Jean-Jacques Laplante

Prevalence and risk factors for chronic bronchitis and farmer's lung in French dairy farmers.

The prevalence of chronic bronchitis and of clinical farmers lung was studied in 30 districts of the French Doubs province in relation to individual (age, sex, smoking) and geographical (altitude) factors. 5703 exclusively dairy farmers (response rate 83%) participated in the study by answering a medical questionnaire. Prevalences of chronic bronchitis and clinical farmers lung were 9.3% and 1.4% respectively. A logistic regression model was used to evaluate risk factors for chronic bronchitis and clinical farmers lung. A risk of chronic bronchitis was associated with male sex (p < 10(-4)), age (p < 10(-4)), smoker category (p < 10(-4)), and altitude (p < 10(-4)). A risk of clinical farmers lung was associated with non-smokers (p < 0.05), and linearly with altitude (p < 10(-4)). Also there was a strong positive relation between chronic bronchitis and clinical farmers lung (odds ratio 19.5 (95% confidence interval 12.1-31.4) after adjustment for confounding variables. The main finding of this study is the highly significant increase of prevalence of the diseases in relation to altitude.

Six year longitudinal study of respiratory function in dairy farmers in the Doubs province

A previous study, carried out in 1986 in France, showed the prevalence of respiratory symptoms and of respiratory function impairment to be higher in dairy farmers than in a control group of nonexposed subjects living in a rural zone. In order to confirm the harmful effect of dairy farming, the two groups were re-studied 6 yrs later at the same period of the year. One hundred and ninety-four (77.6%) farmers and 155 (62%) control subjects were available for re-examination. Non-re-evaluated subjects were comparable to re-evaluated subjects for age, sex, smoking and respiratory symptoms and function at initial evaluation. Dairy farmers consistently had more respiratory symptoms and lower levels of respiratory function than did control subjects. In the study populations as a whole, the mean annual decline in vital capacity (VC) and forced expiratory volume in one second (FEV1) was slightly, but nonsignificantly, higher in farmers than in control subjects: in mL x yr(-1) (SD), -43.1 (68.2) versus -37.9 (60.2) for VC and -32.8 (56.7) versus -30 (47.2) for FEV1. There was a positive interaction between farming and age (i.e. duration of exposure in this cohort) on respiratory function decline, and in male subjects aged > or = 45 yrs, dairy farming was associated with an accelerated loss in VC (p<0.05) and FEV1 (p<0.05) after controlling for age, smoking, height and geographic location in a multiple linear regression model. Initial values of respiratory function, age and pack-years smoked (only for VC) were the other variables found to be significant determinants of decline in lung function. In conclusion, this study mainly suggests that dairy farming is associated to a very moderate accelerated loss in respiratory function that increases with duration of exposure and is significant in older male subjects.

Respiratory status in dairy farmers in France; cross sectional and longitudinal analyses.

Aims: To compare respiratory status in dairy farmers with that of non-farming controls. Methods: Longitudinal study in the Doubs (France). From a cohort constituted in 1994 (T1), 215 (81.1%) dairy farmers and 110 (73.8%) controls were reevaluated in 1999 (T2). The protocol comprised a medical and occupational questionnaire, spirometric tests at both evaluations, allergological tests at T1, and a non-invasive measure of blood oxygen saturation (Spo2) at T2. Results: In 1999 analyses, the prevalence of chronic bronchitis was higher (p = 0.013), and FEV1/VC (p < 0.025) and Spo2 (−0.7%, p < 0.01) lower in dairy farmers than in controls. In a multiple linear regression model, farming, age, and smoking were significantly and inversely correlated with Spo2. In the whole population, the mean annual decline in FEV1 and FEV1/VC was −13.4 ml and −0.30%, respectively. Farming was associated with an accelerated decline in FEV1/VC (p < 0.025) after adjustment for covariates. No relation between allergy and respiratory function changes was observed, except for FEF25–75. Conclusions: This prospective study shows that dairy farming is associated with an excess of chronic bronchitis, with a moderate degree of bronchial obstruction and a mild decrease in Spo2.

