The relationship between mental well-being and wealth varies by wealth type, place and sex/gender: Evidence from Namibia.

This paper explores the impact of livelihood strategies and place on mental well-being. Identifying different socioeconomic factors that impact mental well-being across contexts is pressing given the global rise in mental health disorders. Numerous studies in the population and social sciences have emphasized the protective role of material wealth on human health and well-being; however, scholars frequently assess wealth as a one-dimensional variable, which may fail to capture diverse forms of wealth. Acknowledging different forms of wealth may be particularly important in settings where agricultural economies coexist with cash economies. Using data from the 2013 Namibia Demographic Health Survey (n = 13 377), we use a newly developed measure of success in agricultural activities, an agricultural wealth index, or AWI, generated by Hackman et al., (2021). To examine the role of different forms of wealth on mental health symptoms. We find mental well-being, assessed through three survey questions, is lower among urban dwellers and females and shows varied associations with wealth type and sex/gender. In general, success in agricultural activities is associated with better mental well-being, while the association with market success is null or and conditional upon sex/gender and place. This study adds to recent work on the value of using multidimensional measures of wealth and raises important questions about why wealth type and sex/gender differentially impact mental well-being.

The relationship between altitude and BMI varies across low- and middle-income countries.

OBJECTIVES: Studies suggest that living at high altitude decreases obesity risk, but this research is limited to single-country analyses. We examine the relationship between altitude and body mass index (BMI) among women living in a diverse sample of low- and middle-income countries. MATERIALS AND METHODS: Using Demographic and Health Survey data from 1 583 456 reproductive age women (20-49 years) in 54 countries, we fit regression models predicting BMI and obesity by altitude controlling for a range of demographic factors-age, parity, breastfeeding status, wealth, and education. RESULTS: A mixed-effects model with country-level random intercepts and slopes predicts an overall -0.162 kg/m2 (95% CI -0.220, -0.104) reduction in BMI and lower odds of obesity (OR 0.90, 95% CI 0.87, 0.95) for every 200 m increase in altitude. However, countries vary dramatically in whether they exhibit a negative or positive association between altitude and BMI (34 countries negative, 20 positive). Mixed findings also arise when examining odds of obesity. DISCUSSION: We show that past findings of declining obesity risk with altitude are not universal. Increasing altitude predicts slightly lower BMIs at the global level, but the relationship within individual countries varies in both strength and direction.

Subjective social status and mental health among adolescents in Ethiopia: Evidence from a panel study.

Numerous studies have found that a relationship between subjective status and measures of human health persists even after controlling for objective measures, including income, education, and assets. However, few studies have probed how status shapes health among adolescents, particularly those in low-and-middle-income settings. This study examines the relative effects of subjective and objective status on mental health among Ethiopian adolescents. Using data from two waves of the Jimma Longitudinal Family Survey of Youth (N = 1,045), this study uses a combination of linear regression and linear mixed-effects models to examine the relationships between objective social status, subjective social status, and mental well-being among adolescents in Ethiopia. Three measures of objective status, including household income, adolescent education, and a multidimensional measure of material wealth, were assessed. Social network and support variables were constructed using factor analysis. A community version of the 10-rung McArthur ladder was used to assess the subjective socioeconomic status of adolescents. The self-reporting questionnaire was used to assess mental well-being during both waves of the study. The significant effect of higher subjective status on reports of fewer non-specific psychological distress (-0.28; 95% CI: -0.43 to -0.14) was not mediated by objective status, material deprivation, or social support covariates. The observed relationship between status and mental well-being was consistent across successive study waves. Among a cohort of adolescents in Jimma, Ethiopia, several measures of objective status are associated with subjective status. However, akin to research among adults, the findings of our study suggest that the relationship between adolescent subjective social status and mental health persists above and beyond the effects of objective status. Future research is needed on the factors, environments, and experiences that inform adolescent perceptions of status and well-being over time.

Unpacking the "black box" of global food insecurity and mental health.

