Doctoral Dissertation Research: Female reproductive ecology and energy availability in a high adiposity human population

人类的生殖需要女性在怀孕、哺乳和育儿方面投入大量的热量。有人提出，女性已经进化出了不同的方式来改变她们在生殖上花费的能量，以回应能量的可用性，这通常是由身体脂肪来指示的。过多的体脂会对生殖激素通路产生不利影响，扰乱月经周期，目前尚不清楚这是否部分归因于体脂水平对压力敏感性的影响。这一研究项目考察了身体脂肪水平相对较高的女性的生殖功能，与其他人群相比，这些女性的月经周期不规则率相对较低。除了有助于更好地了解身体脂肪与生殖功能之间的关系的多样性外，该项目还支持对研究界的女研究生和科学家进行科学培训，并帮助加强与当地社区的科学伙伴关系。生殖生物学家已经开发了两种科学模型来描述卵巢功能和热量可用性之间的关系。脂肪代谢模型表明，女性生殖功能与体脂水平密切相关，而代谢模型表明，女性生殖功能受热量缺乏的影响更大。本项目在高体脂水平的女性中测试这些模型：1)在大约150名育龄中期女性的研究样本中检查月经不规律和排卵减少的普遍程度；2)评估整个月经周期中生殖激素水平与体脂水平和身体活动的关系。通过使用金标准双x线吸收仪来估计皮下脂肪，并使用可穿戴式身体活动监测仪来量化日常身体活动，该项目可以解决高体脂水平是否保护女性生殖功能免受热量需求增加引起的能量压力的问题。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Human reproduction requires females to invest significant amounts of caloric energy into pregnancy, lactation, and childcare. It has been proposed that females have evolved ways to vary how much energy they spend on reproduction in response to energy availability, which has commonly been indexed by body fat. Excess body fat can adversely affect reproductive hormone pathways and disrupt menstrual cycles, and it is not clear whether this might in part be due to the influence of body fat levels on sensitivity to stress. This research project examines female reproductive function among women in a population with comparatively high body fat levels who have been shown previously - in contrast to other populations - to experience relatively low rates of irregular menstrual cycles. In addition to contributing to a greater understanding of the diversity of body fat-reproductive function associations, this project supports scientific training for female graduate students and scientists in the research community, and helps strengthen scientific partnerships with local communities. Reproductive biologists have developed two scientific models to describe the relationship between ovarian function and caloric energy availability. The Lipostatic Model suggests that female reproductive function is closely associated with body fat levels, while the Metabolic Model suggests that female reproductive function is more strongly affected by caloric energy deficiencies. This project tests these models among females with high body fat levels by 1) examining the prevalence of menstrual irregularity and loss of ovulation among a study sample of approximately 150 females of mid-reproductive age, and 2) assessing reproductive hormone levels across the menstrual cycle in relation to body fat levels and physical activity. By using gold-standard dual x-ray absorptiometry to estimate subcutaneous fat together with wearable physical activity monitors to quantify daily physical activity, the project can address the question of whether high body fat levels protect female reproductive function from energetic stress caused by increased caloric demands.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.