Phthalates exposure is associated with non-alcoholic fatty liver disease among US adults

Non-alcoholic fatty liver disease (NAFLD) has become the most common liver disease in the western countries. We aimed to ascertain the relationship of urinary phthalates concentrations with presence of NAFLD among US adults.

A cross-sectional analysis of data from National Health and Nutrition Examination Survey (NHANES) during 2003-2016 was performed. NAFLD was predicted by Hepatic Steatosis Index (HSI) and US Fatty Liver Index (US FLI), respectively. The logistic regression models were conducted to evaluate associations of urinary phthalates with NAFLD by adjustment for other covariates.

Of the 4206 participants (mean age 47.99 years old; 50.06% men), risk of suspected NAFLD was increased in those with higher concentrations of urinary phthalates. The results of multivariate models suggested that urinary phthalate metabolites MEOHP (odds ratio [OR] = 1.56, 95% confidence interval [CI] = 1.08-2.24), MEHHP (OR = 1.55, 95% CI = 1.09-2.21), MECPP (OR = 1.44, 95% CI = 1.06-1.95) and the mixtures of nine phthalates (OR = 1.58, 95%CI = 1.18-2.11) were positively related to NAFLD defined by HSI; the similar significant associations were observed for MEHHP (OR = 1.98, 95% CI = 1.32-2.97) when NAFLD was determined based upon US FLI ≥30. In subgroup analyses, the positive associations of urinary phthalates concentrations with NAFLD risk remained robust both in males and females, whereas only in individuals aged <60 years.

Phthalates exposure was independently associated with NAFLD both in males and females, regardless of being defined using HSI or US FLI.