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

人类生殖需要女性在怀孕、哺乳和育儿上投入大量的卡路里能量。有人提出，女性已经进化出不同的方式来改变她们在生殖上花费的能量，以回应能量的可获得性，这通常是以身体脂肪为指标的。过多的体脂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体脂水平对压力敏感性的影响。这项研究项目考察了体脂水平相对较高的人群中女性的生殖功能，这些女性之前与其他人群相比，经历过相对较低的月经不规律周期。除了有助于更好地了解身体脂肪-生殖功能协会的多样性外，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。生殖生物学家开发了两个科学模型来描述卵巢功能和卡路里能量供应之间的关系。脂肪模型表明女性的生殖功能与身体脂肪水平密切相关，而新陈代谢模型则表明女性生殖功能受热量缺乏的影响更大。该项目在高体脂肪水平的女性中测试这些模型，方法是：1)在约150名中期生殖年龄女性的研究样本中检查月经不规律和排卵丧失的发生率，以及2)评估月经周期中生殖激素水平与体脂水平和体力活动的关系。通过使用黄金标准的双X射线吸收测量仪来估计皮下脂肪，以及可穿戴的体力活动监测器来量化日常体力活动，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卡路里需求增加所造成的能量压力的问题。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.