Poor sleep in relation to natural menopause: a population-based 14-year follow-up of midlife women.

OBJECTIVE: This study aims to estimate the prevalence and predictors of moderate/severe poor sleep in relation to the final menstrual period (FMP) in midlife women.

METHODS: Annual assessments were conducted in a population-based cohort of 255 women. All were premenopausal at cohort enrollment and reached natural menopause during the 16-year follow-up. The outcome measure was severity of poor sleep, as reported by participants in annual interviews for 16 years and as evaluated in relation to the FMP.

RESULTS: The annual prevalence of moderate/severe poor sleep largely ranged from about 28% to 35%, with no significant differences in any year relative to the FMP for the sample overall. When sleep status was stratified at premenopausal baseline, premenopausal sleep status strongly predicted poor sleep around the FMP. Women with moderate/severe poor sleep in premenopause were approximately 3.5 times more likely to have moderate/severe poor sleep around menopause than those with no poor sleep at baseline in adjusted analysis (odds ratio, 3.58; 95% CI, 2.50-5.11; P < 0.0001), whereas mild poor sleepers in premenopause were approximately 1.5 times more likely to have moderate/severe poor sleep around menopause (odds ratio, 1.57; 95% CI, 0.99-2.47; P = 0.053). There was no significant association between poor sleep and time relative to the FMP among women who had no poor sleep at premenopausal baseline. Hot flashes were significantly associated with poor sleep (odds ratio, 1.79; 95% CI, 1.44-2.21; P < 0.0001 in adjusted analysis) but had no interaction with baseline sleep severity (interaction P = 0.25), indicating that hot flashes contributed to poor sleep regardless of baseline sleep status.

CONCLUSIONS: Findings show a high prevalence of moderate/severe poor sleep in midlife women, with only a small "at-risk" subgroup having a significant increase in poor sleep in relation to the FMP. Sleep status at premenopausal baseline and concurrent hot flashes strongly and consistently predict poor sleep in the menopausal transition. Overall, poor sleep does not increase around the FMP and frequently occurs in the absence of hot flashes, indicating that sleep difficulties in the menopausal transition in generally healthy women are not simply associated with ovarian decline.