Respiratory disorders in agriculture

Glyphosate and environmental toxicity with "One Health" approach, a review

The herbicide Glyphosate (GLY), or N-(phosphonomethyl) glycine was synthesized in 1950 and applied to control weeds in agricultural production. For a long time, it was believed that it was an inert compound, but many studies have instead demonstrated over the years the dangers of GLY to the ecosystem and human health. Among the best-known effects, it is known that GLY interferes with the metabolic pathways of plants and the main groups of microorganisms, negatively influencing their growth. GLY interferes with the metabolic pathways of plants and major groups of microorganisms negatively affecting their growth. The extensive GLY application on fields results in a "slow death" of plants through the minor resistance to root pathogens and in increasing pollution of freshwaters and soils. Unfortunately, however, unlike the old beliefs, GLY can reach non-target destinations, in this regard, ecological studies and environmental epidemiology are of significant interest. In this review, we focus on the effects of acute and chronic exposure to GLY on the health of plants, animals, and humans from a One Health perspective. GLY has been linked to neurological and endocrine issues in both humans and animals, and behavioral modification on specific bioindicators, but the knowledge about the ratio cause-and-effect still needs to be better understood and elucidated. Environmental GLY residues analysis and policy acts will both require new criteria to protect environmental and human health.

Lung inflammation from repeated exposure to LPS and glyphosate

Agricultural workplaces consist of multiple airborne contaminants and inhalation exposures induce respiratory effects in workers. Endotoxin (LPS) and glyphosate are two common airborne contaminants in agricultural environments. We have previously shown that exposure to a combination of LPS and glyphosate synergistically modulates immune reactions as compared to individual exposures. The immunopathogenesis of acute and chronic exposure to complex agricultural exposures including LPS and glyphosate is not known; therefore, we further investigated the lung cellular inflammatory differences in mice exposed to either a combination, or individual, LPS, and glyphosate for 1 day, 5 days, and 10 days. Exposure to a combination of LPS and glyphosate resulted in greater cellular inflammatory effects in lungs as compared to individual exposures to LPS or glyphosate. Repeated exposures to the combination of LPS and glyphosate resulted in robust infiltration of inflammatory cells in the perivascular, peribronchiolar, and alveolar regions, and increases of alveolar septal thicknesses and perivascular spaces in the lungs with intense intercellular adhesion molecule (ICAM) - 1 staining in the perivascular region, but minimal staining in the pulmonary artery endothelium.

A comprehensive review of levels and determinants of personal exposure to dust and endotoxin in livestock farming

The respiratory health effects of livestock farming have been on debate for more than three decades. Endotoxin-contaminated organic dusts are considered as the most important respiratory hazards within livestock environments. A comprehensive review of the knowledge from studies assessing the exposure status of livestock farmers is still to be published. The present study reviews research published within the last 30 years on personal exposure of livestock farmers to organic dust and endotoxin, focusing on studies on pig, poultry and cattle farmers. Applied measurement methods and reported levels of personal exposure for the total, inhalable and respirable fractions are summarized and discussed, with emphasis on the intensity of exposure and the size and distribution of the reported exposure variability. In addition, available evidence on potential determinants of personal exposure to dust and endotoxin among these farmers are documented and discussed, taking results from exposure determinant studies using stationary sampling approaches into consideration. Research needs are addressed from an epidemiological and industrial hygiene perspective. Published studies have been heterogeneous in design, and applied methodologies and results were frequently inadequately reported. Despite these limitations and the presence of an enormous variability in personal exposure to dust and endotoxin, no clear downward trends in exposure with time were observed, suggesting that working environments within stables remains largely uncontrolled. Exposure control and prevention strategies for livestock farmers are urgently required. These should focus on the development of novel and improved methods of controlling dust and endotoxin exposure within stables based on the currently available knowledge on determinants of exposure.