Longitudinal study of respiratory health in dairy farmers: influence of artificial barn fodder drying

Factors influencing respiratory consequences of dairy farming have not been extensively investigated to date. To evaluate the effects of barn fodder drying on respiratory symptoms and lung function, a 5 yr follow-up study was performed in the Doubs (France). A cohort of male dairy farmers was analysed in 1990. The initial cross-sectional results suggested that barn-drying fodder may protect dairy farmers from lung function impairment. In 1995, 113 barn-drying farmers (92%) and 231 traditional-drying farmers (84%) were re-analysed. Barn and traditional fodder-drying farmers were compared for prevalence of symptoms and spirometric measures of lung function. After controlling for age, smoking status, altitude and cumulative exposure, barn-drying farmers compared to traditional-drying farmers had a lower prevalence of chronic bronchitis (4 versus 10%; p<0.05) and slightly higher values of forced expiratory volume in one second (FEV1) (p=0.06) and FEV1/vital capacity (VC) (p<0.01). Nevertheless, decline of the respiratory function parameters was not significantly different between the two groups. Variables positively and significantly associated to longitudinal decline of lung function parameters were: age (FEV1, FEV1/VC); altitude (VC, FEV1) and chronic bronchitis and dyspnoea at the initial survey (FEV1/VC). Persistence and emergence of chronic bronchitis, dyspnoea and symptoms at exposure were also significantly associated to an acceleration in the annual decline of the respiratory function. In conclusion, the mode of fodder drying does not seem to significantly influence the decline in lung function. Nevertheless, this study confirms the results of the initial cross-sectional analysis and supports the hypothesis that barn drying fodder may have a protective effect on respiratory health in dairy farming.

Twelve-year longitudinal study of respiratory status in dairy farmers.

To evaluate respiratory risk in dairy farmers, the present authors conducted a longitudinal study in the Doubs region of France. From a cohort constituted in 1986 (T1), 157 (62.8%) dairy farmers and 159 (63.6%) controls were re-evaluated in 1998 (T3). The study protocol comprised a medical and occupational questionnaire, spirometric tests at both evaluations, and noninvasive measure of blood oxygen saturation with pulse oximetry (Sp,O2) at T3. In 1998, the prevalence of chronic bronchitis was higher in dairy farmers. In cross-sectional analyses, all respiratory function parameters and Sp,O2 were significantly lower in dairy farmers. In a multiple linear regression model, farming, age, male sex and smoking were significantly and negatively correlated with Sp,O2. However, the mean annual decline in respiratory function parameters did not differ significantly between groups. After adjustment of covariables, accelerated decline in vital capacity and forced expiratory volume in one second was associated with age, smoking and male sex. Decline in vital capacity was accelerated in dairy farmers working in traditional farms and those currently foddering. The current study demonstrates that dairy farming is associated with an increased risk of lung disorders and a decrease in blood oxygen saturation and suggests that respiratory function impairment is correlated with cumulated exposure to organic dusts.

Influence of hay and animal feed exposure on respiratory status: a longitudinal study

Our aim was to study respiratory symptoms and lung function decline in farmers, with particular attention to the influence of handling hay, straw and animal feed. From a cohort recruited in 1993–1994, 219 (82.6%) dairy farmers, 130 (62.5%) nondairy agricultural workers and 99 (66.4%) controls were re-evaluated in 2006. They answered medical and occupational questionnaires, underwent spirometric tests at both evaluations and pulse oximetry in 2006. Dairy and nondairy agricultural workers showed an increased risk for usual morning phlegm (adjusted OR 4.27 (95% CI 1.41–12.95) and 3.59 (95% CI 1.16–11.10), respectively). Animal feed handling was associated with increased risks of wheezing (p = 0.01) and usual morning phlegm (p = 0.04); hay or straw handling was associated with increased risk of wheezing (p = 0.008). Adjusting for smoking, age, height, sex and altitude, dairy farmers had greater declines in forced expiratory volume in 1 s (FEV1)/forced vital capacity ratio (p = 0.01) than controls. An increased decline in FEV1 for all agricultural workers was associated with animal feed handling, both measured as a categorical (currently versus never handling; p = 0.05) or quantitative value (years of exposure during the survey period; p = 0.03). Hay, straw or animal feed handling represents a risk factor of bronchial symptoms and, for animal feed only, of accelerated decline in expiratory flows.

Prevalence and risk factors for COPD in farmers: a cross-sectional controlled study

