XRCC1 Arg194Trp polymorphism and risk of chronic obstructive pulmonary disease

The DNA damage, caused by cigarette smoking, can cause airway cell apoptosis and death, which may be associated with the development of chronic obstructive pulmonary disease (COPD). However, just 20%-30% smokers develop COPD, which suggests that different degrees of DNA repair cause different outcomes in smokers. X-ray repair cross-complementing group 1 (XRCC1), a base excision repair protein, has multiple roles in repairing ROS-mediated, basal DNA damage and single-strand DNA breaks. The present study investigated the association between polymorphism in XRCC1 (Arg399Gln) and susceptibility of COPD. A total of 201 COPD cases and 309 controls were recruited and frequency-matched on age and sex. XRCC1 genotype was determined by PCR-restriction fragment length polymorphism analysis. Overall, compared with those with the XRCC1 Arg/Arg genotype, the risk for COPD had no significant difference among individuals with Trp/Trp genotype. However, after stratifying by smoking status, in former smokers, compared with those with the XRCC1 Arg/Arg genotype, the risk for COPD was significantly reduced among individuals with Trp/Trp genotype (adjusted OR=0.22, 95% CI 0.06-0.85, P=0.028); after stratifying by smoking exposure, in light smokers, compared with those with the XRCC1 Arg/Arg genotype, the risk for COPD was significantly reduced among individuals with Arg/Trp genotype and Trp/Trp genotype (adjusted OR=0.39, 95% CI 0.16-0.94, P=0.036; 0.24, 95% CI 0.07-0.79, P=0.019, respectively). In conclusion, XRCC1 Arg194Trp genotype is associated with a reduced risk of developing COPD among former and light smokers.