Asthma increase among farmers: a 12-year follow-up

Respiratory disease is a well known health hazard for farmers, but the long-term prognosis is less well known. This is a 12-year follow-up of an investigation of Swedish farmers, most of them dairy farmers. A questionnaire was mailed to all 418 farmers who were alive of the farmers originally participating in 1982. They were invited to an interview, spirometry, and blood sampling. Ninety-one per cent (380) of the farmers, 321 men and 59 women, responded to the questionnaire. The mean age was 56 years for the men and 55 years for the women. Of the group, 10% were smokers, 25% ex-smokers, and 65% had never smoked. The population estimate for asthma in the farmers was 8.9% in 1994 compared to 2% in 1982, and to 5.4%-6.6% in the general population in the region in 1982. Of the asthmatic subjects, one-third had positive RAST tests (radioallergosorbent tests). Almost 90% of the new onset asthma cases since 1982 had non-IgE-mediated asthma. Most of the IgE-mediated asthmatics had had symptoms for many years, while 70% of the non-IgE-mediated asthmatic farmers had no or only wheezing with colds 1982. Two new cases of hypersensitivity pneumonitis were identified, and 7.3% had experienced inhalation fever during the last 12 years. In general, individuals with asthma and chronic bronchitis who had left farming were in better health in 1994 as compared to 1982. In conclusion, farmers have an enhanced risk to develop asthma increasing with age. Asthma in farmers is often non-IgE-mediated.

Excess longitudinal decline in lung function in grain farmers

Workers in intensive agricultural operations are exposed to dust and endotoxin that are associated with respiratory effects. The authors investigated the longitudinal changes in lung function in male grain farmers. In this study, male grain farmers (n = 263) and male nonfarming control subjects (n = 261) studies initially in 1990/91 were followed-up in 1994/95 and 2003/04. After controlling for potential confounders, grain farmers had an excess annual decline of 9.2 ml/year (95% confidence interval [CI]: 2.7, 15.8, p = .006) in forced vital capacity (FVC) in comparison to control. Long-term exposure to grain dust and other substances in lifetime grain farmers results in progressive loss in lung function.

Behavior change, environmental hazards and respiratory protection among a southern farm community

The agricultural industry ranks as one of the most dangerous in terms of occupational deaths and injuries. A wide variety of respiratory illnesses can result from the exposure to grain and organic dusts and working in animal confinement facilities and barns. This article analyzes the Transtheoretical Model of Change for implications relevant to health promotion and education. This study explored differences of perception of occupational health, environmental exposures, and stages of change consistent with the readiness to take action and the confidence to act toward respiratory health among farmers who report respiratory symptoms with physical activity and those who do not. A convenience sample of 123 farm owners and agricultural employees recruited from community-based agricultural events in southeast and central Louisiana completed three surveys: (a) Health Risk and Environmental Assessment; (b) Identification of Respiratory Mask Use; (c) Stage of Awareness and Preventive Respiratory Health; and demographic information. Subjects performed pulmonary function tests including three Forced Vital Capacity (FVC) maneuvers while connected to a Renaissance spirometer. Even though the majority of subjects rated themselves in action stage of change, subjects reported using respiratory protective devices less than 10% of the time. No significant differences were found in environmental exposures. Using chi-square analysis, those farmers who reported breathlessness were significantly more likely to report fatigue, chest pain, and dizziness. Those farmers who report breathlessness are significantly less likely to perceive respiratory health as important compared to other occupational illnesses/conditions. There is a need for additional studies to further examine the relationship between respiratory symptoms, exposure risks, and behavior change theory.

Pulmonary Exposure to 1→3-β-Glucan Alters Adaptive Immune Responses in Rats

1 --> 3-beta-glucans have been associated with increased pulmonary inflammation in fungal-related indoor air problems. Epidemiological studies have shown a correlation between increases in T-cell proliferation and decreases in CD4+/CD8+ ratio after exposure to fungi. The objective of the present investigation was to determine the mechanisms by which 1 --> 3-beta-glucans affect immune responses using an animal model. Rats received a single dose of zymosan A (2.5 mg/kg body weight) via intratracheal instillation (IT) and were euthanized on days 1, 4, 6, 8, and 10 post IT. Bronchoalveolar lavage was performed at each time point post-IT. Inflammation and lung injury were assessed by measuring neutrophil infiltration into bronchoalveolar lavage fluid (BALF) and by measuring albumin and lactate dehydrogenase levels in BALF, respectively. Alveolar macrophage activation was determined by chemiluminescence. Immune response was characterized via immunophenotyping of bronchoalveolar lavage cells and lymphocytes isolated from the lung-associated lymph nodes. Upon challenge with zymosan, rats exhibited increased inflammation and injury at early time points (days 1 and 4) post IT exposure. Although elevations in neutrophil infiltration and chemiluminescence had returned to control levels on day 4, lymphocytes recovered from lung-associated lymph nodes continued to proliferate and reached a maximum on day 6. The CD4+/CD8+ T cell ratio from lymph nodes was lower in zymosan-treated rats than in control rats. Zymosan treatment increased tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-10, and IL-12p70 secretion in BALF on day 1. In summary, rats exposed to zymosan had an increase in acute inflammation, and the altered lymphocyte profiles were consistent with the findings of epidemiology studies.

