Combined effect of grain farming and smoking on lung function and the prevalence of chronic bronchitis

Prevalence and Characteristics of Chronic Obstructive Pulmonary Disease in Dairy Farmers

Objective: To assess the prevalence and characteristics of chronic obstructive pulmonary disease (COPD) in dairy farmers, and evaluate the role of job exposure and smoking as predictors for respiratory health impairment. Methods: A cross-sectional study was performed, including 83 dairy farmers (mean age: 52.6±8.7 years; mean exposure duration: 23.7±7.6 years) and 80 office workers as a control group (mean age: 52.7±8.2 years) matched for age, smoking habits, and socioeconomic status. Methods for evaluation of study participants included a questionnaire on respiratory symptoms in the last 12 months, baseline spirometry and bronchodilator reversibility testing, and diagnostic criteria for COPD. Results: The mean post-bronchodilator values of spirometric parameters are significantly lower in subjects among EG with negative bronchodilator test compared to those in CG, while the mean post-bronchodilator values of spirometric parameters are lower in dairy farmers with negative BD tests exposed more than 20 years compared to those with exposure less than 20 years, being statistically significant for FEV1/FVC%, MEF25, MEF50 and MEF75. The COPD prevalence is non-significantly higher in dairy farmers compared to controls, and is significantly associated with age over 40 years in dairy farmers (P=0.035). The risk for COPD development in dairy farmers is about 36 fold higher in subjects exposed more than 20 years (OR = 36.00 (1.21-37.77) CI 95%) compared to those with exposure duration less than 20 years, and is about 6 fold higher in dairy farmers who are current smokers (OR = 6.12 (0.95-37.77) CI 95%). COPD is significantly associated with smoking duration among smokers in both groups, while combined effect of smoking, smoking duration, and number of cigarettes smoked daily has a significant impact on COPD development in dairy farmers. According to the GOLD classification, depending on the degree of airflow limitation, mild and moderate types of COPD are detected in dairy farmers, and only mild type in controls, showing no significant difference between the two groups. Conclusion: The study findings recognized the role of farming exposure, and smoking as well, as predictors for respiratory health impairment, and furthermore confirmed their potential to be a predictive factor in the COPD development. These facts should be helpful in detection of critical points for action, indicate the need of adverse occupational exposures reduction through adequate preventive measures and regular health examinations, implementation of relevant engineering controls, smoking cessation programs, and complete and efficient respiratory health assessment.

Prevalence and Risk Factors of ACO (Asthma-COPD Overlap) in Aboriginal People

Background and Objective

Aboriginal peoples are at a higher risk of many chronic respiratory diseases compared to the general Canadian population. Patients with asthma-COPD overlap (ACO), a disease newly described in 2015, are associated with frequent exacerbations, rapid decline in lung function, poor quality of life, high mortality, and disproportionate utilization of health-care resources than patients with asthma and COPD alone. The objective was to investigate the prevalence and risk factors of ACO in Aboriginal peoples.

Methods

Data from the 2012 Aboriginal Peoples Survey (APS) were used for this study. The ACO definition was based on the respondent giving positive responses to both of the following questions "Do you/Does (name) have Asthma diagnosed by a health professional?" and "Do you/Does (name) have chronic bronchitis, emphysema or chronic pulmonary obstructive disease or COPD diagnosed by a health professional?" Results. Aboriginal peoples older than 45 years, women, widowed, separated, or divorced, having a total personal income below $20,000 were associated with a significant risk of ACO. Residing in Ontario, being a daily smoker, living in a rented dwelling, dwelling in need of major repairs, having diabetes, and working more than 40 hrs a week were also significantly associated with increased risk of ACO.

Conclusion

The results from this study will provide information to aid the development of prevention and intervention strategies for Aboriginal communities.

Chronic Respiratory Symptoms and Lung Function in Agricultural Workers - Influence of Exposure Duration and Smoking

INTRODUCTION

Job exposure in agricultural workers often leads to respiratory impairment.

