Interactive Effect of Paraoxonase-1 Q192R Polymorphism and Smoking History on the Lung Function Decline in Grain Workers

Purpose This retrospective longitudinal study investigated the association between the Q192R polymorphism of the high-density lipoprotein–associated multifunctional antioxidant enzyme, paraoxonase-1 (PON1), and lung function decline, while taking into account smoking history. Methods The demographic, occupational, and respiratory symptom information and lung function variables were obtained from 216 male Saskatchewan grain workers. Results An interaction between the PON1 genotypes and smoking status was observed. Current smokers with the 192R allele had a lower forced expiratory volume in the first second (FEV1) and FEV1 per forced vital capacity (FVC). The annual decline rate of FEV1/FVC in current smokers was greater among 192R allele carriers than noncarriers (0.58 ± 0.05 vs. 0.35 ± 0.04 %/yr, p < 0.0001). A similar result was observed with FEV1 (40.9 ± 6.4 vs. −33.0 ± 7.0 mL/yr, p = 0.10). The annual decline rate of FVC was not influenced by the genotypes. Conclusions These results strengthened the previous findings of our cross-sectional study, suggesting that the 192R allele may be a novel genetic risk factor for airway injury among current smokers.