Lifestyle mediates seasonal changes in metabolic health among the yakut (sakha) of northeastern siberia

The built environment is more predictive of cardiometabolic health than other aspects of lifestyle in two rapidly transitioning Indigenous populations

Background

Many subsistence-level and Indigenous societies around the world are rapidly experiencing urbanization, nutrition transition, and integration into market-economies, resulting in marked increases in cardiometabolic diseases. Determining the most potent and generalized drivers of changing health is essential for identifying vulnerable communities and creating effective policies to combat increased chronic disease risk across socio-environmental contexts. However, comparative tests of how different lifestyle features affect the health of populations undergoing lifestyle transitions remain rare, and require comparable, integrated anthropological and health data collected in diverse contexts.

Methods

We developed nine scales to quantify different facets of lifestyle (e.g., urban infrastructure, market-integration, acculturation) in two Indigenous, transitioning subsistence populations currently undergoing rapid change in very different ecological and sociopolitical contexts: Turkana pastoralists of northwest Kenya (n = 3,692) and Orang Asli mixed subsistence groups of Peninsular Malaysia (n = 688). We tested the extent to which these lifestyle scales predicted 16 measures of cardiometabolic health and compared the generalizability of each scale across the two populations. We used factor analysis to decompose comprehensive lifestyle data into salient axes without supervision, sensitivity analyses to understand which components of the multidimensional scales were most important, and sex-stratified analyses to understand how facets of lifestyle variation differentially impacted cardiometabolic health among males and females.

Findings

Cardiometabolic health was best predicted by measures that quantified urban infrastructure and market-derived material wealth compared to metrics encompassing diet, mobility, or acculturation, and these results were highly consistent across both populations and sexes. Factor analysis results were also highly consistent between the Turkana and Orang Asli and revealed that lifestyle variation decomposes into two distinct axes-the built environment and diet-which change at different paces and have different relationships with health.

Interpretation

Our analysis of comparable data from Indigenous peoples in East Africa and Southeast Asia revealed a surprising amount of generalizability: in both contexts, measures of local infrastructure and built environment are consistently more predictive of cardiometabolic health than other facets of lifestyle that are seemingly more proximate to health, such as diet. We hypothesize that this is because the built environment impacts unmeasured proximate drivers like physical activity, increased stress, and broader access to market goods, and serves as a proxy for the duration of time that communities have been market-integrated.

Seasonal variability in body mass index, waist circumference, and skinfolds in Norwegian children

OBJECTIVES

Studies have shown that children develop a higher body weight during summer months. This has been demonstrated repeatedly using the body mass index (BMI), but the effect of season on other weight-related anthropometric measurements is still unclear.

METHODS

Measurements of height, weight, waist circumference (WC), triceps, and subscapular skinfolds (TSF and SSF), collected from September till May in a cross-sectional sample of 4-16-year-old children and adolescents (n = 4525) from the Bergen Growth Study 1 (BGS1). Differences in z-score by season were tested with linear models adjusted for age group and separately for sex. Overall differences were tested with a one-way between-group analysis of variance.

RESULTS

The girls had higher BMIz (+0.12, p = .03) and WCz (+0.18, p = .002) in fall compared with spring. TSFz (-0.19, p < .001) and SSFz (-0.18, p < .001) were lower in winter in girls, and in boys both in fall (TSFz -0.10, p = .046; SSFz - 0.16, p < .001), and winter (TSFz -0.15, p = .004; SSFz -0.14, p = .003), when compared with spring.

CONCLUSIONS

Seasonal variation was detected for all anthropometric measures, but differences in the direction of the effect between measures of global (BMI), central (WC) or subcutaneous (SF) adiposity suggest a more complex mechanism that needs further exploration.

Human cold adaptation: An unfinished agenda v2.0

BACKGROUND

Research on human extreme cold climate adaptations has benefitted from a recent resurgence since Ted Steegmann laid out his Human Cold Adaptation Agenda in 2007. Human biologists have drastically expanded our knowledge in this area during the last 15 years, but we still have a great deal more work to do to fulfill the cold climate adaptation agenda.

METHODS

Here, I follow Steegmann's example by providing a review of cold climate adaptations and setting forth a new, expanded agenda.