AIM

To assess the influence of exposure duration and smoking on chronic respiratory symptoms and ventilatory capacity in agricultural workers.

METHODS

A cross-sectional study covered 75 agricultural workers, compared with an equal number of office workers matched by age, exposure duration and smoking status. Standardized questionnaire was used to obtain data on chronic respiratory symptoms, job and smoking history. Lung functional testing was performed by spirometry.

RESULTS

The prevalence of respiratory symptoms was higher in agricultural workers, with significant difference for cough (P = 0.034), and dyspnea (P = 0.028). Chronic respiratory symptoms among agricultural workers were significantly associated with duration of exposure (P < 0.05) and daily smoking (P < 0.01), as well as with daily smoking in controls (P < 0.01). The average values of spirometric parameters in exposed workers were significantly different for MEF50 (P = 0.002), MEF75 (P = 0.000), and MEF25-75 (P = 0.049). Obstructive changes in small airways in exposed workers were strongly related to exposure duration (P < 0.05) and smoking (P < 0.01). Agricultural workers with job exposure more than 15 years had more expressed adverse respiratory symptoms and lung function decline.

CONCLUSION

The results confirmed the influence of agricultural exposure and daily smoking on chronic respiratory symptoms and airflow limitation, primarily targeting the small airways.

Chronic Respiratory Symptoms and Lung Function in a Sample of Agricultural Workers in Skopje Region

OBJECTIVE: To assess the effect of job exposure and its duration on chronic respiratory symptoms and ventilatory capacity among agricultural workers.METHODS: We performed a cross-sectional study including 120 agricultural workers aged 36 to 53 years, compared to an equal number of office workers matched by age, duration of workplace exposure and smoking status. A questionnaire was used to record the chronic respiratory symptoms, detailed job history, specific job activities and tasks performed, and smoking history. Evaluation of examined subjects also included functional lung testing by spirometry.RESULTS: We found non-significantly higher prevalence of respiratory symptoms in the last 12 months in agricultural workers with significant difference for cough (P = 0.044), and wheezing (P = 0.031). Mean values of all spirometric parameters were lower in agricultural workers, being significantly different for MEF50 (P = 0.001) and MEF75 (P = 0.000). Adverse respiratory effects and lung function deterioration were more expressed in agricultural workers with duration of job exposure more than 20 years than in those exposed less than 20 years.CONCLUSION: Our data suggest that workplace exposure in agricultural workers may lead to respiratory impairment which is close related to its duration.

The determinants of chronic bronchitis in Aboriginal children and youth

BACKGROUND

There is limited knowledge concerning chronic bronchitis (CB) in Canadian Aboriginal peoples.

OBJECTIVE

To determine the prevalence (crude and adjusted) of CB and its associated risk factors in Canadian Aboriginal children and youth six to 14 years of age.

METHODS

Data from the cross-sectional Aboriginal Peoples Survey were analyzed in the present study. Logistic regression analysis was used to determine risk factors influencing the prevalence of CB among Aboriginal children and youth. The balanced repeated replication method was used to compute standard errors of regression coefficients to account for clustering inherent in the study design. The outcome of interest was based on the question: "Have you been told by a doctor, nurse or other health professional that you have chronic bronchitis?" Demographics, environment and population characteristics (predisposing and enabling resources) were tested for an association with CB.

RESULTS

The prevalence of CB was 3.1% for boys and 2.8% for girls. Other significant risk factors of CB were age (OR 1.38 [95% CI 1.24 to 1.52] for 12 to 14 year olds versus six to eight year olds), income (OR 2.28 [95% CI 2.02 to 2.59] for income category <$25,000/year versus ≥$85,000/year), allergies (OR 1.96 [95% CI 1.78 to 2.16] for having allergies versus no allergies), asthma (OR 7.61 [ 95% CI 6.91 to 8.37] for having asthma versus no asthma) and location of residence (rural/urban and geographical location). A significant two-way interaction between sex and body mass index indicated that the relationship between the prevalence of CB and body mass index was modified by sex.

