A comparison of physical fitness between Igloolik inuit and Volochanka nGanasan

A Systematic Review of Musculoskeletal Fitness Among Indigenous Populations in North America and Circumpolar Inuit Populations

BACKGROUND

North American indigenous populations experience higher rates of obesity and chronic disease compared with nonindigenous populations. Improvements in musculoskeletal fitness can mitigate negative health outcomes, but is not well understood among indigenous populations. This review examines musculoskeletal fitness measures among North American indigenous populations.

METHODS

A total of 1632 citations were evaluated and 18 studies were included.

RESULTS

Comparisons of musculoskeletal fitness measures between North American indigenous men and boys and women and girls were generally not reported. The greatest left and right combined maximal grip strength and maximal leg strength among Inuit boys and men and girls and women were observed among 20-29 years age group. Maximal combined right and left grip strength declined from 1970 to 1990, by an average of 15% among adults and 10% among youth. Maximal leg extension among Inuit has declined even further, averaging 38% among adults and 27% among youth from 1970 to 1990. Inuit men demonstrate greater grip strength and lower leg strength than Russian indigenous men, whereas Inuit women demonstrate greater leg strength.

CONCLUSIONS

Further research is needed to better understand physical fitness among indigenous peoples and the potential for improving health and reducing chronic disease risk for indigenous peoples through physical fitness.

Ecogeographical associations between climate and human body composition: analyses based on anthropometry and skinfolds

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.

Health consequences of postsocialist transition: Dietary and lifestyle determinants of plasma lipids in Yakutia

The rapid social and cultural changes introduced by the collapse of the Soviet Union have resulted in important differences in cardiovascular health for indigenous Siberians. This study investigated diet and lifestyle determinants of plasma lipids in the Yakut, an indigenous Siberian herding population. The study used a cross-sectional design with data on 201 subjects in three urbanized towns and three rural communities in northeastern Siberia. Data on sociodemographic characteristics, dietary intake, and material lifestyle were collected, and lipids were analyzed from venous whole blood. Diet was analyzed using patterns of dietary intake based on principal components analysis of a dietary intake (food frequency) questionnaire. We identified three diet patterns: a traditional subsistence diet, a market foods diet, and a mixed diet. The effect of lifestyle on cardiovascular risk factors was measured using an ethnographically defined lifestyle index, with two orthogonal dimensions: subsistence lifestyle and modern lifestyle. Total cholesterol (TC) and low-density lipoprotein (LDL) were significantly higher among those consuming a traditional subsistence diet of meat and dairy products. A modern lifestyle was associated with lower TC and LDL but higher adiposity and higher risk of obesity. LDL and TC were higher in rural communities and lower in urbanized towns. The significantly higher lipid levels associated with a subsistence diet and indirectly with a subsistence lifestyle indicate the emergence of a significant health problem associated with the social and cultural changes occurring in Yakutia today. These findings underscore the need for dietary modification and promotion of physical activity among those most at risk for cardiovascular disease (CVD). Moreover, these results differ from those commonly seen in "modernizing" populations, in that elements of subsistence lifestyle are associated with an elevated rather than reduced risk of CVD. Such variable responses to lifestyle change emphasize the need to better understand the distinct social and historical events that may influence health changes among populations in transition.