Respiratory disorders are not more common in farmers. Results from a study on Icelandic animal farmers

RATIONALE

The current prevalence of respiratory disorders and symptoms in Icelandic farmers is unknown, but a high prevalence of respiratory symptoms has been reported in the past. Modern farming practices have been implemented in Iceland in the past decade and the processing of hay has changed markedly leading to less organic dust exposure.

OBJECTIVE

The aim was to estimate the prevalence of respiratory disorders and symptoms in a nationwide study of Icelandic farmers.

METHODS

We conducted a questionnaire-based study of all Icelandic farmers with a comparison group randomly selected from the national citizen registry of Iceland. The questionnaire included items regarding respiratory symptoms and disorders.

RESULTS

Out of 2042 farmers invited to participate, 1107 responded (54%), as did 689 of 1500 controls (46%). Farmers were slightly older and more likely to be male (87% vs. 47%). Smoking rates were significantly lower among farmers than among controls. The prevalence of asthma was not significantly different between the two groups, with a lifetime prevalence of 9.4% (n=104) among farmers compared to 10.2% (n=70) among controls. Medication use for asthma was not significantly different. The prevalence of self-reported, physician-diagnosed chronic bronchitis and emphysema likewise did not significantly differ between the groups, but self-reported hay fever was significantly more prevalent among farmers.

CONCLUSION

The prevalence of respiratory disorders and symptoms among Icelandic farmers is currently similar to non-farmers. This may suggest that modernization of the agricultural environment has had a positive effect on workers' health.

Lung health in workers exposed to reed dust

We conducted a cross-sectional survey in a cellulose plant among 109 reed workers, exposed to reed dust and 78 unexposed office workers, to investigate respiratory health effects of reed dust exposure. Investigations included dust measurements, serum total IgE, skin prick test, pulmonary function testing and questionnaire on respiratory symptoms. Total dust level in the reed processing unit was higher than the office (9.7 and 0.02 mg/m3, respectively). Reed workers had a higher rate of current smoking (67% and 46%, respectively). After the adjustment for smoking status and age, reed dust exposure was significantly associated with wheezing, chronic cough, dyspnea, itching eyes and itching nose. Chest tightness and ODTS symptoms were only reported by reed workers (27.5% and 23.9%, respectively). After the adjustment for pack-years of smoking, percentage of predicted FEV1, FVC, FEV1/FVC and FEF25-75 in reed workers were significantly lower than office workers. Among reed workers, wheezing was associated with older age (>40 years) and ever smoking, and cross-shift decline in FVC and FEV1 with shorter duration of work. Reed dust exposure in the workplace could provoke respiratory symptoms, possibly due to an irritating effect. Health selection bias is likely, and could have underestimated the health effects of reed dust exposure.

Allergic rhinitis, asthma, and atopy among grape farmers in a rural population in Crete, Greece

STUDY OBJECTIVE

To measure the prevalence of allergic rhinitis, atopy, and asthma among grape farmers, and to compare the respiratory and atopic status in grape farmers with those of nonexposed control subjects.

DESIGN

Cross-sectional study.

SETTING

Malevisi region in northern Crete, Greece.

SUBJECTS AND METHODS

One hundred twenty grape farmers and 100 control subjects living in the Malevisi region were examined. The protocol comprised a questionnaire, skin prick tests for 16 common allergens, measurement of specific IgE antibodies against 8 allergens, and spirometry before and after bronchodilation.