DISCUSSION

The prevalence of CB was related to well-known risk factors among adults, including older age and lower annual income.

Pulmonary function reductions among potentially susceptible subgroups of agricultural workers in Colorado and Nebraska

OBJECTIVE

Organic dust inhalation has been associated with adverse respiratory responses among agricultural workers. We evaluated factors that may confer increased susceptibility to these health effects.

METHODS

We quantified personal work shift exposures to inhalable dust, endotoxin, and its 3-hydroxy fatty acid constituents, and evaluated changes in pulmonary function among 137 grain elevator, cattle feedlot, dairy, and corn farm workers.

RESULTS

Increased dust exposure was associated with work shift reductions in lung function. Although interpretation is limited because of small samples, a suggestion of stronger exposure-response relationships was observed among smokers, as well as workers reporting pesticide/herbicide application, asthma, or allergies, and those with genetic polymorphisms (TLR4) (Pinteraction ≤ 0.05).

CONCLUSIONS

A better understanding of factors leading to increased susceptibility of adverse respiratory outcomes is needed to optimize exposure reduction strategies and develop more comprehensive wellness programs.

Association between pulmonary dysfunction as a result of occupational exposures and risk of developing cancer

BACKGROUND

Cohen's hypothesis states that pulmonary dysfunction is the underlying unifying factor that leads to numerous health risks of inhaled toxicants.

OBJECTIVE

To test the idea postulated by Cohen.

METHODS

We compiled a retrospective cohort (n = 8024) composed of participants in eight population-based research and occupational studies conducted between 1977 and 1989. Smoking history, occupational exposures, health indicators, and demographic information were obtained by questionnaire. Pulmonary function was assessed by spirometry.

RESULTS

Cox proportional hazards models were utilized to test the Cohen's hypothesis. Risk of developing cancer increased (hazard ratio, 1.31; 95% confidence interval, 1.02 to 1.67) if a subject had an obstructive pulmonary disease at baseline.

CONCLUSION

Impaired lung function caused by environmental and occupational exposures is one of the risk factors for the incidence of cancer.

Effect of particle size on respiratory protection provided by two types of N95 respirators used in agricultural settings

This study compared size-selective workplace protection factors (WPFs) of an N95 elastomeric respirator (ER) and an N95 filtering facepiece respirator (FFR) in agricultural environments. Twenty-five healthy farm workers ranging in age from 20 to 30 years voluntarily participated in this study. Altogether, eight farms were included representing three different types: two horse farms, three pig barns, and three grain handling sites. Subjects wore the ER and FFR while performing their daily activities, such as spreading hay, feeding livestock, and shoveling. Aerosol concentrations in an optical particle size range of 0.7-10 μm were determined simultaneously inside and outside the respirator during the first and last 15 min of a 60-min experiment. For every subject, size-selective WPFs were calculated in 1-min intervals and averaged over 30 min. For the ER, geometric mean WPFs were 172, 321, 1013, 2097, and 2784 for particle diameters of 0.7-1.0, 1.0-2.0, 2.0-3.0, 3.0-5.0, and 5.0-10.0 μm, respectively. Corresponding values for the FFR were 67, 124, 312, 909, and 2089. The 5th percentiles for the ER and FFR were higher than the assigned protection factor of 10 and varied from 28 to 250 and from 16 to 223, respectively. Results show that the N95 ER and FFR tested in the study provided an expected level of protection for workers on agricultural farms against particles ranging from 0.7 to 10 μm. WPFs for the ER were higher than the FFR for all particle size ranges. WPFs for both respirator types increased with increasing particle size.

Changing prevalence of obesity in a rural community between 1977 and 2003: a multiple cross-sectional study

OBJECTIVE

To determine the changes in the prevalence of obesity in a rural community between 1977 and 2003.

STUDY DESIGN

A multiple cross-sectional study.

