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、哺乳和育儿过程中投入大量的热量。有人提出，女性已经进化出了不同的方式来改变他们在生殖上花费的能量，以响应能量的可用性，这通常是由身体脂肪指数。过量的身体脂肪会对生殖激素途径产生不利影响，并扰乱月经周期，目前尚不清楚这是否部分是由于身体脂肪水平对压力敏感性的影响。该研究项目检查了具有相对较高体脂水平的人群中的女性生殖功能，这些人群先前已被证明-与其他人群相比-经历相对较低的月经周期不规则率。除了有助于更好地了解身体脂肪与生殖功能之间的关联的多样性外，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个科学模型来描述卵巢功能和热量能量可用性之间的关系。脂肪抑制模型表明，女性生殖功能与体脂水平密切相关，而代谢模型表明，女性生殖功能更强烈地受到热量能量缺乏的影响。该项目通过以下方式在高体脂水平的女性中测试这些模型：1）在约150名育龄中期女性的研究样本中检查月经不规律和排卵丧失的患病率，以及2）评估月经周期中与体脂水平和体力活动相关的生殖激素水平。通过使用金标准双X射线吸收法来估计皮下脂肪，以及可穿戴的身体活动监测器来量化日常身体活动，该项目可以解决高体脂水平是否可以保护女性生殖功能免受热量需求增加所引起的能量压力的问题。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值进行评估而被认为值得支持和更广泛的影响审查标准。

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.