Interactions between single nucleotide polymorphism of SERPINA1 gene and smoking in association with COPD: a case–control study
BACKGROUND
SERPINA1 gene has been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD), while smoking is a known risk factor for COPD. Little is known on the effect of SERPINA1 gene and its interaction with smoking in the Chinese population. In this study, the effect of SERPINA1 gene polymorphisms on COPD risk and its interaction with smoking status has been investigated.


METHOD
A total of 120 COPD patients and 481 healthy controls were recruited at The Armed Police Corps Hospital. Data on demographic variables, smoking status, history of occupational dust exposure, and allergies were collected. Genotyping for single nucleotide polymorphism's (SNP) rs1243160, rs2854254, and rs8004738 was performed in all participants.


RESULTS
SNP rs8004738 genotype was associated with a significantly higher risk for COPD (odds ratio (OR) =1.835, 95% confidence interval (CI): 1.002-3.360), whereas SNPs rs1243160 and rs2854254 did not exhibit such an association. Smoking habit also significantly increased the risk for COPD (OR =2.306, 95% CI: 1.537-3.459). On stepwise logistic regression analysis, advanced age, smoking, and SNP rs8004738 variant were associated with increased risk for COPD, while female gender and higher educational status decreased the risk. On additive interaction analysis, a significant interactive effect of SNP rs8004738 and smoking was observed in this population (relative excess risk due to interaction =0.478; attributable proportion due to interaction (AP) =0.123; S=1.197).


CONCLUSION
SNP rs8004738 of SERPINA1 gene significantly interacted with smoking status and was associated with a higher risk for COPD in the Chinese population.