Quantitative and qualitative evaluation of spirometry for COPD screening in general practice.

INTRODUCTION: Proper diagnosis of COPD remains a challenge. Spirometry testing in primary care may help to reduce misdiagnosis, but its reliability as a diagnostic instrument needs to be assessed. OBJECTIVES: To investigate (1) the validity of spirometry testing performed in primary care and (2) the accuracy of the diagnostic of airflow limitation obtained by these tests. METHODS: Subjects attending a COPD screening programme had screening spirometry performed either by general practitioners (GPs) or by trained nurses or technicians, who had all received two 3-hour training sessions. Subjects with airflow limitation and a subset of subjects with normal spirometry at screening were invited to undergo confirmatory spirometry performed by trained nurses in a pulmonary function laboratory. RESULTS: Of the 4610 subjects who attended the screening sessions, 96.5% had a valid screening spirometry test. A total of 392 subjects attended the confirmatory sessions. Values measured by screening spirometry were satisfactory compared with those of confirmatory spirometry (rc=0.83). Taking confirmatory spirometry as reference, the positive predictive value of screening spirometry for the diagnosis of persistent airflow limitation was 93% with a specificity of 95%. Agreement for the diagnosis of persistent airflow limitation was substantial (k=0.80). CONCLUSION: Spirometry performed in primary care by trained personnel reliably identifies persistent airflow limitation. This may encourage pulmonologists to collaborate with primary care providers with the aim of improving appropriate diagnosis of COPD.

[COPD in dairy farmers: screening, characterization and constitution of a cohort. The BALISTIC study]. / BPCO des producteurs laitiers : dépistage, caractérisation et constitution d'une cohorte. Étude BALISTIC.

BACKGROUND: A pilot study from our group suggests that the prevalence of chronic obstructive pulmonary disease (COPD) among dairy farmers is higher than in the general population although dairy workers are less frequently smokers. OBJECTIVES AND METHODS: The study presented here aims at (i) determining the prevalence of COPD in a large and representative population of dairy farmers; (ii) characterizing these patients in terms of smoking habits, dyspnoea, quality of life, lung function, bronchial exhaled nitric oxide, systemic inflammation, arterial stiffness and exercise capacity; (iii) comparing characteristics of dairy farmers' COPD with the characteristics of COPD in patients without any occupational exposure; (iv) identifying the etiological factors of COPD in dairy farmers; and (v) constituting a cohort of COPD patients and control subjects for further longitudinal studies. Two groups of COPD patients (dairy farmers or not) and two groups of controls subjects will be selected among a representative panel of 2000 dairy workers and 2000 subjects without any occupational exposure, all aged 40 to 75 years. EXPECTED RESULTS: A better knowledge of the epidemiology and pathophysiology of COPD in dairy farmers should guide a specific strategy of prevention. The knowledge of the characteristics of COPD occurring in dairy farmers will help to define the therapeutic modalities that might be different compared with the therapeutic recommendations for COPD secondary to tobacco smoking.

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 (FEV(1))/forced vital capacity ratio (p = 0.01) than controls. An increased decline in FEV(1) 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.

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 (S(p,O(2))) at T3. In 1998, the prevalence of chronic bronchitis was higher in dairy farmers. In cross-sectional analyses, all respiratory function parameters and S(p,O(2)) were significantly lower in dairy farmers. In a multiple linear regression model, farming, age, male sex and smoking were significantly and negatively correlated with S(p,O(2)). 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 occupational factors on lung function in French dairy farmers. A 5-year longitudinal study.

BACKGROUND: Dairy farming is associated with a high prevalence of respiratory disorders but the respective influence of occupational exposures, environmental, and individual factors on lung function remain unclear. METHODS: In 1994 and 1999, dairy farmers were examined in the Doubs province, France. Spirometric measures and allergological tests were performed. Medical and professional data were obtained by questionnaires. A multiple linear regression analysis was performed. RESULTS: An accelerated decline in lung function parameters was associated with age, male sex, traditional farm (as opposed to modern farms), and a high rate of total IgE (P < 10(-2)). Blood oxygen saturation (SpO2) was significantly positively linked with the modernization of the farm and negatively with age, smoking status, and log IgE (P < 10(-2)). Geographical factors (altitude and climatic conditions) had no significant effect. CONCLUSIONS: The modernization of the farm has an important and beneficial impact on lung functiony.

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.