Food insecurity is a global concern. While it was once characterized mainly as a problem of undernutrition, it is now recognized that a person may be food insecure without experiencing hunger. Numerous studies have demonstrated that food insecurity is strongly related to poor mental health around the world, but the mechanisms that underpin that relationship remain poorly understood. One body of research from nutritional sciences posits that nutrient deficiency impacts brain function, producing symptoms of depression and anxiety. Another body of research from the social sciences posits that the social consequences of having to eat non-preferred foods or obtain food in socially unacceptable ways may compromise mental health through stress. This study was designed to clarify the mechanisms linking food insecurity and mental health using case studies in rural Brazil and urban Ethiopia. Working with samples consisting of about 200 adult household decision-makers (mostly female) recruited between 2015 and 2019 at each site, we tested for nutritional and social mediation of the food insecurity-mental health relationship using multivariable linear regression and mediation analysis. Our analyses found no evidence of mediation in either setting. Moreover, there was no association between nutritional status variables and food insecurity. These findings suggest that food insecurity likely impacts mental health directly through forms of basic needs deprivation, such as worrying about where one's next meal will come from, rather than by acting as a social signal or even by impacting nutritional status. These results underscore the power of basic-needs deprivation for impacting mental health.

Do People Agree on What Foods are Prestigious? Evidence of a Single, Shared Cultural Model of Food in Urban Ethiopia and Rural Brazil.

To what extent do people agree on the meaning of foods, and does this vary by socioeconomic status, demographics, or household type? Addressing this question is critical for testing hypotheses about the relationship between food insecurity, food meaning, and mental well-being because it speaks directly to the social implications of food behaviors. In this study, we test for a shared cultural model of food meaning in two diverse settings: urban Ethiopia and rural Brazil. Using freelist and pile sort data from 63 respondents in Ethiopia and 62 from Brazil, we show strong consensus on the prestige value of various key food items in each context. Further, consensus varies little across household composition, food security status, and age and gender. This suggests that, in these two settings, consumption of widely available foods is an act that has both biological and social consequences.

Understanding and defining sanitation insecurity: women's gendered experiences of urination, defecation and menstruation in rural Odisha, India.

BACKGROUND: Research suggests that the lived experience of inadequate sanitation may contribute to poor health outcomes above and beyond pathogen exposure, particularly among women. The goal of this research was to understand women's lived experiences of sanitation by documenting their urination-related, defecation-related and menstruation-related concerns, to use findings to develop a definition of sanitation insecurity among women in low-income settings and to develop a conceptual model to explain the factors that contribute to their experiences, including potential behavioural and health consequences. METHODS: We conducted 69 Free-List Interviews and eight focus group discussions in a rural population in Odisha, India to identify women's sanitation concerns and to build an understanding of sanitation insecurity. FINDINGS: We found that women at different life stages in rural Odisha, India have a multitude of unaddressed urination, defecation and menstruation concerns. Concerns fell into four domains: the sociocultural context, the physical environment, the social environment and personal constraints. These varied by season, time of day, life stage and toilet ownership, and were linked with an array of adaptations (ie, suppression, withholding food and water) and consequences (ie, scolding, shame, fear). Our derived definition and conceptual model of sanitation insecurity reflect these four domains. DISCUSSION: To sincerely address women's sanitation needs, our findings indicate that more is needed than facilities that change the physical environment alone. Efforts to enable urinating, defecating and managing menstruation independently, comfortably, safely, hygienically, privately, healthily, with dignity and as needed require transformative approaches that also address the gendered, sociocultural and social environments that impact women despite facility access. This research lays the groundwork for future sanitation studies to validate or refine the proposed definition and to assess women's sanitation insecurity, even among those who have latrines, to determine what may be needed to improve women's sanitation circumstances.

Stability and Change in In-Group Mate Preferences among Young People in Ethiopia Are Predicted by Food Security and Gender Attitudes, but Not by Expected Pathogen Exposures.

There is broad anthropological interest in understanding how people define "insiders" and "outsiders" and how this shapes their attitudes and behaviors toward others. As such, a suite of hypotheses has been proposed to account for the varying degrees of in-group preference between individuals and societies. We test three hypotheses related to material insecurity, pathogen stress, and views of gender equality among cross-sectional (n = 1896) and longitudinal (n = 1002) samples of young people in Ethiopia (aged 13-17 years at baseline) to explore stability and change in their preferences for coethnic spouses. We show that food insecurity is associated with a greater likelihood of intolerant mate preferences. We also find that young people who hold more gender equitable attitudes tended to hold more tolerant mate preferences. Finally, we find no support for the hypothesis that expected pathogen exposure is associated with intolerant mate preferences. Our results most strongly support a material insecurity hypothesis of in-group bias, which assumes that uncertainty over meeting basic needs leads people to favor those in their in-group. As such, our findings join a small but growing group of studies that highlight the importance of material insecurity for understanding tolerance, xenophobia, in-group bias, and favoritism.

