To investigate the association of urinary phthalate metabolites with 4 high-density lipoprotein-cholesterol(HDL-C)-related inflammatory indicators [lymphocyte/HDL-C ratio (LHR), monocyte/HDL-C ratio (MHR), neutrophil/HDL-C ratio (NHR), and platelet/HDL-C ratio (PHR)], and to explain their possible biological mechanisms.

The 4573 adult participants from the National Health and Nutrition Examination Survey (NHANES) were subjected, and then generalized linear regression (GLM), restricted cubic spline (RCS), and weighted quantile sum (WQS) regressions were performed to explore the potential associations of phthalates mono-exposures and mixed exposures, respectively, with the HDL-C-related inflammation metrics.

Nine urinary phthalate metabolites were significantly positively associated with at least 1 inflammatory marker, while 1 metabolite (MEP) showed a negative association with an inflammatory indicator (LHR). Some exposure metabolites showed a nonlinear association with outcome inflammatory indicators. WQS regression revealed varying weight contributions of individual metabolite to each inflammatory outcome. Subgroup analyses indicated differential association effects of phthalates with HDL-C-related inflammatory metrics across gender, age, and BMI populations.

There are associations between phthalate exposure and HDL-C-related inflammation indicators, but further studies are needed to reveal the underlying mechanisms.