Does healthy lifestyle attenuate the associations of phthalates with depression? A cross-sectional study

Phthalates have raised concerns on health outcomes including depression, due to its ubiquity. Knowledge is lacking on the role of modifiable lifestyle in attenuating phthalates’ adverse effects. We aimed to evaluate the interaction effects of lifestyle with urinary phthalate metabolites (UPMs) on depression. A total of 3588 participants aged ≥ 20 from the National Health and Nutrition Examination Survey 2011–2018 were involved. We used multivariate logistic regression models and Bayesian Kernel Machine Regression models to evaluate the associations of UPMs (individual or mixture) and lifestyle with depression. Positive associations of individual UPMs and its mixture with depression were observed in total population and participants maintaining an unfavorable lifestyle. No such association was found in participants with a healthy lifestyle. Interactions between lifestyle category with MECPP (P for interaction = 0.028), and ΣDEHP (P for interaction = 0.087) on depression were observed. Additionally, smoking, alcohol consumption and physical activity in healthy levels showed the greatest effect against depression among the common lifestyle combinations. In conclusion, positive associations of UPMs with depression risk, and interaction effects of lifestyle and UPMs on depression were observed. Our findings indicate that healthy lifestyle might weaken the adverse effects of phthalate exposure on depression risk.