METHODS

The analysis was based on data from four cross-sectional surveys of adults aged 25-59 years, conducted in the town of Humboldt, Saskatchewan in 1977, 1983, 1993 and 2003. People with a body mass index (BMI) > or =30 kg/m(2) were considered to be obese.

RESULTS

Average body weight increased by 8 kg for both men and women during the study period. The increase in BMI was greater in adults aged 25-39 years compared with older age groups. The prevalence of obesity increased from 24% in 1977 to 38% in 2003 for men, and from 16% to 32% for women. The change was more pronounced from 1993 to 2003 than from 1977 to 1993, especially among younger adults. Standardized to the 2003 study population by sex, age and smoking status, the prevalence of obesity was 16.8% in 1977, 22.7% in 1983, 24.7% in 1993 and 34.5% in 2003, and was much higher than the Canadian national average (16% in 2003).

CONCLUSION

There was a dramatic increase in the prevalence of obesity in rural adults, and this was greater in younger adults. Changes in cigarette smoking did not explain the increase. There is an urgent need to identify and implement effective interventions to slow if not reverse the trend, particularly in rural populations.

Pesticide use and chronic bronchitis among farmers in the Agricultural Health Study

BACKGROUND

Farmers have increased risk for chronic bronchitis. Few investigators have considered pesticides.

METHODS

We evaluated pesticides as risk factors for chronic bronchitis using the Agricultural Health Study enrollment data on lifetime pesticide use and history of doctor-diagnosed chronic bronchitis from 20,908 private pesticide applicators, primarily farmers.

RESULTS

A total of 654 farmers (3%) reported chronic bronchitis diagnosed after age 19. After adjustment for correlated pesticides as well as confounders, 11 pesticides were significantly associated with chronic bronchitis. Heptachlor use had the highest odds ratio (OR=1.50, 95% Confidence Interval (CI)=1.19, 1.89). Increased prevalence for chronic bronchitis was also seen for individuals who had a history of a high pesticide exposure event (OR=1.85, 95% CI=1.51, 2.25) and for those who also applied pesticides in off-farm jobs (OR=1.40, 95% CI=1.04, 1.88). Co-morbid asthma and current farm activities did not explain these results.

CONCLUSIONS

These results provide preliminary evidence that pesticide use may increase chronic bronchitis prevalence.

Infrequent milk consumption plus being overweight may have great risk for asthma in girls

BACKGROUND

Inadequate milk consumption and being overweight are each associated with asthma symptoms in children. Milk consumption has been inversely related to childhood overweight. Thus, being overweight may be a pathway or a confounder in milk-asthma relationship. A combination of both factors may be associated with greater risk of asthma than one factor alone.

METHODS

This study included 246 children with allergist-diagnosed asthma and 477 nonasthmatic controls at the age of 8-10 years. Information on milk consumption during the last 12 months was obtained from questionnaires. Being overweight was defined as body mass index > or =85th percentile. Being overweight as a possible pathway or confounder was formally tested. The odds ratio (OR) for combined infrequent milk consumption and being overweight in asthmatic vs nonasthmatic children was determined in multivariate logistic regression analyses.

RESULTS

There was a significant interaction between milk consumption and sex of the child in relation to asthma. Asthma was significantly associated with infrequent milk consumption in girls (crude OR 2.11, 95% CI 1.05-4.24) but not in boys. The asthma-milk relation in girls was neither mediated by being overweight (p(mediation tests) = 0.27) nor was the relationship confounded by being overweight (a 9% change in coefficient). Asthmatic girls had 3.6 times increased odds of having combination of infrequent milk consumption and being overweight than nonasthmatic girls (adjusted OR 3.64, 95% CI 1.18-11.24). Asthma was not associated with either factor or with absence of the other in girls.

CONCLUSION

Infrequent milk consumption plus being overweight may have great risk for asthma in girls.

Chronic bronchitis among nonsmoking farm women in the agricultural health study

OBJECTIVE

The purpose of this study was to examine agricultural risk factors for chronic bronchitis among nonsmoking farm women.

