DNA adduct levels and DNA repair polymorphisms in traffic-exposed workers and a general population sample

Peripheral blood DNA adducts have been considered an acceptable surrogate f or target tissues and possibly predictive of cancer risk. A group of 114 wo rkers exposed to traffic pollution and a random sample of 100 residents wer e drawn from the EPIC cohort in Florence, a population recently shown to pr esent increased DNA adduct levels (Palli et of., Int J Cancer 2000;87:444-5 1). DNA bulky adducts and 3 DNA repair gene polymorphisms were analyzed in peripheral leukocytes donated at enrollment, by using P-32-postlabeling and PCR methods, respectively. Adduct levels were significantly higher for tra ffic workers among never smokers (p = 0.03) and light current smokers (p = 0.003). In both groups, urban residents tended to show higher levels than t hose living in suburban areas, and a seasonal trend emerged with adduct lev els being highest in summer and lowest in winter. Traffic workers with at l east I variant allele for XPD-Lys751 Gin polymorphism had significantly hig her levels in comparison to workers with 2 common alleles (p = 0.02). A mul tivariate analysis (after adjustment for age, season, area of residence, sm oking, XPD-Lys751 Gin genotype and antioxidant intake) showed a significant 2-fold association between occupational exposure and higher levels of addu cts (odds ratio 2.1; 95% confidence interval 1.1-4.2), in agreement with re cent pooled estimates of increased lung cancer risk for similar job titles. Our results suggest that traffic workers and the general population in Flo rence are exposed to high levels of genotoxic agents related to vehicle emi ssions. Photochemical pollution in warmer months might be responsible for t he seasonal trend of genotoxic damage in this Mediterranean urbanized area. (C) 2001 Wiley-Liss, Inc.