Search

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.

Workers in swine operations are exposed to dust, bacteria, and virus, and are at increased risk of respiratory problems. Toll-like receptors (TLR) play an important role in human immune responses to respiratory hazards. Worker gender and age may significantly modify the involvement of TLR in the etiology of these respiratory outcomes. The aim of this study was to investigate whether modification effects of worker gender and age altered associations between polymorphisms in the TLR genes and lung function. This study included 374 full-time workers from large swine operations from Saskatchewan. Information on demography, lifestyle, pulmonary function,  and blood samples were obtained. Multiple linear regression and decision tree model were used in the analysis. Among females aged <45.8 years, workers with polymorphisms of rs4696480 in the TLR2 gene exhibited markedly better lung function than workers with wild-type. These associations were not observed among female workers aged ≥45.8 years and males. Among males, workers with polymorphisms of rs187084 in the TLR9 gene displayed significantly lower lung function than those with wild-type. This male-specific association was not dependent on worker age. This is the first study to report gender-specific correlations between lung function and polymorphisms of TLR genes, and modification effects of worker age on these associations, suggesting the importance of considering gender and age in genetic association studies of airway diseases due to exposure of high concentration of respiratory hazards.

Unlabelled: BACKGROUND⁄, Objectives: Knowledge of the effects of domestic endotoxin on children's lung function is limited. The association between domestic endotoxin and asthma or wheeze and lung function among school-age children (six to 18 years of age) was examined. The interaction between endotoxin and other personal and environmental characteristics and lung function was also assessed., Methods: A case-control study was conducted in and around the rural community of Humboldt, Saskatchewan, between 2005 and 2007. Parents of cases reported either doctor-diagnosed asthma or wheeze in the previous year. Controls were randomly selected from those not reporting these conditions. Data were collected by questionnaire to ascertain symptoms and conditions, while spirometry was used to measure lung function including forced vital capacity and forced expiratory volume in 1 s. Dust collected from the child's play area floor and the child's mattress was used to quantify endotoxin, and saliva was collected to quantify cotinine levels and assess tobacco smoke exposure., Results: There were 102 cases and 207 controls included in the present study. Lower forced expiratory volume in 1 s was associated with higher mattress endotoxin load among female cases (beta=-0.25, SE=0.07 [P<0.01]). There was a trend toward lower forced vital capacity, which was associated with higher play area endotoxin load among cases with high tobacco smoke exposure (beta=-0.17, SE=0.09 [P<0.10])., Conclusions: Findings indicated that high endotoxin levels present in common household areas of rural children with asthma or wheeze may also affect their lung function. These associations may be potentiated by tobacco smoke exposure and female sex.

Few studies have examined the associations between environmental characteristics and asthma severity among children in a rural setting. The authors studied these associations using a number of asthma severity indicators. They conducted a case-control study of 6- to 18-year-old children and adolescents in Humboldt, Saskatchewan, and the surrounding area. Only cases representing subjects reporting wheeze in the past 12 months or doctor-diagnosed asthma were used for the present analysis (n = 98). Data were collected by questionnaire, while vacuumed dust (mattress and play area floor) was used for the quantification of endotoxin exposure, and saliva was used for the measurement of cotinine to assess tobacco smoke exposure. Severity indicators included wheeze frequency, breathing medication use, sleep disruption from wheeze, and school absenteeism, all in the past 12 months. A majority of cases were male (62.3%). Wheezing 1 to 3 times was reported by 40.8% of cases, whereas 17.3% wheezed 4 or more times in the past 12 months. Short-acting beta agonist medications or inhaled corticosteroids alone were used by 24.5% of the cases, whereas 33.7% of the cases used multiple or additional breathing medications. Sleep disruption was reported by 28.6% of the cases, whereas 12.2% reported at least one school absence. High tobacco smoke exposure was associated with increased wheeze frequency. There was an inverse association between play area endotoxin concentration and school absenteeism, with some indication of interaction with tobacco smoke exposure. House-cleaning behaviors and changes in health behaviors resulting from the child's respiratory condition were different between those with and without report of sleep disruption due to wheeze. Several environmental variables were associated with severity indicators. However, the associations were not consistent between indicators, suggesting that other factors or changes in behavior resulting from the disease should be considered when assessing these associations.