METHODS

We used self-reported enrollment data from the 21,541 nonsmoking women in the Agricultural Health Study to evaluate occupational risk factors for prevalent chronic bronchitis among farm women. Odds ratios (ORs) for chronic bronchitis for occupational exposures were adjusted for age, state, and related agricultural exposures.

RESULTS

Applying manure and driving combines were independently associated with chronic bronchitis. Off-farm job exposures associated with chronic bronchitis were organic dusts, asbestos, gasoline, and solvents. Five pesticides were associated with chronic bronchitis after multivariate adjustment and sensitivity analyses: dichlorvos (OR=1.63, 95% CI=1.01, 2.61), DDT (OR=1.67, 95% CI=1.13, 2.47), cyanazine (OR=1.88, 95% CI=1.00, 3.54), paraquat (OR=1.91, 95% CI=1.02, 3.55), and methyl bromide (OR=1.82, 95% CI=1.02, 3.24).

CONCLUSION

Pesticides as well as grain and dust exposures were associated with chronic bronchitis among nonsmoking farm women.

Respiratory symptoms and farming practices in farmers associated with an acute febrile illness after organic dust exposure

STUDY OBJECTIVE

To conduct a preliminary study of occupational respiratory complaints in farmers who have experienced organic dust toxic syndrome (ODTS) symptoms.

DESIGN

Cross-sectional.

SETTING

An agricultural trade show.

INTERVENTION

None.

MEASUREMENT AND RESULTS

Two hundred ninety-seven people (204 men, 93 women) completed a questionnaire about agricultural practices, respiratory health (including history of febrile episodes while handling grain), and use of respirators. Spirometry was also performed. ODTS symptoms were described by 107 of the people (36%). A strong significant association was found between ODTS and cough or chest tightness after handling grain (odds ratio [OR], 7.5; 95% confidence ratio [CI], 4.2 to 13.5). People who experienced cough or chest tightness after handling grain were more likely to report handling grain sorghum than people who had not experienced cough or chest tightening after handling grain (OR, 2.1; 95% CI, 1.3 to 3.5). The strong association seen between ODTS and frequent use of a respirator while working in grain bins (OR, 3.9; 95% CI, 1.6 to 9.4) may indicate that farmers began using respirators after respiratory symptoms developed.

CONCLUSIONS

Having a history consistent with ODTS exposure was very common in the farmers surveyed. Farmers who had a history consistent with ODTS were more likely to report cough or chest tightness with handling grain. Exposure to grain sorghum was more likely to be associated with respiratory symptoms than was exposure to other types of grain. There is a need for additional studies to further examine the relationship between ODTS and respiratory symptoms with grain dust exposure in farmers.

Respiratory and immunological findings in brewery workers

BACKGROUND

Occupational exposure of brewery workers to organic dusts such as hops, barley, and brewery yeast has the potential to change respiratory function and immunological status.

METHODS

Ninety-seven male workers employed in a brewery plant were studied. The mean age of the workers in this plant was 40 years, the mean duration of their employment was 16 years. In addition, a group of 76 unexposed workers was studied as a control. Respiratory symptoms were recorded. Lung function was measured by recording maximum expiratory flow-volume (MEFV) curves. Immunological testing was performed on all brewery workers and some control volunteers using skin prick testing with hops, barley, and yeast antigens as well as other nonoccupational allergens, and by determining total serum IgE levels.

RESULTS

There was a significantly higher prevalence of most of the chronic respiratory symptoms in brewery workers compared to controls (P < 0.01). Occupational asthma, however, was recorded in only 2 (2.1%) of the brewery workers. Logistic regression analysis showed that smoking was the major studied factor responsible for the high prevalence of chronic respiratory symptoms in workers. A large number of brewery workers complained of acute symptoms that developed during the work shift. Lung function tests were decreased compared to predicted. Multivariate analysis of these respiratory function parameters suggested the importance of workplace exposure in explaining lung function abnormalities. Significantly higher prevalences of positive skin prick tests were recorded in 37 brewery workers for molds, hops, and barley than in controls. Increased serum levels of total IgE were documented in 34/97 (45.1%) brewery workers and in 1/76 (2.7%) of the control workers (P < 0.01). However, workers with positive skin prick tests had prevalences of chronic respiratory symptoms and lung function changes similar to those of workers with negative skin prick tests.

