[Relationship between internal exposure levels and age and abnormal liver function in dimethylformamide exposed workers].

<b>Objective:</b> To explore the relationship between internal dimethylformamide (DMF) exposure levels and age and abnormal liver function in occupationally exposed workers, and to provide a reference for the prevention of DMF-induced toxicity. <b>Methods:</b> A total of 388 DMF exposed workers from 4 synthetic leather enterprises in Taicang City were selected by cluster sampling method from May to October 2024, and the data of occupational health examination and biological exposure indicators were collected. The relationship between N-methylcarbyl hemoglobin adduct (NMHb) and age and serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), AST/ALT and gamma-glutamyl transpeptidyase (γ-GT) was analyzed by logistic regression, interaction effect analysis, and restricted cubic spline models. <b>Results:</b> The median age of 388 workers was 45.98 years old, the median concentration of NMHb was 165.50 nmol/g Hb, and the abnormal rate of liver function was 40.7% (158/388). NMHb and age of DMF-exposed workers were the influencing factors for liver dysfunction (<i>P</i><0.05), and the multiplicative interaction between the two was not statistically significant (<i>P</i>=0.303), nor was the additive interaction statistically significant [relative excess risk due to interaction (RERI) =0.17 (95%<i>CI</i>: -2.35, 2.69), attributable proportion (AP) =0.03 (95%<i>CI</i>: -0.47, 0.54), synergy index (S) =1.04 (95%<i>CI</i>: 0.54, 2.02) ]. NMHb concentration was positively correlated with the abnormal risk of ALT, AST, AST/ALT, γ-GT and the concentration of ALT, AST, γ-GT (<i>P</i>(overall) <0.05, <i>P</i>(nonlinear)>0.05), and negatively correlated with AST/ALT (<i>P</i>(overall)=0.032, <i>P</i>(nonlinear)=0.781). Age was negatively correlated with abnormal risk of ALT, AST/ALT and ALT concentration (<i>P</i>(overall)<0.001, <i>P</i>(nonlinear)>0.05), and positively correlated with AST/ALT (<i>P</i>(overall)=0.025, <i>P</i>(nonlinear)=0.485) . <b>Conclusion:</b> There is a close relationship between NMHb and age of DMF-exposed workers and abnormal liver function. γ-GT can be used as a sensitive index, and special attention should be paid to the change of ALT index in elderly workers. Age should also be considered when AST/ALT is used as the screening indicator.