Interplay of arsenic exposure and cigarette smoking on oxidative DNA damage in healthy males

Long-term exposure to inorganic arsenic (As) and cigarette smoking has been associated with adverse health effects such as cancer, cardiovascular disease, and respiratory disease. Oxidative stress is one of the most well-known damage mechanisms for both. However, studies on the association with induced 8-hydroxy-2-deoxyguanosine (8-OHdG) in Iran are scarce, with no study on the interactive effect of As exposure and smoking in the literature. This stratified cross-sectional study aimed to assess urinary and serum 8-OHdG levels in the relation to As exposure from drinking water, smoking and their interaction effect. This study was based on 132 healthy male subjects living in villages of Hashtroud County, Iran (2021). All participants were categorized into four groups: (i) non-As exposed, never smokers (n = 33); (ii) non-As exposed, active smokers (n = 33); (iii) As exposed, never smokers (n = 33); and (iv) As exposed, active smokers (n = 33). Data on demographic and lifestyle factors were collected, and urinary and serum levels of 8-OHdG were determined by enzyme-linked immunosorbent assay (ELISA). The smoker's daily cigarette consumption and the duration of smoking were self-reported data. Participants consuming drinking water with an As concentration > 10 µg/L had significantly higher urinary total arsenic (U-tAs) concentrations (median 26.96, IQR 21.35–37.17) µg/g Cr compared to the reference group (median 19.33, IQR 17.29–23.26) µg/g Cr. There was a significant difference in the serum concentration of 8-OHdG between groups (i) and (iii), (iv) and also between groups (ii) and (iv). We did not find a significant interaction effect of As exposure and smoking on the both urinary and serum 8-OHdG levels (P > 0.05). Serum 8-OHdG (S-8OHdG) was associated with average daily intake of As (As-ADI) (β = 0.32; 95