Relationships of immunoglobulins E and G sensitization to respiratory function in dairy farmers.

An impairment of respiratory function has been demonstrated in dairy farmers. The objective of this study was to evaluate the relationship of allergy to respiratory function in dairy farmers in a longitudinal study conducted in the Doubs (France). A cohort of male dairy farmers constituted in 1990 was re-evalued in 1995. Subjects completed a medical and occupational questionnaire, and a spirometry test in both 1990 and 1995, in 1995 they were also subjected to immunological tests. Relationships between immunological variables and respiratory function were studied by a multiple linear regression model adjusted for age, smoking status, respiratory symptoms, altitude and occupational exposure. Amongst the 394 subjects of the initial cohort, 330 were included in the longitudinal study and 320 had immunological tests. Log immunoglobulin (Ig) E was negatively correlated with the 1995 respiratory function parameters (p<0.05 for forced expiratory volume in one second (FEV1) and FEV1/vital capacity (VC). Immunoglobulin (Ig) G response to Aspergillus fumigatus detected by enzyme-linked immunosorbent assay (ELISA) was negatively correlated to 1995 respiratory function parameters (VC: p<0.01; FEV1: p<0.001; FEV1/VC: p<0.01). There was a positive relationship between IgG antibodies against Aspergillus fumigatus and the mean annual decline in FEV1 (p<0.01) and FEV1/VC (p<0.01). To conclude, allergy may play a role in the impairment of respiratory function in dairy farmers of the Doubs and sensitization to Aspergillus fumigatus seems to constitute an independent risk factor for the development of airflow obstruction in this occupational setting.

Prevalence of asthma and respiratory symptoms in dairy farmers in the French province of the Doubs.

With the aim of determining whether dairy farming is associated with an excess of asthma and respiratory symptoms, we compared the respiratory status in a sample of dairy farmers (n = 265) and a control group of nonexposed subjects (n = 149). The study protocol comprised a questionnaire, spirometry, and a bronchodilatation test (400 micrograms salbutamol powder), and an allergological evaluation: serum total IgE level, Phadiatop test, and skin prick tests (SPT) for seven inhalant allergens. Cumulative prevalences of self-reported asthma and of current asthma were respectively 5.3% and 1.5% in farmers, and respectively 3.4% and 1.3% in control subjects (both NS). Prevalences of all the respiratory symptoms studied were higher in farmers, with statistically significant differences after adjusting for age, sex, and smoking, for wheezing ever (OR: 2.7, p < 0.05), wheezing within the last year (OR: 5.2, p < 0.025), usual morning cough (OR: 5, p < 10(-)3), usual morning phlegm (OR: 11.3, p < 10(-)4), and chronic bronchitis (OR: 11.8, p < 0.01). The effect of exposure on these symptoms was more pronounced than, or of the same magnitude as that of smoking. Smoking and exposure had an additive effect except for chronic cough for which a positive interaction was observed (p = 0.05). Mean FEV1/VC (percentage of predicted) was statistically negatively correlated to dairy farming (p < 0.025) after adjusting for confounders. Bronchial obstruction was reversible in about 10% of subjects in both groups. In conclusion, this study mainly demonstrated an excess of respiratory symptoms in dairy farmers which is weak and nonsignificant for asthma, and high for cough, phlegm, and chronic bronchitis. It also suggested that the combined effect of farming and smoking was synergistic on chronic cough.

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.

[Respective influence of occupational and personal factors on respiratory function in dairy farmers]. / Influence respective des facteurs professionnels et personnels sur la fonction respiratoire en milieu agricole de production laitière.

Occupational and individual factors influencing respiratory function were analysed in a sample of dairy farmers. The study protocol included a medical questionnaire, an occupational questionnaire, spirometry and allergological tests (skin prick tests for a panel of inhalant allergens, serum total IgE level and Phadiatop (CAP System). Two hundred and forty-five farmers were studied (140 men, 105 women with an average age of 45.9 (11.3) years, 35 were smokers, 27 ex-smokers and 183 non-smokers). A multiple linear regression model was used to analyse the correlations between respiratory function and the different independent variables. There was a statistically significant negative correlations between smoking (expressed in pack-years) and all the respiratory function parameters (p < 0.01). Respiratory function was significantly impaired in farmers working on traditional farms (p < 0.05 for VC and for FEV1), and the respiratory function values increased proportionally with the modernisation of the farms (notably using an artificial barn drying system for hay and a ventilation system for the cow byres). No significant relationship between respiratory function and quantitative indicators of exposure (size of farm, amount of livestock, quantity of hay handled during professional lifetime) or indicators of IgE-mediated allergy was observed. In conclusion, this study suggests that traditional work conditions in farms which have little mechanisation are, along with tobacco, the determining factors for the respiratory function impairment in dairy farmers.