Material wealth in 3D: Mapping multiple paths to prosperity in low- and middle- income countries.

Material wealth is a key factor shaping human development and well-being. Every year, hundreds of studies in social science and policy fields assess material wealth in low- and middle-income countries assuming that there is a single dimension by which households can move from poverty to prosperity. However, a one-dimensional model may miss important kinds of prosperity, particularly in countries where traditional subsistence-based livelihoods coexist with modern cash economies. Using multiple correspondence analysis to analyze representative household data from six countries-Nepal, Bangladesh, Ethiopia, Kenya, Tanzania and Guatemala-across three world regions, we identify a number of independent dimension of wealth, each with a clear link to locally relevant pathways to success in cash and agricultural economies. In all cases, the first dimension identified by this approach replicates standard one-dimensional estimates and captures success in cash economies. The novel dimensions we identify reflect success in different agricultural sectors and are independently associated with key benchmarks of food security and human growth, such as adult body mass index and child height. The multidimensional models of wealth we describe here provide new opportunities for examining the causes and consequences of wealth inequality that go beyond success in cash economies, for tracing the emergence of hybrid pathways to prosperity, and for assessing how these different pathways to economic success carry different health risks and social opportunities.

Testing ecological and universal models of body shape and child health using a global sample of infants and young children.

AIM: To test whether a risk of child illness is best predicted by deviations from a population-specific growth distribution or a universal growth distribution. SUBJECTS AND METHODS: Child weight for height and child illness data from 433 776 children (1-59 months) from 47 different low and lower income countries are used in regression models to estimate for each country the child basal weight for height. This study assesses the extent to which individuals within populations deviate from their basal slenderness. It uses correlation and regression techniques to estimate the relationship between child illness (diarrhoea, fever or cough) and basal weight for height, and residual weight for height. RESULTS: In bivariate tests, basal weight for height z-score did not predict the country level prevalence of child illness (r2 = -0.01, n = 47, p = 0.53), but excess weight for height did (r2 = 0.14, p < 0.01). At the individual level, household wealth is negatively associated with the odds that a child is reported as ill (beta = -0.04, p < 0.001, n = 433 776) and basal weight for height was not (beta = 0.20, p = 0.27). Deviations from country-specific basal weight for height were negatively associated with the likelihood of illness (beta = -0.13, p < 0.01), indicating a 13% reduction in illness risk for every 0.1 standard deviation increase in residual weight-for-height Conclusion: These results are consistent with the idea that populations may differ in their body slenderness, and that deviations from this body form may predict the risk of childhood illness.

Agency as a mediator in the pathway from transactional sex to HIV among pregnant women in Swaziland: a multigroup path analysis.

INTRODUCTION: Transactional sex is a structural driver of HIV for women and girls in sub-Saharan Africa. In transactional relationships, sexual and economic obligations intertwine and may have positive and negative effects on women's financial standing and social status. We conducted a clinic-based survey with pregnant women in Swaziland using a locally validated transactional sex scale to measure the association between subjective social status, transactional sex, and HIV status, and to assess whether this association differed according to a woman's agency within her relationship. METHODS: We recruited a convenience sample of 406 pregnant women at one rural and one urban public antenatal clinic in Swaziland and administered a behavioural survey that was linked to participant HIV status using clinic records. We then conducted a multigroup path analysis to test three hypotheses: (1) that more engagement in transactional sex is associated with decreased condom use and increased subjective social status; (2) that subjective social status mediates the relationship between transactional sex and HIV status; and (3) that these relationships are different across groups according to whether or not a woman reported any indicator of constrained agency within her relationship. RESULTS: The amount and value of material goods received from a sexual partner was significantly and positively associated with higher subjective social status among all participants. As the amount of material goods received from a partner increased, women who reported no indicators of constrained agency were less likely to use condoms. Conversely, there was no relationship between transactional sex and condom use among women who reported any indicator of constrained relationship agency. Among women who reported any indicator of constrained agency, HIV was significantly associated with lower subjective social status. CONCLUSIONS: Relationship agency likely plays a key role in determining which mechanisms create HIV risk for women in transactional relationships. Interventions to mitigate these risks must address social forces that penalize women who engage in sexual relationships as well as structural drivers of gendered economic disparity that reduce women's agency within their sexual and romantic relationships.