CONCLUSION

Our data suggest that both smoking and dust exposure in the brewery industry may be responsible for the development of respiratory impairment and immunological reactions.

Segregation analysis of two lung function indices in a random sample of young families: the Humboldt Family Study

The Humboldt Family Study was conducted in the town of Humboldt, Saskatchewan, in 1993. Familial correlations and segregation analyses of lung function were carried out in 799 individuals in 214 nuclear families that included 214 fathers, 214 mothers, and 371 children. Forced expiratory volume in 1 second (FEV1) and maximal mid-expiratory flow rate (MMFR) were first regressed on age, height, weight, and their quadratic and cubic terms as well as on smoking status in four groups separately (mothers, fathers, daughters, and sons), with terms significant at the 0.10 level being retained. Residual phenotypes were standardized within the four groups. Class D regressive models were used to perform familial correlations and segregation analyses. For both FEV1 and MMFR, father-mother correlations were not significantly different from zero, and mother-offspring, father-offspring, and sibling-sibling correlations showed no statistically significant difference from each other. Based on the "polygenic" models, the estimated intraclass correlation is 0.132 (+/- 0.035) for FEV1 and 0.171 (+/- 0.039) for MMFR, and the narrow-sense heritability is 0.264 for FEV1 and 0.342 for MMFR. Segregation analysis shows that the "mixed" model with both single locus and polygenic components had a better fit for FEV1 than single-locus or polygenic only models. However, the model which included a nontransmitted environmental factor [tau(AA) = tau(AB) = tau(BB) = qA] and polygenic loci had a better fit than the Mendelian model [tau(AA) = 1, tau(AB) = 1/2, tau(BB) = 0] [Akaike's information criterion (AIC) = 2219.47 vs. AIC = 2222.14]. For MMFR, the Mendelian "mixed" model gave a nonsignificant improvement in loge likelihood compared to the simple polygenic model. Comparison of the single-locus model and Mendelian "mixed" model shows no difference in fitting the data. This study suggests that FEV1 and MMFR are controlled by many loci with no major effects and/or common environmental factors.

Prevalence of chronic obstructive pulmonary disease in elderly Finns

The prevalence of chronic obstructive pulmonary disease (COPD) in the elderly is poorly known. The aim of this study was to determine the prevalence of COPD and to analyse the factors associated with it in an elderly Finnish population. The population consisted of persons resident in Lieto, Finland, born in or before 1926. One thousand one hundred and ninety-six individuals (488 men and 708 women, 93% of those eligible) participated in the survey, which was carried out in 1990-91 at the Lieto Health Centre. The methods included a nurse's interview and spirometry with a bronchodilator test. The participants were also clinically examined, and the number of subjects with COPD was determined using simple diagnostic criteria. Sixty-one men and 21 women with COPD were found. Thus the prevalence was 12.5% for the men and 3.0% for the women. In both sexes only about 2% of those who had never smoked suffered from COPD, but among the current smokers the prevalence was 35% for the men and 13% for the women. In a stratified analysis COPD was commonest among those with a low social status and histories of smoking and working in dusty occupations. In a majority the obstruction was only minimally reversible when tested with salbutamol inhalation. The study confirmed that the prevalence of COPD in the elderly with negative histories of smoking is low, and emphasizes the importance of reducing smoking as the only effective preventive measure.

The influence of smoking cessation on body weight may be temporary

The relationships of bodyweight and body mass index with smoking cessation were examined among 1633 adults in Humboldt, Saskatchewan, Canada. Mean body mass index was highest in ex-smokers and lowest in smokers, and that of non-smokers was intermediate. Body mass index decreased significantly with increasing years after smoking cessation in female ex-smokers after adjusting for age, education, location of work, and physical activity. This trend, however, was not significant in men. The body weight data showed similar results. The prevalence of obesity (body mass index greater than 30 kg/m2) in all subjects showed a decrease with increasing years after smoking cessation.

