Association of sleep duration and quality with age at natural menopause: results from NHANES 2005–2018

BACKGROUND: While sleep is closely related to menopause, existing research has primarily focused on the impact of menopause on sleep, leaving the influence of sleep patterns on the timing of menopause largely unexplored. This study aimed to investigate the associations of sleep duration and quality with age at natural menopause. METHODS: This study included women with complete data on sleep patterns and natural menopausal age from the National Health and Nutrition Examination Survey (NHANES) cycles 2005-2018. Logistic and linear regression models, progressively adjusted for demographic, lifestyle, and health-related covariates, were used to examine the relationships of sleep duration and quality with menopausal age, analyzed both as categorical (early/late menopause) and continuous variables. Restricted cubic splines were applied to assess nonlinear associations. Subgroup analyses and alternative menopausal age classifications were also performed. RESULTS: A total of 2,157 women were included. Compared with medium sleep duration (7-9 hours), short sleep duration (< 7 hours) was associated with higher odds of early menopause in the initial model (OR = 1.41, 95% CI: 1.08-1.84, p = 0.01), but this association was attenuated in the fully adjusted model. Restricted cubic spline analysis revealed a nonlinear U-shaped association between sleep duration and early menopause (p for nonlinearity = 0.04), and an inverted U-shaped association with natural menopausal age (p for nonlinearity < 0.01), both peaking around 7.5 hours. Poor sleep quality remained significantly associated with early menopause after full adjustment (OR = 1.30, 95% CI: 1.01-1.66), but not with late menopause. In subgroup analyses, short sleep duration showed a stronger association with early menopause in women with BMI ≥ 28 and those without hormone use. Interestingly, poor sleep quality was positively associated with late menopause among women with ≥ 3 live births and no history of oral contraceptive use. CONCLUSIONS: Short sleep duration and poor sleep quality may be associated with early menopause, with evidence of nonlinear relationships and subgroup heterogeneity. In certain populations, poor sleep quality may also be linked to later menopause. These findings highlight the complex role of sleep in reproductive aging, requiring prospective studies to clarify causal pathways.