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.