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Objectives: To review the contribution of the Nurses' Health Study (NHS) and NHS II to genomics, epigenetics, and metabolomics research., Methods: We performed a narrative review of the publications of the NHS and NHS II between 1990 and 2016 based on biospecimens, including blood and tumor tissue, collected from participants., Results: The NHS has contributed to the discovery of genetic loci influencing more than 45 complex human phenotypes, including cancers, diabetes, cardiovascular disease, reproductive characteristics, and anthropometric traits. The combination of genomewide genotype data with extensive exposure and lifestyle data has enabled the evaluation of gene-environment interactions. Furthermore, data suggest that longer telomere length increases risk of cancers not related to smoking, and that modifiable factors (e.g., diet) may have an impact on telomere length. "Omics" research in the NHS continues to expand, with epigenetics and metabolomics becoming greater areas of focus., Conclusions: The combination of prospective biomarker data and broad exposure information has enabled the NHS to participate in a variety of "omics" research, contributing to understanding of the epidemiology and biology of multiple complex diseases.

Purpose: Although previous studies have implicated a variety of hormone-related risk factors in the etiology of male breast cancers, no previous studies have examined the effects of endogenous hormones., Patients and Methods: Within the Male Breast Cancer Pooling Project, an international consortium comprising 21 case-control and cohort investigations, a subset of seven prospective cohort studies were able to contribute prediagnostic serum or plasma samples for hormone quantitation. Using a nested case-control design, multivariable unconditional logistic regression analyses estimated odds ratios and 95% CIs for associations between male breast cancer risk and 11 individual estrogens and androgens, as well as selected ratios of these analytes., Results: Data from 101 cases and 217 matched controls were analyzed. After adjustment for age and date of blood draw, race, and body mass index, androgens were found to be largely unrelated to risk, but circulating estradiol levels showed a significant association. Men in the highest quartile had an odds ratio of 2.47 (95% CI, 1.10 to 5.58) compared with those in the lowest quartile (trend P = .06). Assessment of estradiol as a ratio to various individual androgens or sum of androgens showed no further enhancement of risk. These relations were not significantly modified by either age or body mass index, although estradiol was slightly more strongly related to breast cancers occurring among younger (age < 67 years) than older men., Conclusion: Our results support the notion of an important role for estradiol in the etiology of male breast cancers, similar to female breast cancers., (© 2015 by American Society of Clinical Oncology.)