Statistical Modeling of Human Fecundity

该项目的动机是在Despr已经和正在进行的各种怀孕研究。这些研究包括纽约州Angler队列预期怀孕研究，生理和感知的心理社会压力对怀孕时间的影响，以及生育力和环境(LIFE)纵向调查研究(PI，流行病学科的G.Buck Louis博士)。 受孕能力(Gini，1926)被定义为在月经周期内没有避孕措施而有规律性行为的夫妇受孕的概率。生殖流行病学家对人类生殖力模型感兴趣，以确定生殖功能障碍的决定因素和原因。还有人怀疑，各种环境因素对人类生育力产生了负面影响。尽管进行了广泛的努力(例如，Weinberg和Gladen(1986)，周和其他人(1996)，Scheike和Jensen(1997)，Dunson和周(1997)，Dunson和Stanford(2005)等)，但对繁殖力数据进行建模在统计学上仍然是一项具有挑战性的任务。事实上，随着对受孕能力的建模从人口学和基于人口的背景转向生殖生物学和不孕不育的治疗，新的形势强烈呼吁：1)灵活性，因为研究人员收集的信息数量不断增加；2)稳健性，因为在日常医疗实践中，对估计的影响和由此产生的重要决定的潜在粗略解释。 影响受精性的两个主要异质性来源是生物和行为。这种区别并不排除这两个因素之间潜在的相互作用。例如，女性生育窗口的长度和男性精子的寿命都是生物学因素，它们都改变了性交模式对受孕概率的影响。一些因素已经被研究和确认为受精性受损的因素，如高龄或接触有毒物质。然而，大多数生物异质性仍然没有得到解释。同样，性交模式对受精性的影响的解释部分包括与排卵有关的特定日期的性交次数和时间、宫颈粘液的质量以及当地避孕药的使用。然而，无法解释的异质性的大小可能至少与协变量的影响一样重要。 Sundaram博士和她的合作者的研究重点是解释在观察生物因素时遇到的各种测量误差，并开发性交模式和繁殖力的联合建模方法，因为假设性交模式是固定的可能是不合理的，它们都有共同的风险因素，如高龄、生育(之前生育)，并可能受到男性和女性潜在荷尔蒙水平的影响。现将部分已完成或正在完成阶段的项目列出如下：

This project is motivated by various pregnancy studies that have been conducted and are being conducted at DESPR. These include the New York State Angler Cohort Prospective Pregnancy Study, The Impact of Physiologic and Perceived Psychosocial Stress on Time to Pregnancy and the Longitudinal Investigation of Fertility and the Environment (LIFE) Study (PI, Dr G. Buck Louis of Epidemiology Branch). Fecundability (Gini, 1926) is defined as the probability of conception in a menstrual cycle for couples having regular sexual intercourse without contraception. Reproductive epidemiologists are interested in models for human fecundity to identify the determinants and causes of reproductive dysfunction. There is also suspicion that various environmental factors negatively affect the human fertility. Despite extensive efforts (ex., Weinberg and Gladen (1986), Zhou and others (1996), Scheike and Jensen (1997), Dunson and Zhou (1997), Dunson and Stanford (2005) to name a few), modeling fecundability data remains a statistically challenging task. Indeed, as modeling of fecundability stepped from demography and population-based contexts to reproductive biology and treatment of infertility, the new situation created a strong call for: 1) flexibility, because of the important and ever increasing quantity of information researchers collect; and 2) robustness, because of the potential crude interpretations of the estimated effects and the resulting important decisions in everyday medical practice. Two main sources of heterogeneity effecting fecundability are biological and behavioral. This distinction does not preclude potential interactions between these two factors. For example, both womans length of window of fertility and mans length of life of sperm, which are biological factors, modify the effect of intercourse-pattern on the probability of conception. Several elements have been studied and confirmed as factors of impaired fecundability, such as advanced age or exposure to a toxic substance. However, most of the biological heterogeneity remains unexplained. Similarly, the explained part of the effect of intercourse pattern on fecundability includes the number and timing of intercourse on particular days in relation to ovulation, the quality of cervical mucus and the use of local contraceptives. Nevertheless, the magnitude of the unexplained heterogeneity may be at least as important as the effects of the covariates. The research focus of Dr Sundaram and her collaborators are to account for various measurement errors encountered in observing biological factors and to develop joint modeling approach for intercourse pattern and fecundability as assuming the intercourse pattern to be fixed may not be reasonable and they both share common risk factors, like advanced age, parity (previous child birth) and may be influenced by underlying hormonal levels in both male and female. Some of the projects that have been completed or are in completion stage are listed below: