Sakura Oyama

EMAILED: This project examined the association between energy availability and ovarian function among Samoan females, a population with high adiposity levels but previously thought to be relatively protected from obesity-related reproductive dysfunction. In phase one, I prospectively tracked menstrual cycles of n=101 Samoan females aged 25–39 and assessed associations with body composition and metabolic risk. More than 75% of participants had irregular menstrual cycles, and irregularity was associated with central fat distribution and increased diabetes risk. In phase two, I collected daily urine samples across 1-2 menstrual from n=54 females to characterize ovarian hormone patterns. Ongoing hormonal analyses suggest that existing theoretical models do not fully explain patterns of ovarian function in high-obesity contexts. While the lipostatic model predicts a positive relationship between adiposity and reproductive function, preliminary findings – consistent with studies in other settings – indicate that high levels of central adiposity are associated with reduced ovarian function. In contrast, the metabolic model emphasizes ovarian sensitivity to energetic stress. However, I have not yet identified any associations between ovarian function and physical activity. By examining ovarian function at the upper extreme of human adiposity, this study expands our understanding of how evolutionary and contemporary ecological conditions shape female reproductive physiology.