Study Design and Participants

SWAN is a multi-ethnic/multi-racial, community-based, cohort study of the menopausal transition. Initiated in 1996, 3,302 women were enrolled at seven sites: Boston, MA, Chicago, IL, Detroit area, MI, Los Angeles and Oakland, CA, Newark, NJ, and Pittsburgh, PA. Study design and recruitment of the SWAN cohort have been described in detail.¹³ Briefly, each site recruited white women and a racial/ethnic minority group. Eligible women were 42–52 years, premenopausal or early perimenopausal, had an intact uterus and at least one ovary, had at least one menstrual period in the previous three months, and were not pregnant/lactating or using any sex steroid hormones in the three months preceding the baseline interview. Extensive data on psychological, social and health parameters were collected at baseline and at follow-up visits scheduled at approximately 12- to 18-month intervals. Institutional review board approval was obtained at each SWAN study site and written informed consent was obtained from participants at each visit.