RESULTS

I review the foundational work on cold climate adaptations including classic Bergmann, Allen, and Thomson rules as well as early work assessing metabolic differences among Indigenous cold climate populations. From there, I discuss some of the groundbreaking work currently taking place on cold climate adaptations such as brown adipose tissue (a heat generating organ), physical activity levels, metabolic rates, and behavioral/cultural mechanisms. Finally, I present a path forward for future research with a focus on some of the basic extreme cold adaptations as well as how human biologists should approach the effects of climate change on human health and well-being, particularly within a cold climate context.

CONCLUSION

The Arctic has felt the dramatic effects of climate change sooner and more acutely than other parts of the world, making it an ideal location for studying both cold climate adaptations and climate change resilience. Human biologists have a great deal to contribute to the conversation on not only adaptations to extreme cold, but also the ways in which climate change is being embodied by cold climate populations.

Pearl Memorial Lecture. Humans at the extremes: Exploring human adaptation to ecological and social stressors

The field of human biology has long explored how human populations have adapted to extreme environmental circumstances. Yet, it has become increasingly clear that conditions of social stress, poverty, and lifestyle change play equally important roles in shaping human biological variation and health. In this paper, I provide a brief background on the foundational human adaptability research of the International Biological Programme (IBP) from the 1960s, highlighting how its successes and critiques have shaped current research directions in the field. I then discuss and reflect on my own field research that has examined the influence of both environmental and social stresses on human populations living in different ecosystems: the Peruvian Andes, the Siberian arctic, and the Bolivian rainforest. Finally, I consider how the papers in this special issue advance our understanding of human adaptability to extreme conditions and offer directions for future research. Drawing on our field's distinctive evolutionary and biocultural perspectives, human biologists are uniquely positioned to examine how the interplay between social and ecological domains influences the human condition.

Human adaptation to cold and warm climatic conditions: A comparison between two geographically diverse Indigenous populations

OBJECTIVES

The present study aims to compare body adiposity and blood pressure (BP) in two climatically and ethnically diverse populations, examining whether thermoregulatory adaptive mechanism may protect Indigenous populations from exhibiting adverse consequences of increased adiposity.

METHODS

A cross sectional sample of 404 subjects, of which 200 were Monpa and 204 were Santhal, from two ethnically and geographically distinct populations of India were studied. Body mass index (BMI; kg/m2 ), fat mass (FM; kg), fat free mass (kg), and percent body fat (%BF) were calculated for evaluation of body adiposity. Multivariate multiple regression analysis was adopted to examine the influence of age and sex of populations under study, on body adiposity and BP variables.

RESULTS

BMI, %BF, and FM were found to be significantly higher (p ˂ .001) among the Monpa males and females compared with their Santhal counterparts. In contrast, the prevalence of hypertension among Monpa and Santhal is comparable (3.5%Monpa vs. 3.9%Santhal for systolic BP; 8.5%Monpa vs. 8.3%Santhal for diastolic BP). Adiposity, as quantitated by the fat mass index and %BF was significantly (p ˂ .001) correlated to age and sex of study population, explaining ~75.3% and ~75.4% of total variations of these variables, respectively.

CONCLUSIONS

Overall the present study suggests that modern human populations follow thermoregulatory mechanism for adaptation to different climatic conditions. Consequently, greater adiposity was evident among the Monpa who adapt to the cold climate, in comparison to their Santhal counterparts who dwell in warm climate.

To the extreme! How biological anthropology can inform exercise physiology in extreme environments

The fields of biological anthropology and exercise physiology are closely related and can provide mutually beneficial insights into human performance. These fields often use similar methods and are both interested in how humans function, perform, and respond in extreme environments. However, these two fields have different perspectives, ask different questions, and work within different theoretical frameworks and timescales. Biological anthropologists and exercise physiologists can greatly benefit from working together when examining human adaptation, acclimatization, and athletic performance in the extremes of heat, cold, and high-altitude. Here we review the adaptations and acclimatizations in these three different extreme environments. We then examine how this work has informed and built upon exercise physiology research on human performance. Finally, we present an agenda for moving forward, hopefully, with these two fields working more closely together to produce innovative research that improves our holistic understanding of human performance capacities informed by evolutionary theory, modern human acclimatization, and the desire to produce immediate and direct benefits.

