Female and male sleep duration in association with the probability of conception in two representative populations of reproductive age in US and China

ObjectiveSleep duration has been found to affect some reproductive phenotypes but fecundability has been rarely researched. We aim to evaluate the association between female/male sleep duration and the probability of conception in two representative populations.MethodsThe present study uses two datasets, namely, a cross-sectional dataset of 9137 reproductive-age females in the US (National Health Interview Survey, NHIS) and a longitudinal dataset of 2687 reproductive-age females and their male mates in China (China Health and Nutrition Survey, CHNS). Logistic regression or mixed model was used to analyze the association between sleep duration and the probability of conception in the females of both populations and in CHNS males with adjustments for demographic, socioeconomic, behavioral, sleep health and reproductive factors.ResultsAn inverse association was observed between male sleep duration (≥8 h/day) and their mates' conception probability in the CHNS population (P = 0.012). Sleep of 9 h/day and ≥10 h/day in men was associated with 0.65 (0.41–1.02) fold and 0.53 (0.31–0.90) fold of conception probability when compared to 8 h/day sleep. On the other hand, a U-shaped association between female sleep duration and conception probability was observed in both populations. Each hour/day departure (longer or shorter) from 7 h/day sleep was associated with 1.26 (1.12–1.42, P < 0.001) and 1.21 (1.03–1.41, P = 0.019) fold conception probability in the NHIS and CHNS populations, respectively. An adjustment for potential confounders, including spouse characteristics did not substantially attenuate these associations.ConclusionsFemale and male sleep duration may be independent predictors of conception, suggesting there is an intervention target for reproductive health.