Association Between Sleep Quality and Semen Parameters and Reproductive Hormones: A Cross-Sectional Study in Zhejiang, China

Background: The effects of sleep duration on semen quality have been documented in many epidemiological studies. However, the association between sleep quality and semen parameters and reproductive hormones is still unclear. Patients Enrollment and Methods: We conducted a cross-sectional study among 970 outpatients from the Reproductive Medicine Center in Zhejiang, China between October 2017 and July 2019. All participants delivered a semen sample, underwent a physical examination, and answered a questionnaire to provide the following information: demographics, life habits, and sleep habits. Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI). We first divided the patients into two groups according to sleep quality (good sleep: PQSI > 5 and poor sleep: PSQI >= 5). Then, we analyzed routine sperm parameters (semen volume, sperm total motility, progressive motility, sperm concentration, total sperm number, and normal sperm morphology) and reproductive hormones (folliclestimulating hormone, luteinizing hormone, estrogen, testosterone, and prolactin) of each group. Finally, we used multivariate linear regression analysis and Spearman correlation coefficients to examine the relationship between sleep quality (discrete variable or dichotomous variable) and sperm parameters, reproductive hormones. Results: A negative correlation was found between the general PSQI scores and several semen parameters: total motility (r= -0.187979, p< 0.001), progressive motility (r= -0.192902, p< 0.001), concentration (r= -0.167063, p< 0.001), total sperm number (r= -0.160008, p< 0.001), and normal sperm morphology (r= -0.124511, p< 0.001). However, there was no significant correlation between the semen volume, all reproductive hormones and the general PSQI scores. After adjusting for confounders, men with poor sleep had lower total motility (beta= -9.287; 95% CI, -12.050, -6.523), progressive motility (beta= -8.853; 95% CI, -11.526, -6.180), concentration (log scale, beta= -0.131; 95% CI, -0.181, -0.082), total sperm number (log scale, beta= -0.137; 95% CI, -0.189, -0.084), and normal sperm morphology (beta= -1.195; 95% CI, -1.844, -0.547), but semen volume and all reproductive hormones were not markedly altered. Conclusion: Poor sleep quality might be related to impaired semen quality, but we found no evidence that poor sleep quality affects reproductive hormones.