Doctoral Dissertation Research: Investigating the social and developmental determinants of vitamin D production

Northwestern University, Evanston IL

Investigators

Abstract

Vitamin D is vital to the function of several organs and tissues, with decreased vitamin D levels hypothesized to be a contributing factor in several disease processes. Populations in higher latitudes are more likely to have vitamin D deficiencies due to lack of sun exposure; however, recent research indicates that vitamin D deficiency has become a global phenomenon, even in countries near the equator, with women often experiencing more severe deficiency. This doctoral dissertation project applies a biocultural perspective on vitamin D production from infancy through young adulthood to investigate how societal practices and norms create and dictate the physical environments that individuals experience. By using a longitudinal data set, the study delves deeper into the possible factors that contribute to vitamin D deficiency in both men and women, and for societies undergoing urbanization. The project not only addresses the complex interplay of human biology and culture, but also has the potential to inform public health efforts to understand and address vitamin D deficiency. Biological anthropology has elaborated the tradeoffs between the need for vitamin D production and the need to avoid damage from the harmful effects of exposure to ultraviolet rays, but unanswered questions remain regarding how vitamin D is regulated and why some individuals are at risk for vitamin D deficiency. The primary focus has been on sun exposure, but other aspects of the current environment, and aspects of the environment experienced early in life, may be equally important. This study will use longitudinal data collected from the Cebu Longitudinal Health and Nutrition Survey in the Philippines to assess the effects of rapid urbanization and socioeconomic change on vitamin D production in young adulthood. A range of environmental factors early in development, and in adulthood, will be tested as predictors of circulating vitamin D. Furthermore, DNA methylation - an epigenetic process that is associated with gene expression - will be measured at sites in genes associated with vitamin D production. DNA methylation is a plausible mechanism through which environments during development can regulate genome activity in adulthood, and the study will investigate the association between environments in childhood, DNA methylation of vitamin D genes, and vitamin D production in adulthood. The use of a biocultural anthropological approach allows for an exploration of how lived experience affects vitamin D production and well-being over the life course. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.