The sixth vital sign: what reproduction tells us about overall health. Proceedings from a NICHD/CDC workshop.

STUDY QUESTION: Does the fertility status of an individual act as a biomarker for their future health? SUMMARY ANSWER: Data support an association between reproductive health and overall health for men and women. WHAT IS ALREADY KNOWN: Various chronic conditions, such as diabetes, obesity and cancer, can compromise fertility, but there are limited data for the converse situation, in which fertility status can influence or act as a marker for future health. Data reveal an association between infertility and incident cardiovascular disease and cancer in both men and women. STUDY DESIGN SIZE AND DURATION: A National Institute of Child Health and Human Development-Centers for Disease Control and Prevention workshop in April 2016 was convened that brought together experts in both somatic diseases and conditions, and reproductive health. Goals of the workshop included obtaining information about the current state of the science linking fertility status and overall health, identifying potential gaps and barriers limiting progress in the field, and outlining the highest priorities to move the field forward. PARTICIPANTS/MATERIALS SETTING AND METHODS: Approximately 40 experts participated in the workshop. MAIN RESULTS AND THE ROLE OF CHANCE: While the etiology remains uncertain for infertility, there is evidence for an association between male and female infertility and later health. The current body of evidence suggests four main categories for considering biological explanations: genetic factors, hormonal factors, in utero factors, and lifestyle/health factors. These categories would be key to include in future studies to develop a comprehensive and possibly standardized look at fertility status and overall health. Several themes emerged from the group discussion including strategies for maximizing use of existing resources and databases, the need for additional epidemiologic studies and public health surveillance, development of strategies to frame research so results could ultimately influence clinical practice, and the identification of short and long-term goals and the best means to achieve them. LIMITATIONS REASONS FOR CAUTION: Further research may not indicate an association between fertility status and overall health. WIDER IMPLICATIONS OF THE
FINDINGS: Currently medical care is compartmentalized. Reproductive medicine physicians treat patients for a short period of time before they transition to others for future care. Going forward, it is critical to take an interdisciplinary patient care approach that would involve experts in a broad range of medical specialties in order to more fully understand the complex interrelationships between fertility and overall health. If infertility is confirmed as an early marker of chronic disease then screening practices could be adjusted, as they are for patients with a family history of malignancy. STUDY FUNDING/COMPETING INTERESTS: Funding for the workshop was provided by the Fertility and Infertility Branch, National Institute of Child Health and Human Development, National Institutes of Health and the Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control. There are no conflicts of interest to declare. The findings and conclusions in this article are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention or the National Institutes of Health. TRIAL REGISTRATION NUMBER: Not applicable.