RESULTS

Grape farmers were found to have an excess of respiratory symptoms. The comparison with the control group, after adjusting for age, sex, and smoking status, showed that the differences were statistically significant for rhinorrhea (odds ratio [OR], 2.7; 95% confidence interval [CI], 1.5 to 5.1; p < 0.001), sneezing (OR, 2.2; 95% CI, 1.2 to 4.0; p < 0.01), and nasal itching (OR, 1.9; 95% CI, 1.0 to 3.6; p < 0.05), but were nonsignificant for asthma-related symptoms. In the multiple logistic regression model, grape farmers were found to have increased work-related symptoms, such as sneezing (OR, 2.9; 95% CI, 1.3 to 6.6; p < 01), rhinorrhea (OR, 2.9; 95% CI, 1.3 to 6.6; p < 0.01), cough (OR, 3.7; 95% CI, 1.2 to 11.4; p < 0.05), and dyspnea (OR, 3.8; 95% CI, 1.1 to 1.3; p < 0.05). The prevalence of allergic rhinitis was 40.8% in grape farmers and 26% in control subjects (OR, 2.0; 95% CI, 1.1 to 3.5; p < 0.02). Increased but statistically nonsignificant values of asthma prevalence were found in grape farmers (6.7%) compared with the control group (2.0%). The prevalence of atopy was 64.2% in grape farmers and 38.0% in the control group (OR, 2.2; 95% CI, 1.2 to 3.5; p < 0.01). Mean FEV1 was significantly lower in grape farmers than in control subjects (p < 0.05), after adjusting for age, sex, and smoking status. Bronchial obstruction was reversible in 23 grape farmers (19.2%) and in 6 control subjects (6%; p < 0.01).

CONCLUSIONS

The study mainly demonstrated the high prevalence of allergic rhinitis and work-related respiratory symptoms in grape farmers compared to control subjects. It also suggested that grape farming is possibly associated with increased allergic sensitization to specific pollens, low baseline FEV1, and increased bronchial hyper-responsiveness. Further studies are needed to determine the potential risk factors for these disorders among the farming population.

Prevalence and predictors of respiratory symptoms among New York farmers and farm residents

BACKGROUND

Data from telephone interviews with New York farmers and farm residents were used to study the prevalence and risk factors of symptoms that could be related to asthma and allergies.

METHODS

Participants were asked if they had wheezing or whistling in the chest in the past year and about the occurrence of stuffy, itchy, runny nose or watery, itchy eyes in the past year.

RESULTS

The prevalence of wheeze was 18.2% and of stuffy nose/watery eyes was 57.4% (N = 1,620). Significant risk factors for wheeze were cigarette smoking, a systemic reaction to allergy skin testing, immunotherapy, or insect sting, reactivity to a pet, having goats, and more acreage in corn for silage. Significant risk factors of stuffy nose/watery eyes were younger age, having more than a high school education, being a worker on the farm, and having done spraying.

CONCLUSIONS

Wheeze may be indicative of existing or latent asthma, a potentially limiting respiratory illness. Stuffy, itchy, runny nose or watery, itchy eyes, which may cause irritation and discomfort, may also indicate an increased sensitivity to respirable dusts and chemicals. This cohort of New York farmers had significant farm-related risk factors for wheeze and stuffy nose/watery eyes.

Evaluation of a respiratory health program for farmers and their families

Occupational exposures to organic dusts, gases, welding fumes and agricultural chemicals result in farmers' increased risk of respiratory health problems compared to other workers. The Respiratory Health Program for Saskatchewan farmers addresses the difficulties of delivering an occupational health program to a sparsely distributed population on the Prairies. We summarized their pulmonary function and respiratory health by spirometry and questionnaire respectively. The necessity of the program was demonstrated by the frequency of lower than predicted pulmonary function tests and referrals to family physicians (1996 through 1999). Age, years in farming, usual cough, wheezing on most days and nights, bringing up phlegm from the chest, breathlessness, and cigarette smoking were associated significantly with pulmonary function results. We evaluated the Respiratory Health Program (1994 through 2000) with respect to acceptability, accessibility, appropriateness, continuity, effectiveness, efficiency, and risk/safety by using questionnaires and evaluations by farm families.

Respiratory findings in farmworkers

This investigation was designed to study respiratory problems in farmworkers. To better define the consequences of this work environment on respiratory health, 814 farmworkers (738 male and 76 female) were studied. The mean age of the men in this study was 38 years, and the mean duration of their employment was 15 years. For women, the mean age was 44 years and the mean duration of their employment was 10 years. Of the men, 56.5% were regular smokers, and 23.7% of the women were regular smokers. A group of 635 control workers without significant exposure to air pollutants were matched by sex, age, employment, and smoking habit. The prevalence of chronic symptoms among male farmworkers was greater (P < 0.01) than among male control subjects for chronic cough (24.8% vs 11.4%), chronic phlegm (22.8% vs 9.1%), and chronic bronchitis (20.1% vs 7.4%). Among women farmworkers, a significant difference was noted with controls for chest tightness (farmworkers, 21.1%; control subjects, 0%; P < 0.001). There was a high prevalence of acute symptoms among male and female farmworkers. In particular, farmworkers complained of more frequent cough, eye irritation, dyspnea, and throat irritation than did control subjects. For respiratory symptoms in male and female farmworkers, odds ratios were generally significant for smoking, age, and duration of employment. Ventilatory capacity tests were significantly reduced for farmworkers compared with predicted values. Regression analysis of ventilatory capacity tests in male farmworkers as a percentage of predicted values demonstrated significant coefficients for employment and smoking. Our data suggest that farmworkers are exposed to noxious agents that cause respiratory symptoms and ventilatory capacity impairment.