Body weight and weight gain related to pulmonary function decline in adults: a six year follow up study

BACKGROUND

Obesity increases the risk of cardiovascular disease, hypertension, diabetes, digestive diseases, and some cancers. Several studies have shown that excess weight or weight gain is related to pulmonary dysfunction, but this issue needs to be further clarified.

METHODS

The analysis was based on data of the Humboldt cohort study which was conducted in the town of Humboldt, Saskatchewan, Canada. The baseline survey in 1977 included 1202 adults, comprising 94% of all residents aged 25-59 years. Of these, 709 (59%) were followed up in 1983. Pulmonary function (forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and maximal mid expiratory flow rate (MMFR) and weight were measured in both surveys. Weight gain was determined by subtracting weight at baseline from weight at follow up. A residual analysis was used to examine the relationship between body mass index (BMI) at baseline, weight gain, and pulmonary function decline.

RESULTS

Both BMI at baseline and weight gain were significantly related to pulmonary function at follow up. The effect of weight gain during the study period, however, was more prominent. The results showed that both mean residual FVC and FEV1 were highest in the group that gained < 1.0 kg, lowest in the group that gained > or = 4.0 kg, and intermediate in the group that gained 1.0-3.9 kg in both men and women after taking age, BMI at baseline, and smoking into account. The effect of weight gain on pulmonary function was greater in men than in women. Multiple regression analysis showed that each kilogram of weight gain was associated with an excess loss of 26 ml in FVC and 23 ml in FEV1 in men, and 14 ml and 9 ml respectively in women.

CONCLUSIONS

Weight gain is significantly related to lung dysfunction. The effect of weight gain on pulmonary function is greater in men than in women.

Relationship between pulmonary test variables and asthma and wheezing: a validation of self-report of asthma

We investigated the relationship between the pulmonary test variable measurements and self-reported asthma and wheezing from a cross-sectional study conducted in Saskatchewan. Based on the responses to the questionnaire, the subjects were classified into asthmatic, wheezing, and asymptomatic groups. For both male and female subjects the mean values of forced expiratory volume in 1 s (FEV1), forced expiratory flow during the middle half of the forced vital capacity (FEF25-75), and FEV1/FVC ratio were lowest in asthmatics, followed by wheezing and asymptomatic groups, respectively. This trend was also observed in forced vital capacity (FVC) for men but not for women. After adjusting for current smoking status, the trend in the means across the three groups was statistically significant in men for FEV1 (p = 0.03), FEF25-75 (p = 0.002), and FEV1/FVC ratio (p = 0.002) and in women for FEF25-75 (p < 0.001) and FEV1/FVC ratio (p < 0.001). The differences in the adjusted means of FVC, FEV1, FEF25-75, and FEV1/FVC ratio between asymptomatic subjects and the other two groups were significant in both male and female subjects. Significant differences were also observed between asthmatics and wheezing groups in the adjusted means of FEF25-75 and FEV1/FVC ratio in male and female subjects. We conclude that the self-report of asthma has a high level of validity against the criterion of concurrently measured pulmonary test variables.

Association of asthma with use of pesticides. Results of a cross-sectional survey of farmers

We investigated the association of self-reported asthma and pesticide use in 1,939 male farmers. Regardless of age, smoking pack-years, and nasal allergic reactions, the prevalence of asthma was significantly associated with the use of carbamate insecticides (prevalence odds ratio = 1.8, 95% confidence interval: 1.1 to 3.1, p = 0.02). Self-reported asthmatics, in comparison with nonasthmatics, had significantly lower mean values for lung function test variables after adjusting for age and height and a higher prevalence of respiratory symptoms. These findings raise the possibility that exposure to agriculture chemicals could be related to lung dysfunction in exposed farmers.