No association of BMI and body adiposity with cardiometabolic biomarkers among a small sample of reindeer herders of sub-Arctic Finland

The rising global obesity rate is alarming due to its real health and socioeconomic consequences. Finland, like other circumpolar regions, is also experiencing a rise in obesity . Here we assess BMI, body adiposity, and measures of cardiometabolic health among a small population of reindeer herders in sub-Arctic Finland. We collected anthropometric and biomarker measures at two different time points: October 2018 (N = 20) and January 2019 (N = 21) with a total of 25 unique individuals across the data collection periods (ages 20-64). Anthropometric measures included height, weight, age, and body composition. Biomarkers included measures of cholesterol, fasting glucose, HDL cholesterol, LDL cholesterol, and triglyceride levels. Over 70% of this sample was classified as "overweight" and "obese" as categorised by BMI and 64% classified as "overfat" based on body fat percentage. However, there was no significant relationship between BMI and body fat percentage with any of the measured biomarkers. Although the sample size is small, the results of this study suggest there might not be a strong correlation between BMI, body adiposity, and cardiometabolic health indices within this population - a pattern that has been documented elsewhere. However, further study is needed to confirm this lack of a correlation.

Age‐related features of the content of substrates of energy metabolism and body mass index in women residing in the S ubarctic and A rctic regions of R ussia

OBJECTIVES

Age is associated with a number of health risks linked to obesity caused by an imbalance in the main energy substrates-fatty acids (FA) and glucose (Glu). Therefore, the objective of this study was to identify age-related features of the metabolism of fatty acids and Glu, their correlations and the relation with the body mass index (BMI) in women of the local Caucasoid population from two northern regions of Russia with different nature, climate, and geography.

METHODS

We examined women aged 21-60 years born and permanently residing in the Subarctic region (SR) and the Arctic region (AR). The participants were divided into three age groups: 21-35, 36-45, and 46-60 years. The levels of FAs, Glu, and triglycerides (TG) in the blood serum were determined by spectrophotometric and gas chromatographic methods; the values of BMI and TyG (triglyceride glucose) index were calculated. To analyze data, we used the descriptive and correlation analyses by nonparametric methods, as well as multiple linear regression analysis.

RESULTS

With age, the surveyed women demonstrated elevated levels of triglyceride, the majority of the studied fatty acids, BMI and TyG index. For three fatty acids, age-related changes were noted in one of the regions only: stearic and linoleic acids in the SR, and docosahexaenoic acid in the AR; no significant changes were observed for dihomo-γ-linolenic and arachidonic acids. We found elevated Glu levels in women aged 46-60 years residing in the SR. Regional differences were due to higher concentrations of FAs and Glu in the AR. All identified correlations were positive. BMI values were associated with FAs and TG, and in women aged 46-60 years, they were additionally associated with Glu. The latter also correlated with some FAs and TG in this group. TyG index associations with saturated FAs (SFAs) became stronger with age.

CONCLUSIONS

Age has a significant impact on the homeostasis of key energy substrates (Glu, TG, SFAs, monounsaturated FAs), on BMI and TyG index, which are indicators of obesity and insulin resistance. Depending on the region of residence (Subarctic or Arctic), we found changes in the FA profile undersaturation (especially long-chain polyunsaturated FAs) and some specific features of Glu homeostasis (for the age groups of 21-35 and 46-60 years) in women of Caucasoid race in the Russian North. Multiple regression analysis showed that BMI, as well as the region of residence and age, are significant predictors for almost all biochemical parameters, especially for TG and TyG index.

Bringing the lab bench to the field: Point-of-care testing for enhancing health research and stakeholder engagement in rural/remote, indigenous, and resource-limited contexts

Point-of-care testing (POCT) allows researchers and health-care providers to bring the lab bench to the field, providing essential health information that can be leveraged to improve health care, accessibility, and understanding across clinical and research settings. Gaps in health service access are most pronounced in what we term RIR settings-rural/remote regions, involving Indigenous peoples, and/or within resource-limited settings. In these contexts, morbidity and mortality from infectious and non-communicable diseases are disproportionately higher due to numerous geographic, economic, political, and sociohistorical factors. Human biologists and global health scholars are well-positioned to contribute on-the-ground-level insights that can serve to minimize global health inequities and POCT has the potential to augment such approaches. While the clinical benefits of POCT include increasing health service access by bringing testing, rapid diagnosis, and treatment to underserved communities with limited pathways to centralized laboratory testing, POCT also provides added benefits to both health-focused researchers and their participants. Through portable, minimally invasive devices, researchers can provide actionable health data to participants by coupling POCT with population-specific health education, discussing results and their implications, creating space for participants to voice concerns, and facilitating linkages to treatment. POCT can also strengthen human biology research by shedding light on questions of evolutionary and biocultural importance. Here, we expand on the epidemiological and research value, as well as practical and ethical challenges of POCT across stakeholders (i.e., participant, community, health researcher, and trainee). Finally, we emphasize the immense opportunities of POCT for fostering collaborative research and enhancing access to health delivery and information and, by extension, helping to mitigate persistent global health inequities.