There are conflicting data regarding the magnitude and determinants of chronic obstructive pulmonary disease (COPD) risk in farmers. In a cross-sectional study of 917 nonfarming working controls and 3787 farmers aged 40–75 years, we assessed respiratory symptoms, tobacco exposure, job history (without direct exposure measurement) and lung function. COPD was defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criterion (post-bronchodilator forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) <0.70) and by the Quanjer reference equation (post-bronchodilator FEV1/FVC <lower limit of normal (LLN)). The prevalence (95% CI) of COPD according to the GOLD criterion was 5.1% (4.4–5.8%) and 2.9% (1.8–4.0%) in farmers and controls, respectively (p=0.005), and 3.1% (2.5–3.6%) and 1.5% (0.7–2.3%), respectively, for the LLN criterion (p<0.01). For both COPD criteria after adjustment for age, sex and smoking status, COPD prevalence was similar in controls and crop farmers. Compared to controls, four job categories had a higher prevalence of COPD according to the GOLD criterion, namely, cattle breeders, swine breeders, poultry breeders and breeders of two or more livestock types. Among cattle breeders, only those from Franche-Comté had higher prevalence of COPD according to both GOLD and LLN criteria. The prevalence of COPD in farmers is higher than in nonfarming working controls, and depends on the farming activity, the region and the criterion used to define COPD. Prevalence of COPD is higher in agricultural workers than in nonfarming working control subjects http://ow.ly/RUYe8

Impact of farm modernity on the prevalence of chronic obstructive pulmonary disease in dairy farmers

Dairy farming is associated with an excess of chronic obstructive pulmonary disease (COPD). The dairy industry has been changing for the past three decades with larger, more efficient farms and potentially less exposure to agents involved in COPD development. However, the impact of farm modernisation on COPD prevalence is unknown. We studied respiratory symptoms, respiratory function by spirometry and tobacco smoking in 575 male dairy farmers working either in traditional or in modern farms in the French Doubs region. COPD was defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criterion (forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) <0.70) and by the Quanjer reference equation (FEV1/FVC<lower limit of normal (LLN)). Modern farms were defined either as having a separation between the house and the cowshed (model 1) or as having a loose housing system for the animals (model 2). The prevalence of COPD in dairy farmers was 12.0±2.7% (GOLD), and 5.6±4.1% (LLN definition). By multivariate analysis using the LLN definition, tobacco smoking (OR (95% CI) 3.96 (1.53 to 10.3) and 3.42 (1.32 to 8.84) for models 1 and 2, respectively) and characteristics of traditional farms (1.97 (1.02 to 4.47) and 5.20 (1.73 to 15.64) for models 1 and 2, respectively) were associated with higher COPD prevalence. Working in a traditional farm plus current smoking had an additive effect on COPD prevalence in model 1 and a synergistic effect in model 2. These findings support a positive impact of farm modernity on COPD prevalence in dairy farmers. Occupational and smoking-related risk factors are of nearly the same magnitude.

Predictors of early cessation of dairy farming in the French Doubs province: 12-year follow-up†

BACKGROUND A healthy worker effect due to respiratory disability has been noted in the farming population, but other factors may also interfere. Little has been published about factors influencing the early cessation of work in self-employed dairy farmers. METHODS Two hundred and nineteen dairy farmers were included from a cohort constituted in eastern France in 1993-1994 with a 12-year follow-up. Spirometric data, personal, and farm characteristics were registered. Cox models with delayed entry in which age was the time-scale were applied to identify the baseline predictive factors of the early cessation of dairy farming. RESULTS Working in a modern farm was protective against early cessation of dairy farming (hazard ratio: 0.36 [95% CI: 0.16-0.81]), especially in men. Having asthma was a predictive factor of early cessation, especially in women (hazard ratio: 16.12 [95% CI: 3.28-79.12]). CONCLUSIONS The most predictive factors of early cessation of dairy farming were health related in women and farm related in men.

Smoking habits in French farmers: a cross-sectional study

BackgroundFarmers are exposed to multiple air contaminants that may interact with tobacco smoking in the development of respiratory diseases. Farmers are currently considered to smoke less than non-farmers, but precise data in different categories of age and farming activities are lacking.MethodsSmoking habits were studied in a cross-sectional study involving 4105 farmers and 996 non-farming controls aged 40–74 years in 9 French departments between October 2012 and May 2013. Three age groups were defined (40–54, 55–64 and 65-74years). Farmers were divided into four activity groups, namely cattle breeders, livestock farmers working in confined spaces, crop farmers and others. Smoking prevalence was compared between farmers and controls, and odds ratios (ORs) for smoking adjusted for age were calculated.ResultsThe adjusted OR for ever-smoking was lower among farmers than among non-farmers in all age categories, but the ORs for current smoking were similar in farmers and controls. Smoking prevalence varied according to the type of farming activity, and was lower than in non-farming controls only among cattle breeders and confined livestock farmers. In farmers, the proportion of smokers was higher in the youngest age categories compared with the older age classes.ConclusionsOur results confirm that the prevalence of ever-smokers is lower in farmers than in non-farmers. Nevertheless, our data show that active smoking prevalence is similar in farmers and in non-farmers. This suggests that farmers, just like non-farmers, should be targeted by primary prevention campaigns against smoking.