High risk of adult-onset asthma and work-related wheeze in farmers despite low prevalence of asthma in young farmers.

OBJECTIVE: To investigate risk factors for asthma in farmers. METHODS: A questionnaire was sent to all farms (n = 2499) and to 2900 controls aged 19-65 years from the general population in the county of Uppsala. Sixty per cent of the farms (1514 men and 248 women) and 64% of the controls (900 men, 943 women) responded. RESULTS: Only 13% of the male farmers had heredity for allergy compared to 24% of the controls, and fewer farmers were smokers. After adjusting for confounders, male farmers had a significantly lower prevalence of doctor-diagnosed asthma and nocturnal breathlessness than the controls (OR 0.75, 95%CI 0.57-0.98 and OR 0.61, 95%CI 0.44-0.84), but a significantly higher prevalence of work-related wheeze (OR 1.74, 95%CI 1.30-2.35). The risk for asthma increased with age in the farmers. Of male farmers with asthma, 70% had developed asthma after the age of 21, in contrast with only 30% of the asthmatic controls. The young female farmers had a high prevalence of asthma. CONCLUSION: Male farmers have an increased risk of work-related wheeze and adult-onset asthma increasing with age despite a lower prevalence of asthma during childhood and young age than in the general population.

Tractor-driving hours and their relation to self-reported low-back and hip symptoms.

Tractor driving might be one causal risk factor in the incidence of low-back and hip symptoms among farmers. Information on the annual exposure to tractor driving and its distribution among different work operations is scarce. The purpose of this study was to quantify the total and the annual time driving tractors among Swedish farmers and its distribution into different work operations, and to investigate the risk of low-back and hip symptoms in relation to tractor driving within different work operations. The data were collected from a questionnaire study sent to all farms with acreage more than 10 ha in a county in Sweden. Farmers having farming and/or forestry as their main occupation in 1995 were included in the analysis. The annual tractor-driving time and the percentage distribution within different work operations were calculated for females, males, the total group and four production groups. The risk calculations for low-back and hip symptoms from the variables related to tractor driving were performed on the total group. The results showed that the mean annual tractor-driving time was 472 h. Ploughing was the single most time-consuming work operation but it had no influence on the risk for low-back or hip pain. The results showed that some of the variables investigated related to tractor driving influenced the risk for low-back and hip symptoms.

Asthma, skin symptoms, and allergy in a condom factory.

BACKGROUND: Cases of occupational asthma have been reported in condom factories in the UK and France, but there has been no epidemiologic study of groups of workers in such factories. This investigation aimed to study the prevalence of symptoms in a Swedish condom factory, to determine groups at special risk, and to suggest preventive measures. METHODS: A questionnaire was mailed to 35 employees, 29 women and six men with mean ages of 37 and 32 years, respectively. All subjects were interviewed by a physician and underwent skin prick test with latex and epicutaneous testing with 39 substances, and blood samples were taken for allergy testing. RESULTS: Phadiatop was positive in 23%, RAST against Lycopodium in 31%, and RAST against latex in one of these 11. Ten subjects (29%) had work-related nose/eye symptoms; of these, eight had positive RAST to Lycopodium; three also had symptoms of occupational asthma and contact urticaria. Only one had positive RAST to latex. Five of the nine subjects with positive Phadiatop also had positive RAST to Lycopodium. All those with RAST positive to Lycopodium had worked in packaging, the area of the factory with the greatest exposure. The results of the patch tests did not correlate with the work-related symptoms. CONCLUSIONS: In a Swedish condom factory, there were a high prevalence of rhinoconjunctivitis and a small number of cases of asthma and contact urticaria caused by allergy to Lycopodium.

Occupational exposures, animal exposure and smoking as risk factors for hairy cell leukaemia evaluated in a case-control study.