Assessing Women's Negative Sanitation Experiences and Concerns: The Development of a Novel Sanitation Insecurity Measure.

Lack of access to acceptable sanitation facilities can expose individuals, particularly women, to physical, social, and mental health risks. While some of the challenges have been documented, standard metrics are needed to determine the extent to which women have urination- and defecation-related concerns and negative experiences. Such metrics also are needed to assess the effectiveness of interventions to mitigate them. We developed a sanitation insecurity measure to capture the range and frequency of women's sanitation-related concerns and negative experiences. Research was conducted in rural Odisha, India with women across various life course stages to reflect a range of perspectives. This paper documents the mixed data collection methods and the exploratory and confirmatory factor analyses we employed to arrive at a final measure. The final sanitation insecurity measure includes 50 items across seven factors that reflect the physical environment, the social environment, and individual-level constraints. Most factor scores were significantly higher for unmarried women and for women who lacked access to functional latrines, indicating social and environmental influence on experiences. This measure will enable researchers to evaluate how sanitation insecurity affects health and to determine if and how sanitation interventions ameliorate women's concerns and negative experiences associated with sanitation.

Measuring material wealth in low-income settings: A conceptual and how-to guide.

Although wealth is consistently found to be an important predictor of health and well-being, there remains debate as to the best way to conceptualize and operationalize wealth. In this article, we focus on the measurement of economic resources, which is one among many forms of wealth. We provide an overview of the process of measuring material wealth, including theoretical and conceptual considerations, a how-to guide based on the most common approach to measurement, and a review of important theoretical and empirical questions that remain to be resolved. Throughout, we emphasize considerations particular to the settings in which anthropologists work, and we include variations on common approaches to measuring material wealth that might be better suited to anthropologists' theoretical questions, methodological approaches, and fieldwork settings.

Food Insecurity and Common Mental Disorders among Ethiopian Youth: Structural Equation Modeling.

BACKGROUND: Although the consequences of food insecurity on physical health and nutritional status of youth living have been reported, its effect on their mental health remains less investigated in developing countries. The aim of this study was to examine the pathways through which food insecurity is associated with poor mental health status among youth living in Ethiopia. METHODS: We used data from Jimma Longitudinal Family Survey of Youth (JLFSY) collected in 2009/10. A total of 1,521 youth were included in the analysis. We measured food insecurity using a 5-items scale and common mental disorders using the 20-item Self-Reporting Questionnaire (SRQ-20). Structural and generalized equation modeling using maximum likelihood estimation method was used to analyze the data. RESULTS: The prevalence of common mental disorders was 30.8% (95% CI: 28.6, 33.2). Food insecurity was independently associated with common mental disorders (ß = 0.323, P<0.05). Most (91.8%) of the effect of food insecurity on common mental disorders was direct and only 8.2% of their relationship was partially mediated by physical health. In addition, poor self-rated health (ß = 0.285, P<0.05), high socioeconomic status (ß = -0.076, P<0.05), parental education (ß = 0.183, P<0.05), living in urban area (ß = 0.139, P<0.05), and female-headed household (ß = 0.192, P<0.05) were associated with common mental disorders. CONCLUSIONS: Food insecurity is directly associated with common mental disorders among youth in Ethiopia. Interventions that aim to improve mental health status of youth should consider strategies to improve access to sufficient, safe and nutritious food.

The feminine ideal and transactional sex: Navigating respectability and risk in Swaziland.

Women who engage in transactional sex are not only at increased risk of HIV and intimate partner violence, but also face social risks including gossip and ostracism. These social and physical risks may be dependent on both what a woman expects and needs from her partner and how her community perceives the relationship. Gender theory suggests that some of these social risks may hinge on whether or not a woman's relationship threatens dominant masculinity. We conducted a qualitative study in Swaziland from September 2013 to October 2014 to explore transactional sex and respectable femininity through the lens of hegemonic gender theory. Using cultural consensus modeling, we identified cultural models of transactional sex and conducted 16 in-depth interviews with model key informants and 3 focus group discussions, for a total of 41 participants. We identified 4 main models of transactional relationships: One typified by marriage and high social respectability, a second in which women aspire towards marriage, a third particular to University students, and a fourth "sugar daddy" model. Women in all models expected and received significant financial support from their male partners. However, women in less respectable relationships risked social censure and stigma if they were discovered, in part because aspects of their relationship threatened hegemonic masculinity. Conversely, women who received male support in respectable relationships had to carefully select HIV risk reduction strategies that did not threaten their relationship and associated social status. Research and programming efforts typically focus only on the less socially respectable forms of transactional sex. This risks reinforcing stigma for women in relationships that are already considered socially unacceptable while ignoring the unique HIV risks faced by women in more respectable relationships.

