Fig. 2

Exposure-response curves and 95% confidence intervals (CIs) for the relationship between environment temperature and sperm quality (sperm concentration, percentage of normal sperm morphology, and progressive motility) at four exposure windows (lag 0–9, lag 10–14, lag 15–69, lag 70–90 and lag 0–90 days) estimated using a generalized linear model by including a natural cubic spline function (df = 3) of temperature exposure adjusted for body mass index (BMI), education level, smoking status, season of semen sample, days abstaining, and relative humidity. The vertical black lines along the horizontal axes give the distribution of ambient temperature of the study population