Bronze Age Serbia
Journal of Anthropological Archaeology doi:10.1016/j.jaa.2009.06.001
Physical activity and social status in Early Bronze Age society: The Mokrin necropolis
Marko Porčić and Sofija Stefanović
Abstract
This paper investigates the social structure of an Early Bronze Age society whose members were buried at the necropolis of Mokrin (Serbia, Southeastern Europe), by comparative analysis of musculo-skeletal markers (MSM) of activity and social status as induced on the basis of grave contents. The main objective of the analysis is to determine whether quantitative and qualitative differences in activity are related to social status. Besides using an overall measure of activity, we attempted to isolate different qualitative aspects (facets) of activity through factor analysis of MSM scores. No correlation between social status and overall labor intensity was found. However, there are clues that social status and a single facet of activity are related. Positive correlation between vertical status and the intensity of use of upper arm and shoulder muscles was found among male individuals, while negative correlation between the aforementioned variables was found among the females. The general conclusion based on the results of this study is that there is no simple correlation between the overall labor intensity and social status.
Link
Physical activity and social status in Early Bronze Age society: The Mokrin necropolis
Marko Porčić and Sofija Stefanović
Abstract
This paper investigates the social structure of an Early Bronze Age society whose members were buried at the necropolis of Mokrin (Serbia, Southeastern Europe), by comparative analysis of musculo-skeletal markers (MSM) of activity and social status as induced on the basis of grave contents. The main objective of the analysis is to determine whether quantitative and qualitative differences in activity are related to social status. Besides using an overall measure of activity, we attempted to isolate different qualitative aspects (facets) of activity through factor analysis of MSM scores. No correlation between social status and overall labor intensity was found. However, there are clues that social status and a single facet of activity are related. Positive correlation between vertical status and the intensity of use of upper arm and shoulder muscles was found among male individuals, while negative correlation between the aforementioned variables was found among the females. The general conclusion based on the results of this study is that there is no simple correlation between the overall labor intensity and social status.
Link
May 24, 2009
European admixture and Body Mass Index in African Americans
While a larger portion of African ancestry in African Americans is associated with higher probability of obesity, a larger portion of African ancestry in a particular locus actually reduced the probability of obesity. This underscores the importance of not relying on first-order approximations (racial identity) when more detailed information is available.
From the paper:
Admixture Mapping of 15,280 African Americans Identifies Obesity Susceptibility Loci on Chromosomes 5 and X
Ching-Yu Cheng et al.
Abstract
The prevalence of obesity (body mass index (BMI) ≥30 kg/m2) is higher in African Americans than in European Americans, even after adjustment for socioeconomic factors, suggesting that genetic factors may explain some of the difference. To identify genetic loci influencing BMI, we carried out a pooled analysis of genome-wide admixture mapping scans in 15,280 African Americans from 14 epidemiologic studies. Samples were genotyped at a median of 1,411 ancestry-informative markers. After adjusting for age, sex, and study, BMI was analyzed both as a dichotomized (top 20% versus bottom 20%) and a continuous trait. We found that a higher percentage of European ancestry was significantly correlated with lower BMI (ρ = −0.042, P = 1.6×10−7). In the dichotomized analysis, we detected two loci on chromosome X as associated with increased African ancestry: the first at Xq25 (locus-specific LOD = 5.94; genome-wide score = 3.22; case-control Z = −3.94); and the second at Xq13.1 (locus-specific LOD = 2.22; case-control Z = −4.62). Quantitative analysis identified a third locus at 5q13.3 where higher BMI was highly significantly associated with greater European ancestry (locus-specific LOD = 6.27; genome-wide score = 3.46). Further mapping studies with dense sets of markers will be necessary to identify the alleles in these regions of chromosomes X and 5 that may be associated with variation in BMI.
Link
From the paper:
We have carried out admixture mapping analyses to search for genomic regions associated with BMI. This pooled analysis of samples from 14 studies is the largest admixture scan reported to date. In more than 15,000 individuals, we identified a locus on chromosome 5 where greater local European ancestry was associated with higher levels of BMI (P = 5.8×10−7), and two regions on chromosome X where greater local European ancestry was associated with lower levels of BMI (both P<5.0×10−6). Each of these three associations was above and beyond the contribution of genome-wide European ancestry, and each reached genome-wide significance.PLoS Genetics doi:10.1371/journal.pgen.1000490
...
The inverse correlation between BMI and percentage of European ancestry estimated on the genome-wide scale confirmed the results from previous studies of smaller sample size and fewer markers [29],[30]. However, while genome-wide ancestry is likely correlated with local ancestry, it cannot fully capture ancestry information at each locus as there exists variation across the genome in the effects of locus-specific ancestry on obesity. In particular, local European ancestry at 5q13.3 was positively associated with BMI, providing the first evidence of a genome-wide significant ancestry association being in the opposite direction to the overall epidemiological association.
Admixture Mapping of 15,280 African Americans Identifies Obesity Susceptibility Loci on Chromosomes 5 and X
Ching-Yu Cheng et al.
