Tatiana M. Klimova

Seasonal variation in basal metabolic rates among the yakut (Sakha) of Northeastern Siberia

Objectives: Previous research has shown that indigenous circumpolar populations have elevated basal metabolic rates (BMRs), yet few studies have explored whether metabolic rates increase during the winter. This study addresses this gap by examining seasonal variation in BMR and its associations with thyroid function and lifestyle factors among the Yakut (Sakha) of Siberia.

Circumpolar Adaptation, Social Change, and the Development of Autoimmune Thyroid Disorders Among the Yakut (Sakha) of Siberia

Alterations in thyroid function appear to play a central role in adaptation to Arctic environments. Increased thyroid activity in indigenous circumpolar populations is associated with upregulated metabolism, including elevated basal metabolic rate (BMR); however, little is known about the possible health consequences of these climate‐induced changes on thyroid function. The focus of the present study is to determine the prevalence of autoimmune thyroid disorders and their lifestyle and metabolic correlates among a sample of indigenous Yakut adults from northeastern Siberia.

Seasonal and Socioeconomic Influences on Thyroid Function Among the Yakut (Sakha) of Eastern Siberia

Previous research has shown that the extreme cold and short day lengths of polar winters promote increased production and uptake of thyroid hormones, resulting in marked declines in free triiodothyronine (fT3). However, this “polar T3 syndrome” has been documented almost exclusively on small samples of male sojourners and little is known about seasonal changes in thyroid function among indigenous circumpolar groups. The present study addresses this gap by examining seasonal changes in thyroid hormone levels among the indigenous Yakut (Sakha) of northeastern Siberia.

Objectively measured physical activity and sedentary behaviour of Yakut (Sakha) adults.

Abstract Background: Circumpolar regions are undergoing social and economic transition, which often corresponds to a behavioural transition. Yet, physical activity and sedentary behaviour are rarely objectively measured within these groups. Aim: This study aimed to characterize objectively measured physical activity and sedentary behaviour in a sample of indigenous Siberians. Subjects and methods: Yakut (Sakha) adults (n = 68, 32 men) underwent anthropometry, interviews and wore a triaxial accelerometer for two days. Time spent in moderate-to-vigorous physical activity (MVPA) or sedentary behaviour was calculated using a single axis and also all three axes. Results: Men spent significantly more time in MVPA than women, although no sex difference was found in sedentary behaviour. Participants were far more active and less sedentary when classified using all three axes (vector magnitude) than a single axis. Television viewing time significantly related to sedentary behaviour in men only. Conclusion: The Yakut have gender differences in amount and predictors of physical activity and sedentary behaviour. Triaxial accelerometry is more sensitive to daily physical activity in free living populations than single axis.

Do physical activity and sedentary behavior relate to cardio-metabolic risk factor clustering in indigenous Siberian adults?

To investigate whether having multiple risk factors for cardio‐metabolic disease is associated with objectively measured physical activity or sedentary behavior within a sample of Yakut (Sakha) of Siberia.

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

Among indigenous circumpolar populations, extreme seasonality influences food availability and energy metabolism. Furthermore, subsistence patterns and wage labor opportunities shift with season. Thus, health measures among circumpolar populations likely exhibit seasonal changes that are influenced by lifestyle factors. This study examines how markers of cardio‐metabolic health vary between summer and winter as a function of an individuals lifestyle and sex among the Yakut of northeastern Siberia.

Socio‐demographic predictors of sleep complaints in indigenous Siberians with a mixed economy

ABSTRACT Objectives: Socio‐demographic indicators closely relate to sleep in industrialized populations. However we know very little about how such factors impact sleep in populations undergoing industrialization. Within populations transitioning to the global economy, the preliminary evidence has found an inconsistent relationship between socio‐demographics and sleep complaints across countries and social strata. Materials and methods: Surveys were conducted on a sample of rural Sakha (Yakut) adults (n = 168) during the autumn of 2103 to assess variation in socio‐demographics and sleep complaints, including trouble sleeping and daytime sleepiness. Socio‐demographic variables included age, gender, socioeconomic measures, and markers of traditional/market‐based lifestyle. We tested whether the socio‐demographic variables predicted sleep complaints using bivariate analyses and multiple logistic regressions. Results: Trouble sleeping was reported by 18.5% of the participants and excessive daytime sleepiness (EDS) by 17.3%. Trouble sleeping was significantly predicted by older age, female gender, and mixing traditional and market‐based lifestyles. EDS was not significantly predicted by any socio‐demographic variable. Discussion: These findings support the few large‐scale studies that found inconsistent relationships between measures of socioeconomic status and sleep complaints in transitioning populations. Employing a mix of traditional and market‐based lifestyles may leave Sakha in a space of vulnerability, leading to trouble sleeping. Am J Phys Anthropol 157:641–647, 2015.

Brown adipose tissue, energy expenditure, and biomarkers of cardio-metabolic health among the Yakut (Sakha) of northeastern Siberia

This study provides the first investigation of non‐shivering thermogenesis (NST) and brown adipose tissue (BAT) activity among an indigenous circumpolar population, the Yakut of northeastern Siberia. The study also examines the health significance of BAT activity in this population by testing the relationships between BAT thermogenesis and biomarkers of cardio‐metabolic disease risk, such as percent body fat and blood glucose and cholesterol levels.

Adiponectin, hemoglobin, and cardiovascular risk in an indigenous siberian population

Adipose tissue hypoxia appears to play a role in promoting chronic inflammation and the development of obesity‐related cardiovascular and metabolic diseases, yet the underlying mechanisms are not well understood. The aim of the present research is to examine whether adiponectin levels (an adipocyte‐derived hormone with anti‐inflammatory properties) are inversely correlated with hemoglobin levels in an indigenous Siberian population.