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.

[Prevalence of immediate allergy to respiratory allergens in fodder farmers in Doubs]. / Prévalence de l'allergie immédiate aux pneumallergènes chez les agriculteurs fourragers du Doubs.

The Doubs is a damp, semi-mountainous fodder farming department in which occupational respiratory diseases (including asthma) are common in farmers. We studied the prevalence of IgE-mediated allergy (total IgE, Phadiatop and skin prick tests) in a group of 265 exclusive dairy farmers of both sexes of the department and in a control group of non exposed, administrative workers living in the same area. Skin prick tests were: Dermatophagoides pteronyssinus, Acarus siro, cat hair, cow danders, grass pollens, betullacea pollens (trees from the East of France), and hay extracts from the Doubs. Total IgE were higher than 180 KUI/l in 26 (9.9%) farmers and in 15 (10.5%) controls (NS). Phadiatop was positive in 41 (15.7%) farmers and in 27 (19%) controls (NS). Prevalence of positive skin prick tests (at least one) in farmers and controls was respectively 36% and 40% (NS). Farmers were more frequently sensitized to hay extracts (OR = 1.7), cow danders (OR = 1.3) and less frequently to cat hair (OR = 0.63) than controls but the differences were not statistically significant. In conclusion, this study fails to give evidence of a risk of IgE-mediated allergy to work-related and other common inhalation allergens in dairy farmers the Doubs.

Seroepidemiologic screening of Echinococcus multilocularis infection in a European area endemic for alveolar echinococcosis.

In a serologic survey for Echinococcus multilocularis infection, we screened sera from 7,884 subjects from the Doubs Departement in France, an area endemic for alveolar echinococcosis (AE) of the liver. An enzyme-linked immunosorbent assay (ELISA) with a highly species-specific antigen (Em2) and an E. multilocularis crude antigen (Emc) was used for screening. An evaluation of the cost/benefit relationship of this screening, followed by therapeutic management of patients, was made and compared with the actual cost of the follow-up and treatment of the disease in symptomatic cases in this endemic area. Antibody reactions to Em2 and/or Emc made possible the detection of eight asymptomatic clinical cases (seroprevalence averaging 1/1,000), with typical lesions of active AE revealed by abdominal ultrasonography and computed tomography. All were seropositive using the Emc ELISA but two were seronegative using the Em2 ELISA. In five additional seropositive cases, the radiologic investigations revealed small calcified lesions similar to the lesions of abortive AE previously found in Alaska. The cost of this serologic screening program per screened subject and per diagnosed case averaged 50.00 French Francs (FF) (U.S. $8.60) and 60,000.00 FF (U.S. $10,909.00), respectively. The cost of diagnosis, follow-up and treatment of the patients was 5,086.00 FF (U.S. $929.00) per patient per month in the case of diseases diagnosed by the screening program and 7,086.00 FF (U.S. $1,288.00) per patient per month for patients with symptomatic AE. This survey indicates a high prevalence of AE in the target area; it confirms the long latency period of the larval growth in human AE and shows that abortive AE is present in Europe. The use of both the Emc and Em2 ELISAs seems to be better than using the Em2 ELISA alone. The cost of the hospitalization and treatment of the eight screened patients would appear to be relatively high. Even though two of them were asymptomatic, they had very severe forms of the disease. In fact, the total cost was much lower than the actual cost of the disease when diagnosed from clinical symptoms.

Farmer's lung precipitins in Doubs (a department of France): prevalence and diagnostic value.

