Two studies of Tsarang village, Upper Mustang Nepal with different results.

The recent Journal of Physiological Anthropology article on polycythemia among Tibetan highlanders (Arima et al., J Physiol Anthropol 43:25, 2024) piqued our interest because we collected similar data in the same Nepali village in Upper Mustang two years later with notably different results (Cho et al., Evol Med Public Health 2017:82-96, 2017; Ye et al., Proc Natl Acad Sci U S A 121:e2403309121, 2024). Arima et al report high prevalences of chronic disease and conclude that Tsarang villagers have poor health. Here, we describe our relevant findings to show that authors' definitions and other research design elements can yield different population health implications. Our study sampled ethnic Tibetan Upper Mustang women 39 Years and older in 2012 who had been married or pregnant and were lifelong residents of this village at 3500m. At our 2019 follow-up study, the women were 46 Years and older. Fifty-five of the 64 eligible Tsarang residents (85%) participated in 2019 study designed to examine the influences of genes and physiology on reproductive success. Arima et al. sampled all Tsarang residents 18 or older in 2017, therefore, our studies include many of the same women in their mid-40s and older. Arima et al reported that 12% of the sample were polycythemic, whereas we found none; they reported 26% obesity whereas we found none; they showed 17% of the sample had hypertension, whereas we found 27%. Factors that may account for the differences in estimates of chronic disease prevalence in Tsarang include age differences in the samples, a wider age range in the currently reported sample, undefined cut-off values for disease categories, while we applied and reported chronic diseases using standard definitions. Because our study did not replicate the findings of Arima et al., we caution against concluding that women in Tsarang have alarming rates of obesity, polycythemia, and hypoxia. Our studies agree that high blood pressure is a public health problem among women in Tsarang. Future use of clear definitions of disease categories will help establish a common understanding of a population's health.