Global DNA methylation and its association with lead exposure, B vitamin deficiency and lifestyle variables among Pb- recycling workers.

Introduction Lead (Pb) exposure affects the methylation of DNA. However, the relationship between global DNA methylation (5 methylcytosine) and Pb-exposure outcomes among occupationally exposed recycling workers needs to be ascertained. The current study aimed to evaluate the association of Pb-exposure and global DNA methylation by considering lifestyle variables and B vitamin deficiency among Pb-exposed recycling workers. Methods This cross-sectional study assessed Pb exposure, B-vitamin status, lifestyle variables, and 5-methylcytosine (5 mC) levels in 164 male workers exposed to Pb from the leadrecycling process in India, in 2022. The lead concentration in the blood sample was determined using the inductively coupled plasma emission spectrometer (ICP-OES) method. Serum levels of B vitamins and 5mC were assessed with enzyme-linked immunosorbent assay (ELISA) protocols. A pre-structured questionnaire was used to obtain information about demographic and lifestyle factors. SPSS version 23 was used for the statistical analysis of the data. Results The findings of the univariate model demonstrated that global DNA methylation was significantly decreased by experience (≥5 years), vitamin B9 deficiency, and blood lead levels (BLLs) of 30–50 and >50 μg/dL. In the stepwise multiple linear regression analysis, experience (β= -0.283; p=0.001), increased BLLs (β= -0.195; p=0.010), tobacco chewing (β= -0.184; p=0.014), and vitamin B9 deficiency (β= -0.157; p=0.037) were negatively and significantly associated with methylation of DNA. Conclusions The results indicated that the Pb exposure consequences (a range of doses and times), vitamin B9 deficiency, and chewing of tobacco products contributed to reduced methylation of DNA, which could be attributed to epigenetic deregulation and overexpression within the study population.