'Struggling to be the alpha': sources of tension and intimate partner violence in same-sex relationships between men.

In countries such as the USA, gay and bisexual men experience high rates of intimate partner violence. However, little is known about the factors that contribute to this form of violence. In this study, we examine gay and bisexual men's perceptions of sources of tension in same-sex male relationships and how these may contribute to intimate partner violence. We conducted seven focus-group discussions with 64 gay and bisexual men in Atlanta, GA. Focus groups examined men's reactions to the short-form revised Conflicts Tactics Scale to determine if each item was considered to be intimate partner violence if it were to occur among gay and bisexual men. Analysts completed a thematic analysis, using elements of grounded theory. The sources of tension that men identified included: gender role conflict, dyadic inequalities (e.g. differences in income, age, education), differences in 'outness' about sexual identity, substance use, jealousy and external homophobic violence. Results suggest that intimate partner violence interventions for gay and bisexual men should address behavioural factors, while also focusing on structural interventions. Interventions that aim to reduce homophobic stigma and redefine male gender roles may help to address some of the tension that contributes to intimate partner violence in same-sex male relationships.

Cultural consensus modeling to measure transactional sex in Swaziland: Scale building and validation.

Transactional sex is associated with increased risk of HIV and gender based violence in southern Africa and around the world. However the typical quantitative operationalization, "the exchange of gifts or money for sex," can be at odds with a wide array of relationship types and motivations described in qualitative explorations. To build on the strengths of both qualitative and quantitative research streams, we used cultural consensus models to identify distinct models of transactional sex in Swaziland. The process allowed us to build and validate emic scales of transactional sex, while identifying key informants for qualitative interviews within each model to contextualize women's experiences and risk perceptions. We used logistic and multinomial logistic regression models to measure associations with condom use and social status outcomes. Fieldwork was conducted between November 2013 and December 2014 in the Hhohho and Manzini regions. We identified three distinct models of transactional sex in Swaziland based on 124 Swazi women's emic valuation of what they hoped to receive in exchange for sex with their partners. In a clinic-based survey (n = 406), consensus model scales were more sensitive to condom use than the etic definition. Model consonance had distinct effects on social status for the three different models. Transactional sex is better measured as an emic spectrum of expectations within a relationship, rather than an etic binary relationship type. Cultural consensus models allowed us to blend qualitative and quantitative approaches to create an emicly valid quantitative scale grounded in qualitative context.

A comparison of plasma and prostate lycopene in response to typical servings of tomato soup, sauce or juice in men before prostatectomy.

Tomato product consumption and estimated lycopene intake are hypothesised to reduce the risk of prostate cancer. To define the impact of typical servings of commercially available tomato products on resultant plasma and prostate lycopene concentrations, men scheduled to undergo prostatectomy (n 33) were randomised either to a lycopene-restricted control group ( < 5 mg lycopene/d) or to a tomato soup (2-2¾ cups prepared/d), tomato sauce (142-198 g/d or 5-7 ounces/d) or vegetable juice (325-488 ml/d or 11-16·5 fluid ounces/d) intervention providing 25-35 mg lycopene/d. Plasma and prostate carotenoid concentrations were measured by HPLC. Tomato soup, sauce and juice consumption significantly increased plasma lycopene concentration from 0·68 (sem 0·1) to 1·13 (sem 0·09) µmol/l (66 %), 0·48 (sem 0·09) to 0·82 (sem 0·12) µmol/l (71 %) and 0·49 (sem 0·12) to 0·78 (sem 0·1) µmol/l (59 %), respectively, while the controls consuming the lycopene-restricted diet showed a decline in plasma lycopene concentration from 0·55 (sem 0·60) to 0·42 (sem 0·07) µmol/l ( - 24 %). The end-of-study prostate lycopene concentration was 0·16 (sem 0·02) nmol/g in the controls, but was 3·5-, 3·6- and 2·2-fold higher in tomato soup (P= 0·001), sauce (P= 0·001) and juice (P= 0·165) consumers, respectively. Prostate lycopene concentration was moderately correlated with post-intervention plasma lycopene concentrations (r 0·60, P =0·001), indicating that additional factors have an impact on tissue concentrations. While the primary geometric lycopene isomer in tomato products was all-trans (80-90 %), plasma and prostate isomers were 47 and 80 % cis, respectively, demonstrating a shift towards cis accumulation. Consumption of typical servings of processed tomato products results in differing plasma and prostate lycopene concentrations. Factors including meal composition and genetics deserve further evaluation to determine their impacts on lycopene absorption and biodistribution.

