Study objectives: Examine age-adjusted odds and racial/ethnic differences in self-reported difficulties falling and staying asleep and early morning awakening in midlife women to determine whether difficulty sleeping increased with progression through the menopausal transition.
Design: Longitudinal analysis.
Participants: 3,045 Caucasian, African American, Chinese, Japanese, and Hispanic women, aged 42-52 years and pre- or early peri-menopausal at baseline, participating in the Study of Women's Health Across the Nation (SWAN).
Measurements and results: Self-reported number of nights of difficulty falling asleep, staying asleep, and early morning awakening during the previous 2 weeks were obtained at baseline and 7 annual assessments. Random effects logistic regression was used to model associations between each of the 3 sleep measures and the menopausal transition, defined by bleeding patterns, vasomotor symptoms (VMS), and estradiol (E2) and follicle stimulating hormone (FSH) serum levels. Adjusted odds ratios (ORs) for difficulty falling asleep and staying asleep increased through the menopausal transition, but decreased for early morning awakening from late perimenopause to postmenopause. Naturally and surgically postmenopausal women using hormones, compared with those who were not, generally had lower ORs for disturbed sleep. More frequent VMS were associated with higher ORs of each sleep difficulty. Decreasing E2 levels were associated with higher ORs of trouble falling and staying asleep, and increasing FSH levels were associated with higher ORs of trouble staying asleep. Racial/ethnic differences were found for staying asleep and early morning awakening.
Conclusions: Progression through the menopausal transition as indicated by 3 menopausal characteristics--symptoms, bleeding-defined stages, and endogenous hormone levels--is associated with self-reported sleep disturbances.