Quantifying the exposure-response relationship between temperature exposure and semen quality

Background: High temperature exposure impacts semen quality, but the exposure-response relationship needs further study. Objectives: Quantify the correlations and nonlinear relationships between apparent temperature (AT) exposure and semen quality parameters. Methods: A total of 5,114 individuals were enlisted as participants from a reproductive medicine center in Wenzhou, a developed coastal cities in eastern China. Multivariate linear regression models were used to quantify the correlations between AT exposure and semen quality parameters. Restricted cubic spline (RCS) and piecewise regression were employed to validate the nonlinear and threshold effects of the exposure-response relationships. Results: < 0.05). The AT range associated with optimal semen quality parameters was approximately 17.57-22.69 °C based on segmented analysis. Conclusions: Elevated exposure to apparent temperature in the 90 days prior to donation was associated with reduced semen quality. Avoiding excessive temperature exposure, particularly within a 2-week pre-ejaculation window, helps to maintain ideal semen quality.