Estimating the absolute wealth of households.

OBJECTIVE: To estimate the absolute wealth of households using data from demographic and health surveys. METHODS: We developed a new metric, the absolute wealth estimate, based on the rank of each surveyed household according to its material assets and the assumed shape of the distribution of wealth among surveyed households. Using data from 156 demographic and health surveys in 66 countries, we calculated absolute wealth estimates for households. We validated the method by comparing the proportion of households defined as poor using our estimates with published World Bank poverty headcounts. We also compared the accuracy of absolute versus relative wealth estimates for the prediction of anthropometric measures. FINDINGS: The median absolute wealth estimates of 1,403,186 households were 2056 international dollars per capita (interquartile range: 723-6103). The proportion of poor households based on absolute wealth estimates were strongly correlated with World Bank estimates of populations living on less than 2.00 United States dollars per capita per day (R(2) = 0.84). Absolute wealth estimates were better predictors of anthropometric measures than relative wealth indexes. CONCLUSION: Absolute wealth estimates provide new opportunities for comparative research to assess the effects of economic resources on health and human capital, as well as the long-term health consequences of economic change and inequality.

Does moderate iron deficiency protect against childhood illness? A test of the optimal iron hypothesis in Tanzania.

OBJECTIVES: To test the hypothesis that moderate iron deficiency among children is associated with lower likelihood of infection. MATERIALS AND METHODS: We use data from a population representative cross sectional study of 1164 Tanzanian children aged 6-59 months from the Tanzania Demographic and Health Survey. Respondents' iron levels were assessed through serum transferrin receptor (sTfR) and anemia was assessed using hemoglobin. C-reactive protein (CRP) was used as a marker of infection. RESULTS: Nearly 25% of the children were categorized as normal (iron replete, non-anemic); 45% were IDE (low iron, non-anemic), 24% were classified as IDA (low iron, anemic), and 69 children (5.9%) were anemic but had no evidence of iron deficiency. IDE was not associated with a lower likelihood of elevated CRP compared to iron replete, non-anemic children; 45% of normal children had elevated CRP compared to 51% of IDE children (P = 0.10). IDA, by contrast, was associated with a higher likelihood of elevated CRP (68%, P < 0.001). These results were unchanged when child, maternal, and household controls were added to a logistic regression model. DISCUSSION: Our results do not support the optimal iron hypothesis as conventionally formulated. The fact that we did not find an effect where some other studies have may be due to differences in study design, sample (e.g., age), or the baseline pathogenic ecology. Alternatively, it may be more fruitful to investigate iron regulation as an allostatic system that responds to infections adaptively, rather than to expect an optimal pre-infection value.

Genetic population structure accounts for contemporary ecogeographic patterns in tropic and subtropic-dwelling humans.

Contemporary human populations conform to ecogeographic predictions that animals will become more compact in cooler climates and less compact in warmer ones. However, it remains unclear to what extent this pattern reflects plastic responses to current environments or genetic differences among populations. Analyzing anthropometric surveys of 232,684 children and adults from across 80 ethnolinguistic groups in sub-Saharan Africa, Asia and the Americas, we confirm that body surface-to-volume correlates with contemporary temperature at magnitudes found in more latitudinally diverse samples (Adj. R2 = 0.14-0.28). However, far more variation in body surface-to-volume is attributable to genetic population structure (Adj. R2 = 0.50-0.74). Moreover, genetic population structure accounts for nearly all of the observed relationship between contemporary temperature and body surface-to-volume among children and adults. Indeed, after controlling for population structure, contemporary temperature accounts for no more than 4% of the variance in body form in these groups. This effect of genetic affinity on body form is also independent of other ecological variables, such as dominant mode of subsistence and household wealth per capita. These findings suggest that the observed fit of human body surface-to-volume with current climate in this sample reflects relatively large effects of existing genetic population structure of contemporary humans compared to plastic response to current environments.