Growth and fitness of Canadian inuit: Secular trends, 1970-1990

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.

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.

Ultra-endurance athletic performance suggests that energetics drive human morphological thermal adaptation

Both extinct and extant hominin populations display morphological features consistent with Bergmann's and Allen's Rules. However, the functional implications of the morphologies described by these ecological laws are poorly understood. We examined this through the lens of endurance running. Previous research concerning endurance running has focused on locomotor energetic economy. We considered a less-studied dimension of functionality, thermoregulation. The performance of male ultra-marathon runners (n = 88) competing in hot and cold environments was analysed with reference to expected thermoregulatory energy costs and the optimal morphologies predicted by Bergmann's and Allen's Rules. Ecogeographical patterning supporting both principles was observed in thermally challenging environments. Finishers of hot-condition events had significantly longer legs than finishers of cold-condition events. Furthermore, hot-condition finishers had significantly longer legs than those failing to complete hot-condition events. A degree of niche-picking was evident; athletes may have tailored their event entry choices in accordance with their previous race experiences. We propose that the interaction between prolonged physical exertion and hot or cold climates may induce powerful selective pressures driving morphological adaptation. The resulting phenotypes reduce thermoregulatory energetic expenditure, allowing diversion of energy to other functional outcomes such as faster running.

Secular trends are associated with the demographic and epidemiologic transitions in an indigenous community in Oaxaca, Southern Mexico

OBJECTIVE

To test the hypothesis that secular changes in body size and age at menarche are related to the demographic and epidemiologic transitions in an indigenous community in Oaxaca, southern Mexico.

METHODS

Data were derived from surveys of a Zapotec-speaking community conducted between 1968 and 2000. Segmented linear regressions of height, weight, BMI and recalled age at menarche on year of birth in cohorts of adults born before and after the demographic transition were used to evaluate secular changes. Corresponding comparisons of body size (MANCOVA controlling for age) and age at menarche (status quo, probit analysis) were done for samples of children and adolescents born before and after the epidemiological transition.

RESULTS

Height and weight increased in adults born after the demographic transition (mid-1950s), and especially in children and adolescents born after the epidemiological transition (mid-1980s). Age at menarche also decreased significantly in women born after the demographic transition, but at a more rapid estimated rate in adolescents born after the epidemiological transition. Secular gains in body weight were proportional to those for height among children and adolescents, but adults, males more so than females, gained proportionally more weight.

CONCLUSIONS

The secular trend in height in adults of both sexes was associated with the decade of the demographic transition in the mid-1950s. Significant secular gains in size attained and age at menarche occurred in children and youth born after the epidemiologic transition which likely reflected improved health and nutritional conditions since the mid-1980s.

[Physical activity among aboriginals in Canada]

This paper summarizes available information on patterns of physical activity, their determinants and consequences, and the results of various interventions designed to increase the physical activity of Aboriginal peoples in Canada and the United States. There is a paucity of national data on this issue for Aboriginal peoples. The most recent data, from the First Nations Regional Longitudinal Health Survey of 2002-2003, indicate that 21% of adults (27% of men, 15% of women) were engaging in at least 30 min of moderate to vigorous physical activity on 4 d/week or more. The present paper highlights the unique challenges this group faces, underlining the need to integrate collective knowledge regarding how much physical activity is required for Aboriginal Canadians, and how this activity should be accomplished, to promote and maintain health. Efforts are currently underway to tailor Canada's physical activity guide for First Nations, Inuit, and Métis. Future research among Aboriginal groups should examine the minimal and optimal levels of physical activity required to achieve health benefits.

Physical activity of Aboriginal people in CanadaThis article is part of a supplement entitled Advancing physical activity measurement and guidelines in Canada: a scientific review and evidence-based foundation for the future of Canadian physical activity guidelines co-published by Applied Physiology, Nutrition, and Metabolism and the Canadian Journal of Public Health. It may be cited as Appl. Physiol. Nutr. Metab. 32(Suppl. 2E) or as Can. J. Public Health 98(Suppl. 2)

This paper summarizes available information on patterns of physical activity, their determinants and consequences, and the results of various interventions designed to increase the physical activity of Aboriginal peoples in Canada and the United States. There is a paucity of national data on this issue for Aboriginal peoples. The most recent data, from the First Nations Regional Longitudinal Health Survey of 2002–2003, indicate that 21% of adults (27% of men, 15% of women) were engaging in at least 30 min of moderate to vigorous physical activity on 4 d/week or more. The present paper highlights the unique challenges this group faces, underlining the need to integrate collective knowledge regarding how much physical activity is required for Aboriginal Canadians, and how this activity should be accomplished, to promote and maintain health. Efforts are currently underway to tailor Canada’s physical activity guide for First Nations, Inuit, and Métis. Future research among Aboriginal groups should examine the minimal and optimal levels of physical activity required to achieve health benefits.

The great transformation: a long-run perspective on physical well-being in Canada

During the 19th century the physical stature of the Canadian-born stagnated or declined slightly in spite of a substantial increase in income. Stature varied regionally within Canada. The Quebec population was especially short; men in the Atlantic coastal region were taller than their low incomes would lead us to expect. Heights increased dramatically in the 20th Century. The pattern of long-run change is consistent with evidence of age-specific mortality and with the relationship between income and physical well-being envisaged by Preston [Preston, S., 1975. The changing relationship between mortality and the level of economic development. Popul. Stud. 29, 231-248]. The transition from stagnant or declining stature to secular increase points to a dramatic shift ca. 1900 in the evolution of the physical standard of living in Canada.

Body size and physique among Canadians of First Nation and European ancestry

The purpose of this study was to compare body size and physique among Canadians of Aboriginal (First Nation [FN]) and European ancestry (EA) from the northern Ontario communities of Temagami and Bear Island. The sample consisted of 130 FN and 494 EA participants including adults (20-75 years: 214 men, 234 women) and youth (5-19 years: 97 boys, 79 girls). Indicators of body size and physique included stature, the sitting height-to-stature ratio (SSR), body mass, BMI, estimated upper-arm muscle area, biacromial, bicristal, biepicondylar, and bicondylar breadths, and the Heath-Carter anthropometric somatotype (endomorphy, mesomorphy, and ectomorphy). There were few differences in body size between FN and EA, with the exception of adult females. Adult FN females were significantly heavier and had greater bone breadths than EA women (P < 0.001). On the other hand, somatotype differed significantly between EA and FN by age and sex, except for 5-19-year-old females. Among boys and men, FN had greater endomorphy (P < 0.03), whereas FN men also had lower ectomorphy (P < 0.01). Among women, FN were significantly more endomorphic and mesomorphic and less ectomorphic (P < 0.001). Although results for 5-19-year-old females were not significant, they were in the same direction as the other groups (greater endomorphy). Forward stepwise discriminant function analyses indicated that endomorphy was the most important discriminator between FN and EA by age and sex.