The association between circadian syndrome and female infertility: results from the National Health and Nutrition Examination Survey (NHANES)

Circadian syndrome has been increasingly recognized as a marker of systemic circadian disruption. This study examined the association between circadian syndrome and lifetime infertility among U.S. women using nationally representative NHANES data. We analyzed 2,512 women aged 2045 years from NHANES 20132018. Circadian syndrome was defined as the presence of ≥4 of 7 components: central obesity, elevated glucose, elevated triglycerides, reduced HDL-C, elevated blood pressure, short sleep, and depression. Survey-weighted logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Subgroup and trend analyses were also performed, and restricted cubic spline analysis was used to assess potential nonlinear associations. Women with circadian syndrome had higher odds of infertility (unadjusted OR 1.87; 95% CI 1.442.42; adjusted OR 1.62; 95% CI 1.222.13). Infertility risk increased with the number of components (p-trend = 0.004); women with ≥=6 components showed the strongest association (adjusted OR 1.98; 95% CI 1.292.98). Central obesity, depression, and short sleep were independently associated with infertility. Restricted cubic spline analysis showed no significant nonlinear association between sleep duration and infertility (P for nonlinearity = 0.485). Circadian syndrome is significantly associated with higher odds of infertility in U.S. women.