Work-related respiratory symptoms in New Zealand farmers

BACKGROUND

The first national survey of the respiratory health of New Zealand farmers looked at the prevalence of respiratory symptoms by farm type and work exposure.

METHODS

An 8-page questionnaire was mailed to 2,203 farmers randomly selected from all over New Zealand.

RESULTS

Response rate was 77.6% of 2,203, or 1,706 participants. Breathing problems at work were reported by 17.6% of farmers. Working with oats was strongly associated with work-related breathing problems (OR = 3.3, 2.1-5.2). Dyspnea was more common in female farmers, whereas chronic bronchitis was higher in males. Orchardists (OR = 2.3, 1.3-4.0), those growing oat crops (OR = 3.0, 1.7-5.4) and using the grain mill (OR = 2.8, 1.3-6.3) reported the highest symptom rates of ODTS/FL. Having hay fever or eczema, and smoking were risk factors for all respiratory symptoms.

CONCLUSIONS

Working in the areas of pigs, poultry, horses, grains, and hay are associated with respiratory symptoms in New Zealand farmers.

[Prevalence and risk factors of respiratory symptoms in farmers; comment]

BACKGROUND

A cross-sectional study was performed to determine the prevalence of respiratory symptoms in farmers and to assess occupational risk factors for respiratory symptoms in this population.

METHOD

A questionnaire on respiratory symptoms and occupation was mailed to a sample of 1,191 farmers with descriptive analysis of the symptoms and multivariate analysis through logistic modeling to assess the different risk factors.

RESULTS

1,164 workers answered the questionnaire (response index 98.2%) and 808 subjects were finally included in the study after discarding non exposed workers. The highest prevalences of asthma symptoms (39.2%) and symptoms of nasal allergy (31.6%) were found in poultry workers (p < 0.001, chi square). Sheep workers showed the highest prevalences of chronic phlegm (38.5%), work-related symptoms (53.9%) and symptoms of organic dust toxic syndrome (35.9%) (p < 0.005, chi square). At multivariate analysis, adjusting for age, gender, smoking and other occupational exposures, poultry work was a risk factor for asthma symptoms (OR 2.1; IC 95% 1.2-3.8) and symptoms of nasal allergy (OR 2.3, IC 95% 1.3-4.2), and dairy farming a risk factor for chronic phlegm (OR 1.8, IC 95% 1.1-2.9). Agriculture was not associated with respiratory symptoms.

CONCLUSION

In our study risk factors for respiratory symptoms in Spanish farmers were poultry and dairy farming.

Distribution of dust-mite allergens (Lep d 2, Der p 1, Der f 1, Der 2) in pig-farming environments and sensitization of the respective farmers

BACKGROUND

The aim of the present study was to determine the distribution of mite allergens in pig-farming environments in comparison to urban homes and the relationship between exposure to mite allergens and sensitization to the respective allergens in 100 pig farmers with work-related respiratory symptoms.

METHODS

The concentration of storage mite (Lep d 2) and house-dust-mite (Der p 1, Der f 1, and Der 2) allergens in dust collected from five different sampling sites (floor, wall, grain mill, transit area between confinement house and farmer's kitchen, and farmers' mattresses) was studied in relationship to the respective sensitization rates. Allergen concentrations in the mattresses were compared to those determined in mattresses from 22 urban dwellers.

RESULTS

Median concentrations of Der p 1 and Der 2 in the mattresses of the farmers were significantly higher than in the urban dwellers' samples (53.4 microg/g dust vs 1.05 microg/g dust, P=0.001; 19.6 microg/g dust vs 2.2 microg/g dust, P<0.0001, respectively). Allergen concentrations in the transit areas were strongly related to bedroom exposure. In a multiple logistic regression model, a weak but significant relationship between Der p 1 exposure and sensitization to Der p 1 was found. Despite these findings, the prevalence of sensitization to mite allergens in the farmers (18%) was comparable to the prevalence in the general population.