Abstract
The prevalence of obesity (body mass index (BMI) ≥30 kg/m2) is higher in African Americans than in European Americans, even after adjustment for socioeconomic factors, suggesting that genetic factors may explain some of the difference. To identify genetic loci influencing BMI, we carried out a pooled analysis of genome-wide admixture mapping scans in 15,280 African Americans from 14 epidemiologic studies. Samples were genotyped at a median of 1,411 ancestry-informative markers. After adjusting for age, sex, and study, BMI was analyzed both as a dichotomized (top 20% versus bottom 20%) and a continuous trait. We found that a higher percentage of European ancestry was significantly correlated with lower BMI (ρ = −0.042, P = 1.6×10−7). In the dichotomized analysis, we detected two loci on chromosome X as associated with increased African ancestry: the first at Xq25 (locus-specific LOD = 5.94; genome-wide score = 3.22; case-control Z = −3.94); and the second at Xq13.1 (locus-specific LOD = 2.22; case-control Z = −4.62). Quantitative analysis identified a third locus at 5q13.3 where higher BMI was highly significantly associated with greater European ancestry (locus-specific LOD = 6.27; genome-wide score = 3.46). Further mapping studies with dense sets of markers will be necessary to identify the alleles in these regions of chromosomes X and 5 that may be associated with variation in BMI.
Link
April 26, 2009
Body mass index and depression
BMC Public Health 2009, 9:14doi:10.1186/1471-2458-9-14
Depression and body mass index, a u-shaped association
Leonore M de Wit et al.
Abstract
Background
Results of studies concerning the association between obesity and depression are conflicting. Some find a positive association, some a negative association and some find no association at all. Most studies, however, examine a linear association between Body Mass Index (BMI) and depression. The present study investigates if a nonlinear (U-shaped) trend is preferable over a linear trend to describe the relationship between BMI and depression, which means that both underweight and obesity are associated with depression.
Methods
We investigated the existence of such a U-curve in a sample of 43,534 individuals, aged between 18–90 years, who participated in a cross-sectional study (Continuous Survey of Living Conditions) of physical and mental health in the general population of the Netherlands. We calculated linear and nonlinear (quadratic) ANOVA with polynomial contrast and curve fit regression statistics to investigate whether there was a U-shaped trend in the association between BMI and depression.
Results
We find a very significant U-shaped association between BMI categories (underweight, normal, overweight and obesity) and depression (p ≤ 0.001). There is a trend indicating a significant difference in the association between males and females (p = 0.05). We find a very significant U-shaped (quadratic) association between BMI (BMI2) and depression (p ≤ 0.001), continuous BMI is not linearly associated with depression (p = 0.514).
Conclusion
The results of this study give evidence for a significant U-shaped trend in the association between BMI and depression.
Link
Depression and body mass index, a u-shaped association
Leonore M de Wit et al.
Abstract
Background
Results of studies concerning the association between obesity and depression are conflicting. Some find a positive association, some a negative association and some find no association at all. Most studies, however, examine a linear association between Body Mass Index (BMI) and depression. The present study investigates if a nonlinear (U-shaped) trend is preferable over a linear trend to describe the relationship between BMI and depression, which means that both underweight and obesity are associated with depression.
Methods
We investigated the existence of such a U-curve in a sample of 43,534 individuals, aged between 18–90 years, who participated in a cross-sectional study (Continuous Survey of Living Conditions) of physical and mental health in the general population of the Netherlands. We calculated linear and nonlinear (quadratic) ANOVA with polynomial contrast and curve fit regression statistics to investigate whether there was a U-shaped trend in the association between BMI and depression.
Results
We find a very significant U-shaped association between BMI categories (underweight, normal, overweight and obesity) and depression (p ≤ 0.001). There is a trend indicating a significant difference in the association between males and females (p = 0.05). We find a very significant U-shaped (quadratic) association between BMI (BMI2) and depression (p ≤ 0.001), continuous BMI is not linearly associated with depression (p = 0.514).
Conclusion
The results of this study give evidence for a significant U-shaped trend in the association between BMI and depression.
Link
March 12, 2009
Body proportions in Neolithic Germany
Homo doi:10.1016/j.jchb.2008.05.006
Population continuity, demic diffusion and Neolithic origins in central-southern Germany: The evidence from body proportions.
Gallagher A, Gunther MM, Bruchhaus H.
