Associations between estradiol levels and subjective sleep parameters in a large cohort of men and women

Introduction: Estradiol may influence sleep–wake rhythms via modulation of the circadian timing system, but evidence is limited and often based on small samples. This study examined associations between serum estradiol levels and sleep parameters in men and in pre-and postmenopausal women from the general population. Methods: This cross-sectional analysis used baseline data from the Netherlands Epidemiology of Obesity (NEO) study. Estradiol was measured in fasting serum using LC-MS/MS. Sleep quality and timing were assessed with the Pittsburgh Sleep Quality Index (PSQI). Associations were evaluated using multivariable weighted linear regression. Results: In the 4,754 participants (51% men; mean age 56 years), serum estradiol levels were not associated with sleep quality or timing. Participants in the highest 10th percentile of estradiol showed marginally better sleep quality compared with those in the middle range (difference in PSQI =-0.74; 95% CI:-1.11 to-0.36). Discussion: These findings suggest that, under physiological conditions, estradiol levels are not clearly linked to sleep quality or timing.