Dependence of Seasonal Dynamics in Healthy People's Circulating Lipids and Carbohydrates on Regional Climate: Meta-Analysis

We analyzed the seasonal dynamics of lipid profile, glucose, and insulin in healthy subjects from 29 studies conducted in 23 regions, located in different climate zones ranging from subarctic to tropical. Our meta-analysis showed that people have higher the level of TC (total cholesterol), LDL (low-density lipoprotein), HDL (high-density lipoprotein), FBG (fasting blood glucose) in winter than in summer regardless of gender. Regional climate had a significant impact on the seasonal dynamics of lipid profile and glucose. TC, HDL, FBG seasonal fluctuations were more prominent in a climate that had a marked increase in average monthly atmospheric pressure in winter compared with summer as opposed to a climate where atmospheric pressure did not vary significantly in winter and summer. In a climate with humid winters, TC seasonal changes were significantly greater than in the regions with humid summers, most likely due to LDL seasonal changes, since HDL seasonal dynamics with peaks in winter were more prominent in the regions with humid summers. The level of triglycerides had prominent seasonal dynamics with peak values in winter only in the regions with a large difference in winter and summer air temperatures. The results of our current and prior meta-analysis allow for the conclusion that the seasonal dynamics of circulating lipids and glucose are frequently linked to the seasonal dynamics of thyroid-stimulating hormone and hematocrit. Dependence of the seasonal changes in the biochemical parameters on annual fluctuations in air temperature, atmospheric pressure and relative humidity is more obvious than on photoperiod changes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12291-022-01064-6.

Data mining: traditional spring festival associated with hypercholesterolemia

BACKGROUND

Serum lipid concentrations are affected by long-term high-fat diets; thus, we hypothesize that lipid levels increase after the Spring Festival in China.

METHOD

In total, 20,192 individuals (male: n=10,108, female: n=10,084) were enrolled in this retrospective cross-sectional study based on clinical data from the Laboratory Information System (LIS) and Hospital Information System (HIS) in Peking Union Medical College Hospital from 2014 to 2018. Total cholesterol (TC), triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were analyzed.

RESULTS

The serum TC [male vs. female: (4.71 ± 0.90 vs. 4.56 ± 0.85) mmol/L], TG [male vs. female: (1.71 ± 1.56 vs. 1.02 ± 0.68) mmol/L], and LDL-C [male vs. female: (3.01 ± 0.77 vs. 2.73 ± 0.74) mmol/L] levels were significantly higher in males than in females (P < 0.001); serum HDL-C [male vs. female: (1.18 ± 0.28 vs. 1.50 ± 0.34) mmol/L] was significantly lower in males (P < 0.001). In February, the TC, TG, and LDL-C levels were 8.4%, 16.3%, and 9.3% higher than the lowest levels recorded, respectively. The prevalence of dyslipidemia of the two weeks before the Spring festival was significantly lower than that of the first week after the Spring festival (43.6% (168/385) vs. 54.1% (126/233), P=0.007). Additionally, the prevalence of dyslipidemia was statistically higher in the first week after the Spring Festival than in May-January.

CONCLUSION

Higher TC, TG, and LDL-C in winter could be associated with high-fat diets during the Spring Festival. The Spring Festival was immediately followed by a higher lipid concentrations. Thus, we don't recommend lipid assessment or physical examination immediately after the holiday especially Spring festival.

Reindeer herders from subarctic Finland exhibit high total energy expenditure and low energy intake during the autumn herd roundup

OBJECTIVE

High levels of total energy expenditure (TEE, kcal/day) have been documented among numerous human populations such as tropical climate horticulturalists and high-altitude agriculturalists. However, less work has been conducted among highly physically active cold climate populations.

METHODS

In October 2018, TEE was measured using the doubly labeled water (TEE_DLW , N = 10) and flex-heart rate methods (TEE_HR , N = 24) for 6-14 days among reindeer herders (20-62 years) in northern Finland during an especially physically demanding, but not seasonally representative, period of the year for herders-the annual reindeer herd roundup. Self-reported dietary intake was also collected during TEE measurement periods. TEE was then compared to that of hunter gatherer, farming, and market economies.

