Di-2-ethylhexyl phthalate (DEHP) exposure increase female infertility

This study explores the relationship between Di-2-ethylhexyl phthalate (DEHP) exposure and female infertility. The analysis included 998 female participants aged between 18 and 44 years. We analyzed data from the National Health and Nutrition Examination Survey (2013–2018) using multiple logistic regression and generalized linear models to assess the impact of DEHP on infertility. Additionally, we employed curve fitting and two-piecewise linear regression models to investigate potential nonlinear correlations, conducting subgroup analyses based on age, BMI, alcohol consumption, smoking status, hypertension, and diabetes. Our results, after adjusting for confounders, revealed a positive association between DEHP exposure and infertility. This association was significant whether DEHP was treated as a continuous variable (odds ratio OR = 1.28, 95 % confidence interval CI: 1.08–1.52, P = 0.0072) or as a categorical variable (P for trend = 0.0038). A non-linear relationship was identified, with an inflection point at − 3.35 (∑DEHP = 0.0981 × 10⁻⁹ mol/mg creatinine). Effect sizes were 1.55 (1.01–2.36) on the left side of the inflection point and 0.73 (0.43–1.23) on the right side. Subgroup analysis indicated that the correlation was consistent across stratified variables. In conclusion, our findings suggest a non-linear association between DEHP exposure and female infertility, with a positive correlation within a specific dose range, but no further increase in risk beyond a certain threshold.