Abstract
The transition to agro-pastoralism in central Europe has been framed within a dichotomy of "regional continuity" versus exogenous "demic diffusion". While substantial genetic support exists for a model of demographic diffusion from an ancestral source in the Near East, archaeological data furnish weak support for the "wave of advance" model. Nevertheless, archaeological evidence attests the widespread introduction of an exogenous "package" comprising ceramics, cereals, pulses and domesticated animals to central Europe at 5600calBCE. Body proportions are under strong climatic selection and evince remarkable stability within regional lineages. As such, they offer a viable and robust alternative to cranio-facial data in assessing hypothesised continuity and replacement with the transition to agro-pastoralism in central Europe. Humero-clavicular, brachial and crural indices in a large sample (n=75) of Linienbandkeramik (LBK), Late Neolithic and Early Bronze Age specimens from the middle Elbe-Saale-Werra valley (MESV) were compared with Eurasian and African terminal Pleistocene, European Mesolithic and geographically disparate recent human specimens. Mesolithic Europeans display considerable variation in humero-clavicular and brachial indices yet none approach the extreme "hyper-polar" morphology of LBK humans from the MESV. In contrast, Late Neolithic and Early Bronze Age peoples display elongated brachial and crural indices reminiscent of terminal Pleistocene and "tropically adapted" recent humans. These marked morphological changes likely reflect exogenous immigration during the terminal Fourth millennium cal BC. Population expansion and diffusion is a function of increased mobility and settlement dispersal concomitant with significant technological and subsistence changes in later Neolithic societies during the late fourth millennium cal BCE.
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Population continuity, demic diffusion and Neolithic origins in central-southern Germany: The evidence from body proportions.
Gallagher A, Gunther MM, Bruchhaus H.
Abstract
The transition to agro-pastoralism in central Europe has been framed within a dichotomy of "regional continuity" versus exogenous "demic diffusion". While substantial genetic support exists for a model of demographic diffusion from an ancestral source in the Near East, archaeological data furnish weak support for the "wave of advance" model. Nevertheless, archaeological evidence attests the widespread introduction of an exogenous "package" comprising ceramics, cereals, pulses and domesticated animals to central Europe at 5600calBCE. Body proportions are under strong climatic selection and evince remarkable stability within regional lineages. As such, they offer a viable and robust alternative to cranio-facial data in assessing hypothesised continuity and replacement with the transition to agro-pastoralism in central Europe. Humero-clavicular, brachial and crural indices in a large sample (n=75) of Linienbandkeramik (LBK), Late Neolithic and Early Bronze Age specimens from the middle Elbe-Saale-Werra valley (MESV) were compared with Eurasian and African terminal Pleistocene, European Mesolithic and geographically disparate recent human specimens. Mesolithic Europeans display considerable variation in humero-clavicular and brachial indices yet none approach the extreme "hyper-polar" morphology of LBK humans from the MESV. In contrast, Late Neolithic and Early Bronze Age peoples display elongated brachial and crural indices reminiscent of terminal Pleistocene and "tropically adapted" recent humans. These marked morphological changes likely reflect exogenous immigration during the terminal Fourth millennium cal BC. Population expansion and diffusion is a function of increased mobility and settlement dispersal concomitant with significant technological and subsistence changes in later Neolithic societies during the late fourth millennium cal BCE.
Link
January 04, 2009
Waist-to-Hip Ratio across cultures
CURRENT ANTHROPOLOGY Volume 49, Number 6, December 2008
DOI: 10.1086/593036
Waist-to-Hip Ratio across Cultures: Trade-Offs between Androgen- and Estrogen-Dependent Traits
Elizabeth Cashdan
Abstract
A gynoid pattern of fat distribution, with small waist and large hips (low waist-to-hip ratio, or WHR) holds significant fitness benefits for women: women with a low WHR of about 0.7 are more fecund, are less prone to chronic disease, and (in most cultures) are considered more attractive. Why, then, do nearly all women have a WHR higher than this putative optimum? Is the marked variation in this trait adaptive? This paper first documents the conundrum by showing that female WHR, especially in non-Western populations, is higher than the putative optimum even among samples that are young, lean, and dependent on traditional diets. The paper then proposes compensating benefits to a high WHR that can explain both its prevalence and variation in the trait. The evidence indicates that the hormonal profile associated with high WHR (high androgen and cortisol levels, low estrogens) favors success in resource competition, particularly under stressful and difficult circumstances, even though this carries fitness costs in fecundity and health. Adrenal androgens, in particular, may play an important role in enabling women to respond to stressful challenges.
Link
DOI: 10.1086/593036
Waist-to-Hip Ratio across Cultures: Trade-Offs between Androgen- and Estrogen-Dependent Traits
Elizabeth Cashdan
Abstract
A gynoid pattern of fat distribution, with small waist and large hips (low waist-to-hip ratio, or WHR) holds significant fitness benefits for women: women with a low WHR of about 0.7 are more fecund, are less prone to chronic disease, and (in most cultures) are considered more attractive. Why, then, do nearly all women have a WHR higher than this putative optimum? Is the marked variation in this trait adaptive? This paper first documents the conundrum by showing that female WHR, especially in non-Western populations, is higher than the putative optimum even among samples that are young, lean, and dependent on traditional diets. The paper then proposes compensating benefits to a high WHR that can explain both its prevalence and variation in the trait. The evidence indicates that the hormonal profile associated with high WHR (high androgen and cortisol levels, low estrogens) favors success in resource competition, particularly under stressful and difficult circumstances, even though this carries fitness costs in fecundity and health. Adrenal androgens, in particular, may play an important role in enabling women to respond to stressful challenges.
Link
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