RESULTS

During the herd roundup, herders expended a mean of 4183 ± 949 kcal/day as measured by the DLW method, which was not significantly different from TEE_HR . Mean caloric intake was 1718 ± 709 kcal/day, and was significantly lower than TEE_DLW and TEE_HR (p < .001). Herder TEE_DLW was significantly higher than that of hunter gatherer (p = .0014) and market (p < .0014) economy populations; however, herder TEE_DLW was not different from that of farming populations (p = .91).

CONCLUSION

High TEE and low caloric intake among herders reflect the extreme demands placed on herders during the annual herd round up. Although TEE_DLW was similar between cold climate herders and hot climate farming populations, there are likely differences in how that TEE is comprised, reflecting the local ecologies of these populations.

Biocultural approaches to transgender and gender diverse experience and health: Integrating biomarkers and advancing gender/sex research

Transgender and gender diverse (TGD) people are increasingly visible in U.S. communities and in national media. With this increased visibility, access to gender affirming healthcare is also on the rise, particularly for urban youth. Political backlash and entrenchment in a gender binary, however, continue to marginalize TGD people, increasing risk for health disparities. The 2016 National Institute of Health recognition of sexual and gender minority people as a health disparities population increases available funding for much-needed research. In this article, we speak to the need for a biocultural human biology of gender/sex diversity by delineating factors that influence physiological functioning, mental health, and physical health of TGD people. We propose that many of these factors can best be investigated with minimally invasively collected biomarker samples (MICBS) and discuss how to integrate MICBS into research inclusive of TGD people. Research use of MICBS among TGD people remains limited, and wider use could enable essential biological and health data to be collected from a population often excluded from research. We provide a broad overview of terminology and current literature, point to key research questions, and address potential challenges researchers might face when aiming to integrate MCIBS in research inclusive of transgender and gender diverse people. We argue that, when used effectively, MICBS can enhance human biologists' ability to empirically measure physiology and health-related outcomes and enable more accurate identification of pathways linking human experience, embodiment, and health.

Doing biocultural anthropology: Continuity and change

Biocultural anthropology has long represented an important approach in the study of human biology. However, despite demonstrated utility, its somewhat amorphous identity leaves some scholars questioning just what it means to be biocultural. In this article, rather than providing proscriptive doctrine, we contribute to these conversations about the nature of biocultural anthropology by considering what biocultural research does. We begin with a consideration of some of the foundational themes of biocultural work including recognition of the dialectical nature of sociocultural and biological forces, interest in inequality, and incorporation of both evolutionary and political economic perspectives. To emphasize the consistency of biocultural work over time, we also trace these themes from originating work to their appearance in current research. We then identify some of the key actions of the biocultural approach, noting that biocultural work can execute any number though rarely all of these actions simultaneously. We then offer brief introductions to the articles that make up this special issue, highlighting the ways in which each piece undertakes key biocultural actions. Following these introductions, we provide a discussion of some of the types of biocultural work that are not present in this special issue, recognizing the breadth of biocultural research across multiple subfields of anthropology. Finally, we point to some potentially fruitful directions for future biocultural research. In the end, we conclude that while biocultural anthropology may not have a cohesive or set agenda, it does have a clear and recognizable form of content and methodology illuminated by its actions.

Seasonal variation of body weight loss after bariatric surgery

Seasonal variations have been described in humans in several variables such as sleep, mood, appetite, food preferences, or body weight. We hypothesized that these variations could also influence the decrease in body weight rate in patients submitted to body weight loss interventions. Thus, here we tested the variations of weight loss according to the time of the year the surgery took place in a group patients (n = 1322) submitted to bariatric surgery in the Hospital Universitari de la Vall d'Hebron in Barcelona (geographical coordinates: 41°25'41″N 2°8'32″E). For the analysis, the percentage of total body weight loss (%TWL), excess body weight loss (%EWL) and percentage of body mass index loss (%BMIL) were calculated at 3 (n = 1255), 6 (n = 1172), 9 (n = 1002), and 12 months (n = 1076) after surgery. For %EWL and %BMIL a statistically significant seasonal variation was detected when the variables were calculated at 3 months, but not at the other times, with more weight loss in summer-fall. However, seasonal variations were not detected for %TWL (p = 0.09). The mean amplitude of the seasonal rhythm for %EWL was of 1.8%, while for the rhythm of %BMIL was 0.7%. Moreover, a second peak was detected in January-February modulating the seasonal rhythm of the two variables. Results confirm seasonal variations in humans and indicate that short term responses to weight loss can be modulated by the time of year.