CONCLUSIONS

Allergen exposure at the workplace is strongly related to the concentration of allergens in farmers' beds. Exposure to domestic mite allergens should be taken into account when assessing occupational exposure to allergens and the respiratory health of farmers.

Asthma and allergy in New Zealand farmers

AIMS

To examine the prevalence of symptoms of asthma and allergy in different farming groups in New Zealand.

METHODS

A postal questionnaire was sent to a random sample of 2,500 farmers throughout New Zealand.

RESULTS

The response rate was 77% (1,706 of 2,203 eligibles). The 12-month period prevalence of current asthma was 11.8% overall, compared with 15% in the general population. Asthma prevalence was higher for horse breeders/groomers (16.5%), pig farmers (18.2%), poultry farmers (17.4%), and those working with oats (17.4%). Asthma was also significantly elevated among those working with cleaning powders (14.7%). Women were more likely to report current asthma than were men (OR 1.8, 95% CI 1.3-2.5). Hay fever was significantly higher in deer and crop farmers, and farmers working with horses and goats; eczema was higher for goat and deer farmers.

CONCLUSIONS

The lower overall prevalence of asthma in farmers may be due to the healthy worker effect. Among farmers, the types of farming associated with an elevated prevalence of asthma and allergy in New Zealand are deer and goat farming, working with horses, poultry, pigs, and crop farming. Females reported more current asthma than males.

Increasing prevalence of asthma over 12 years among dairy farmers on Gotland, Sweden: storage mites remain dominant allergens

BACKGROUND

Earlier studies from several countries have shown that IgE-mediated allergy in rural populations is of considerable importance and that storage mites are dominant allergens.

OBJECTIVE

In an epidemiological follow-up study among farmers on the island of Gotland, Sweden in 1996 we wished to investigate the prevalence of respiratory allergy and to find out whether storage mites are still important allergens in a farming environment.

METHODS

A questionnaire concerning airway symptoms, social and working conditions and smoking habits was distributed to all Gotland farmers aged 15-65 years and was completed by 1577 (86.7%), of whom 1015 were dairy farmers. Based on the answers, 500 dairy farmers were invited to undergo a medical examination which included a skin-prick test (SPT) and blood sampling for RAST analyses. Prevalence figures (symptoms, RAST and SPT) given for the whole population (n = 1015) were based on the investigation of the 461 farmers who took part in the examination.

RESULTS

Immediate onset hypersensitivity was present in 41.7% of the 1015 farmers studied, which is almost the same figure as in 1984 (40.0%). The prevalence of asthma had increased significantly during the previous 12 years (5.3% vs 9.8%), as had asthma in combination with rhinoconjunctivitis (3.7% vs 7.0%). Rhinoconjunctivitis, on the other hand, had not changed significantly (36.5% vs 33.1%) and remained one of the most common symptoms. The prevalence of storage mite allergy in the farming population in 1996 was 6.5% and constituted an important cause of allergic symptoms.

CONCLUSION

Over 12 years, Gotland dairy farmers have developed significantly more respiratory symptoms from the lower airways, although the proportion with atopy is unchanged. Storage mites are still dominant allergens for developing allergic disease.

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.

Current issues in the management of chronic obstructive pulmonary diseases

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality, especially among smokers. Many guidelines that have recently been issued emphasize that COPD is not inaccessible to therapeutic measures: although few interventions are capable of affecting its natural history (i.e. smoking cessation and, in patients with severe resting hypoxaemia, oxygen therapy), several others have a demonstrated effect on symptoms and, thereby, quality of life. The effects of inhaled corticosteroids, and alpha 1-antitrypsin replacement therapy in emphysema due to alpha 1-antitrypsin deficiency are currently being studied. When there is a marked increase in mucus production, chest physiotherapy using controlled expiration and directed cough may be useful. Inhaled bronchodilators are frequently effective on dyspnoea, anticholinergic agents being more suitable for continuous symptoms. Rehabilitation, which includes education and psychosocial care, chest physiotherapy, nutritional care and exercise training, also improves quality of life. When there is persistent severe alveolar hypoventilation despite oxygen therapy, long-term mechanical ventilation may be considered. Surgical options in the treatment of emphysema include resection of giant bullae and lung volume reduction surgery. Lung transplantation should be proposed only in patients with end-stage disease, the difficulty here being to define what 'end-stage' means. Finally, all preventive and some therapeutic interventions are likely to be more effective early in the course of the disease. Thus, efforts should be made to detect airways obstruction early in subjects at risk, such as smokers.