Section of Environment and Radiation, International Agency for Research on Cancer, 150 Cours Albert Thomas, 69372 Lyon CEDEX 08, France; E-Mails: firstname.lastname@example.org (J.S.); email@example.com (G.F.); firstname.lastname@example.org (K.S.).
Int J Environ Res Public Health. 2011 May;8(5):1341-57
AGRICOH is a recently formed consortium of agricultural cohort studies involving 22 cohorts from nine countries in five continents: South Africa (1), Canada (3), Costa Rica (2), USA (6), Republic of Korea (1), New Zealand (2), Denmark (1), France (3) and Norway (3). The aim of AGRICOH, initiated by the US National Cancer Institute (NCI) and coordinated by the International Agency for Research on Cancer (IARC), is to promote and sustain collaboration and pooling of data to investigate the association between a wide range of agricultural exposures and a wide range of health outcomes, with a particular focus on associations that cannot easily be addressed in individual studies because of rare exposures (e.g., use of infrequently applied chemicals) or relatively rare outcomes (e.g., certain types of cancer, neurologic and auto-immune diseases). To facilitate future projects the need for data harmonization of selected variables is required and is underway. Altogether, AGRICOH provides excellent opportunities for studying cancer, respiratory, neurologic, and auto-immune diseases as well as reproductive and allergic disorders, injuries and overall mortality in association with a wide array of exposures, prominent among these the application of pesticides.
BACKGROUND: In a previous study inverse associations between asthma and exposure to fungal spores and endotoxins in atopic farmers and positive associations with the same factors in non-atopic farmers were documented. No external reference population had been included. We, therefore, compared this farming population with the general population from an adjacent region. METHODS: Random samples of a farming (n=2,106) and a rural (n=351) and urban (n=727) general population were selected. Atopy was assessed by serum IgE and asthma by questionnaires. RESULTS: The asthma prevalence was 4.0% among farmers, 5.7% in the rural, and 7.6% in the urban population. Atopy was similar (9-10%). Most asthmatics were not atopic, 67-75%. Farmers had asthma less often than the general population OR 0.52 (95% CI 0.36-0.75); both atopic (OR 0.33 (95% CI 0.15-0.69)) and non-atopic asthma (OR 0.60 (95% CI 0.39-0.93)). CONCLUSION: This may indicate a protective effect of the farm environment on asthma but a healthy worker effect may also play a role.
Our objective was to characterize the association between body mass index (BMI) and childhood asthma while adjusting for individual and neighborhood socioeconomic factors. Data were obtained from 3,804 students 10 to 11 years of age in Nova Scotia, Canada. Asthma was defined as parent-reported doctor-diagnosed asthma or bronchitis. Smoothed curves suggested a linear association between BMI and asthma with a 6 % increase in prevalence per unit increase of BMI. This association was independent of allergies, sex, and socioeconomic factors. Girls from socioeconomically disadvantaged neighborhoods were less likely to be asthmatic as were boys from well-educated and wealthy families.
Reduced asthma and allergy risks in farmers have been ascribed to microbial exposures. However, selection may also play a role and this was assessed in two Scandinavian farming populations.
Asthma prevalence in 739 Danish farming students was compared to that of 1,105 siblings. 8,482 Norwegian farmers were also compared with 349 early retired farmers.
The prevalence of ever-asthma was 5.4% in farming students and 5.2% in siblings (OR 1.1; 95%CI 0.73-1.7). Current asthma in farmers was 3.0% compared to 6.3% in farmers who had retired early (OR 1.8, 95%CI 1.1-2.9). Adjustments for early retirement increased the asthma prevalence by 0.3-0.6%. Farmers who had changed production were more likely to have asthma (OR 9.8, 95% CI 6.0-16).
No healthy worker selection into farming was observed and changes in asthma prevalence due to early retirement were small. Selection effects are therefore unlikely to explain the protective effects of farming on asthma.
Farmers have an increased risk of respiratory morbidity and mortality. The causal agents have not been fully established.
In a cross-sectional study of 4,735 Norwegian farmers, we assessed respiratory symptoms and lung function. Atopy was assessed in a subsample (n = 1,213). Personal exposures to dust, fungal spores, actinomycete spores, endotoxins, bacteria, storage mites, (1-->3)-ss-D-glucans, fungal antigens, organic dust, inorganic dust, silica, ammonia, and hydrogen sulfide were measured for 127 randomly selected farms.
Compared to crop farmers, livestock farmers were more likely to have chronic bronchitis (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.4 to 2.6) and COPD (OR, 1.4; 95% CI, 1.1 to 1.7). FEV(1) (-41 mL; 95% CI, -75 to -7) was significantly reduced, but FVC (-15 mL; 95% CI, -54 to 24) was not. Exposure to most agents were predictors of respiratory morbidity, except FVC. Ammonia, hydrogen sulfide, and inorganic dust were most strongly associated in multiple regression models adjusted for coexposures, but the effects of specific biological agents could not be assessed in multiple regression models because they were too highly correlated. Farmers with atopy had a significantly lower FEV(1) (OR, -87 mL; 95% CI, -170 to -7), but atopy was not directly associated with chronic bronchitis, COPD, and FVC. However, the effects of farming and specific exposures on COPD were substantially greater in farmers with atopy.
Livestock farmers have an increased risk of chronic bronchitis, COPD, and reduced FEV(1). Ammonia, hydrogen sulfide, inorganic dust, and organic dust may be causally involved, but a role for specific biological agents cannot be excluded. Farmers with atopy appear more susceptible to develop farming-related COPD.
Sawmill workers are exposed to wood dust (a well-known carcinogen), microorganisms, endotoxins, resin acids (diterpenes), and vapours containing terpenes, which may cause skin irritation, allergy, and respiratory symptoms including asthma. The health effects of most of these exposures are poorly understood as most studies measure only wood dust. The present study assessed these exposures in the Norwegian sawmill industry, which processes predominantly spruce and pine. Personal exposures of wood dust, resin acids, endotoxin, fungal spores and fragments, mono-, and sesquiterpenes were measured in 10 departments in 11 saw and planer mills. The geometric mean (GM) and geometric standard deviation (GSD) thoracic exposures were: 0.09 mg m-3 dust (GSD 2.6), 3.0 endotoxin units (EU) m-3 (GSD 4.9), 0.4 × 105 fungal spores m-3 (GSD 4.2), 2 × 105 fungal fragments m-3 (GSD 3.2), and 1560 ng m-3 of resin acids (GSD 5.5). The GM (GSD) inhalable exposures were: 0.72 mg m-3 dust (2.6), 17 EU m-3 (4.3), 0.4 × 105 fungal spores m-3 (3.8), and 7508 ng m-3 (4.4) of resin acids. The overall correlation between the thoracic and inhalable exposure was strong for resin acid (rp = 0.84), but moderate for all other components (rp = 0.34-0.64). The GM (GSD) exposure to monoterpenes and sesquiterpenes were 1105 µg m-3 (7.8) and 40 µg m-3 (3.9), respectively. Although mean exposures were relatively low, the variance was large, with exposures regularly exceeding the recommended occupational exposure limits. The exposures to spores and endotoxins were relatively high in the dry timber departments, but exposures to microbial components and mono-and sesquiterpenes were generally highest in areas where green (undried) timber was handled. Dust and resin acid exposure were highest in the dry areas of the sawmills. Low to moderate correlation between components (rp ranging from 0.02 to 0.65) suggests that investigations of exposure-response associations for these components (both individually and combined) are feasible in future epidemiological studies.