Nurses' Health Study (NHS)

The Nurses' Health Study is an on-going prospective cohort study of women that was initiated in 1976. This specific study was part of a larger study to advance our knowledge of breast cancer etiology, expand the current knowledge of mammographic density, and clarify the relationship between mammographic density and breast cancer risk. We conducted a nested case control study of breast cancer among women who provided a blood sample. We then targeted our mammogram collection to participants that were selected as part of this nested case-control study (i.e. those who had provided a blood sample). The mammogram closest to the date of blood draw (~1989-1990) was used. We assessed mammographic breast density from digitized film images using a computer assisted thresholding method (Cumulus). The women in this study were genotyped using the Illumina Omni Express Platform. ]]>
All women that were part of a nested case control study of breast cancer (i.e., both cases and matched controls were eligible) who had a pre-diagnostic mammogram, had given blood samples and had not been previously genotyped using a GWAS platform. ]]>
The Nurses' Health Study was established in 1976 with funding from the National Institutes of Health. The primary motivation in starting the NHS was to investigate the potential long term consequences of the use of oral contraceptives, a potent drug that was being prescribed to hundreds of millions of normal women. Registered nurses were selected to be followed prospectively. Married registered nurses who were aged 30 to 55 in 1976, who lived in the 11 most populous states and whose nursing boards agreed to supply the study with their members' names and addresses were enrolled in the cohort if they responded to our baseline questionnaire. The original states were California, Connecticut, Florida, Maryland, Massachusetts, Michigan, New Jersey, New York, Ohio, Pennsylvania and Texas. Approximately 122,000 nurses out of the 170,000 mailed responded. Every two years cohort members receive a follow-up questionnaire with questions about diseases and health-related topics including smoking, hormone use and menopausal status. Similarly, to identify potential biomarkers, such as hormone levels and genetic markers, 33,000 blood samples were collected in 1989-90 followed by second samples from 18,700 of these participants in 2000-01. These samples are stored and used in case/control analyses. Additionally, we collected film screening mammograms from a subset of women to measure their mammographic density. ]]>