In a French region where farmer's lung (FL) is common, we determined the prevalence of FL precipitins in dairy farmers and analyzed the relation between the presence of FL precipitins and the clinical probability of the disease. All the exposed dairy farmers of both sexes (n = 2555) from five districts of the Doubs department were asked to respond to a medical and professional questionnaire. A total of 1763 (69%) farmers agreed to participate. Precipitins tests were conducted in 551 (31%) farmers who showed any respiratory symptom and in a random sample of 100 asymptomatic farmers. Serum for each farmer was analyzed by both double diffusion and immunoelectrophoresis against Micropolyspora faeni (MF) and extracts of moldy hay (HE) from Doubs. The 651 farmers were then divided into four groups (G 1-4) with a decreasing probability of FL (G1: typical FL symptoms; G4: asymptomatic farmers). The estimated prevalence of precipitins in the whole population was as follows: 1) by double diffusion, against HE: 83%, against MF: 27%; 2) by immunoelectrophoresis, against HE: 26%, against MF: 19%. There was a close "linear" relation between the prevalence of precipitins detected by immunoelectrophoresis against HE and the symptoms: 51% in G1, 36% in G2, 29% in G3, and 13% in G4. Precipitins detected by immunoelectrophoresis were also related to exposure and geography (more immunization in tableland area than in plain or mountain area). Presence of precipitins detected by double diffusion was not related to symptoms, exposure, or geography.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of barn drying of fodder on respiratory symptoms and function in dairy farmers of the Doubs region of France.

BACKGROUND: A previous study showed there to be fewer microorganisms (especially thermophilic actinomycetes) on farms with artificial barn drying of fodder than on those using traditional storage methods. A cross sectional study was performed to see whether barn drying provides protection against respiratory problems in dairy farmers. METHODS: The respiratory symptoms and function of a group of 123 farmers with daily exposure to cattle foddering from farms which had had a barn drying system for at least three years were compared with those of a representative sample of 274 farmers working in farms with traditional storage in five districts in the Doubs region of France. RESULTS: Both groups were comparable for mean age, weight, height, smoking habits, alcohol consumption, past history of respiratory disease, history of allergy, geographical location of the farm, and length of exposure. Retrospectively estimated exposure to fodder was greater in the group using a barn drying system than in the group working with traditional storage. Acute symptoms at exposure (rhinitis, eye irritation, dry cough, asthma symptoms) and chronic symptoms all tended to be less frequent in the barn drying group, although not individually significantly so. Mean (SD) respiratory function parameters were higher in the barn drying group than in the traditional group: % vital capacity (VC) 104 (14) v 102 (15); % forced expiratory volume in one second (FEV1) 99 (14) v 94 (18); % FEV1/VC 96 (11) v 92 (16); % forced mid expiratory flow (FEF25-75) 87 (24) v 79 (25). CONCLUSION: The results of this cross sectional study suggest that barn drying of fodder may protect respiratory function in dairy farmers.

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

The prevalence of chronic bronchitis and of clinical farmer's 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 farmer's lung were 9.3% and 1.4% respectively. A logistic regression model was used to evaluate risk factors for chronic bronchitis and clinical farmer's 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 farmer's 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 farmer's 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.

[Evaluation of the reliability of the diagnostic methods in farmer's lung]. / Evaluation de la fiabilité des moyens de détection de la maladie du poumon de fermier.

Following a study of the diagnosis of farmer's lung (PDF) carried out in 1763 active farm workers in Doubs, 294 (16.7%) were suspected of PDF and they were invited to a secondary consultation in hospital for a further work up which consisted of a clinical examination for crepitations (RC) on pulmonary auscultation (AP) and for evidence of an interstitial lung disorder (SI) on pulmonary radiograph (RP) and for evidence of a restrictive syndrome (SR) on pulmonary function tests (EFR). 238 patients (80%) accepted the additional assessment and were divided into two groups on the basis of the history and serology (precipitin tests), group 1: probable PDF (n = 65): symptoms suggestive of PDF in the presence of serum precipitins; group 2: possible PDF (n = 173): non specific symptoms with or without serum precipitins. RC were present in 21.9% of patients in group 1 and 6.4% of patients in group 2 (p less than 0.001). There was an SI in 9.2% of patients in group 1 and 4% of patients in group 2 (non significant). For the elevated radiology scores for SI there was a significant difference: 7.7% for SI in group 1 and 1.73% in group 2 (p less than 0.05). There was 38.1% of abnormal EFR in group 1 and 14.7% in group 2 (p less than 0.001) but the difference of the frequency of SR in the 2 groups was not statistically significant (9.5% in group 1 and 4.7% in group 2). In this study, an additional assessment (AP, RP, EFR) carried out at a difficult moment during winter does not appear to confirm great benefit.(ABSTRACT TRUNCATED AT 250 WORDS)