Tumor Necrosis Factor Alpha and Pulmonary Function in Saskatchewan Grain Handlers

Effects of tumor necrosis factor (TNF) gene polymorphisms on the association between smoking and lung function among workers in swine operations

Workers in swine operations may be at increased risk of developing respiratory problems. These respiratory conditions are more prevalent among workers who are smokers. Tumor necrosis factor (TNF) genes play an important role in human immune responses to various respiratory hazards. This study aimed to investigate whether polymorphisms in TNF genes might alter the effects of smoking on lung function among workers in swine operations. Three hundred and seventy-four full-time workers from large swine operations and 411 non-farming rural dwellers in Saskatchewan were included in this study. Information on demographic and lifestyle characteristics, pulmonary function, and blood samples were obtained. Multiple linear regression analyses were used in the statistical analysis. Three promoter polymorphisms (rs1799724, rs361525, and rs1800629) in the TNF gene were investigated. Only the interaction term between smoking status and rs1799724 was significant in the multiple regression models. Among workers with the rs1799724 polymorphism (TT+TC), current smokers exhibited significantly lower lung function than nonsmokers. These associations were not observed among workers with the wild-type (CC). These findings were not observed among non-farming rural dwellers. Data demonstrated the possible involvement of TNF gene in (1) development of adverse respiratory conditions among workers who are smokers, (2) importance of smoking cessation among workers, especially those with polymorphisms in the TNF gene, and (3) potential implications in treatment, screening, and prevention.

Association between paraoxonase-1 Q192R polymorphism and lung function among Saskatchewan grain handlers

Introduction: Paraoxonase-1 (PON1) is a high-density, lipoprotein-associated, multifunctional antioxidant enzyme that is detected in nonciliated bronchiolar epithelial cells, although its role in the lung has not yet been clarified. We therefore investigated the association between the PON1 Q192R polymorphism and lung function. Patients & Methods: A total of 216 male Saskatchewan grain handlers provided demographic, occupational and respiratory-symptom information by means of questionnaires, and thereafter underwent PON1 Q192R genotyping and lung-function testing. Results: Mean lung-function values did not differ among the Q192R genotypes. However, current smokers with the Q/Q genotype had a higher mean percent predicted forced expiratory volume in the first second (FEV1), and absolute and percent predicted FEV1 per forced vital capacity (FVC) compared with current smokers with at least one 192R allele (100.9 ± 11.2% vs 92.0 ± 15.1%, p = 0.01; 78.0 ± 5.9% vs 74.1 ± 6.8%, p = 0.03; and 96.8 ± 7.1% vs 92.1 ± 8.3%, p = 0.03; respectively). The incidence of subjects with FEV1/FVC less than 70% was significantly higher in current smokers with at least one 192R allele than in nonsmokers with the Q/Q genotype (odds ratio: 5.0; 95% confidence interval: 1.5–17.4). The protective effect of the Q/Q genotype was not found in nonsmokers. The FVC was not influenced by either PON1 genotype or smoking status. Conclusion: The results obtained from grain handlers suggest that PON1 may play some role in the protection of the airways against the toxicity of cigarette smoke, and the 192R allele may be a novel genetic risk factor for airway injury.