To evaluate occupational exposures as risk factors for hairy cell leukaemia (HCL), a population-based case-control study on 121 male HCL patients and 484 controls matched for age and sex was conducted. Elevated odds ratio (OR) was found for exposure to farm animals in general: OR 2.0, 95% confidence interval (CI) 1.2-3.2. The ORs were elevated for exposure to cattle, horse, hog, poultry and sheep. Exposure to herbicides (OR 2.9, CI 1.4-5.9), insecticides (OR 2.0, CI 1.1-3.5), fungicides (OR 3.8, CI 1.4-9.9) and impregnating agents (OR 2.4, CI 1.3-4.6) also showed increased risk. Certain findings suggested that recall bias may have affected the results for farm animals, herbicides and insecticides. Exposure to organic solvents yielded elevated risk (OR 1.5, CI 0.99-2.3), as did exposure to exhaust fumes (OR 2.1, CI 1.3-3.3). In an additional multivariate model, the ORs remained elevated for all these exposures with the exception of insecticides. We found a reduced risk for smokers with OR 0.6 (CI 0.4-1.1) because of an effect among non-farmers.

Pleural disease during treatment with bromocriptine in patients previously exposed to asbestos.

Bromocriptine, which is used in the treatment of Parkinson's disease, can cause adverse pleuropulmonary reactions. Exposure to asbestos can result in similar lesions. Fifteen patients with former exposure to asbestos, who developed pleural fibrosis after treatment with bromocriptine, were observed independently in Sweden (11 patients) and Australia (four patients). The patients complained of malaise, often associated with weight loss, dyspnoea, and a disturbing cough. Laboratory values included increased erythrocyte sedimentation rate and a low haemoglobin level. Lung function tests showed a restrictive lung function defect. Chest radiographs showed bilateral pleural fibrosis, with small amounts of fluid in some cases. Soon after bromocriptine was withdrawn, the patients improved clinically, and the laboratory values returned to normal. However, in most cases, pleural fibrosis and a restrictive lung function defect persisted to some extent. In conclusion, in patients who develop pleuropulmonary fibrosis whilst being treated with bromocriptine, former exposure to asbestos should be investigated. Conversely, when pleural changes develop in a patient on bromocriptine and with prior exposure to asbestos, the possible causative role of the drug should be discussed. Special follow-up may be indicated when bromocriptine is planned in a patient with previous asbestos exposure, and if symptoms or signs of pleural fibrosis develop, bromocriptine withdrawal should be considered.

Occupation and occupational exposure to UV light as risk factors for hairy cell leukaemia evaluated in a case-control study.

To investigate the role of occupation as a risk factor for hairy cell leukaemia a case-control study on 121 male, hairy cell leukaemia (HCL) patients, and 484 controls matched for age and sex, was conducted. We found significantly elevated risk for HCL among building painters (OR, 5.7; 95% CI, 1.6-20.8; based on six cases and four controls) and construction workers (OR, 3.3; CI, 1.2-9.2; based on seven cases and eight controls). Farming has been suggested as a risk factor in HCL. In this investigation farmers had an OR of 1.2 (CI, 0.6-2.3) and farm workers an OR of 1.5 (CI, 0.8-2.8). However, having ever worked in farming yielded an OR of 1.8 (CI, 1.1-2.9). Having grown up mainly in a rural area gave an OR of 1.4 (CI, 0.9-2.4). UV light has been suggested as a risk factor for non-Hodgkin's lymphoma (NHL). To evaluate the impact of UV exposure, classification of occupations as indoor, outdoor or mixed indoor/outdoor was made. Outdoor and mixed outdoor/indoor work yielded ORs of 2.3 (1.0-4.9) and 1.6 (1.0-2.5), respectively. When the effect of outdoor/indoor or mixed indoor/outdoor work was analysed using a scoring system the OR was 2.0 (CI, 0.9-4.4) for farmers compared with 0.8 (CI, 0.3-1.9) among non-farmers in the highest scoring group. There was no clear correlation between socioeconomic status as defined by the Swedish Socio-Economic Classification (SEI), and the risk of HCL. As many comparisons were made, the possibility of associations occurring by chance can not be excluded.

Increased bronchial responsiveness in workers sawing Scots pine.

The purpose of the present investigation was to study bronchial responsiveness and pulmonary function in Swedish sawmill workers, who are not exposed to plicatic acid, the sensitizer in red wood cedar asthma. Bronchial responsiveness, transfer factor, spirometry, and precipitating antibodies in serum against sawmill fungi were measured in 164 workers at five sawmills. The results from workers inside the sawing area (sawyers, n=59), in the trimming department (trimmers, n=66), and from other workers in the sawmill (sawyer-referents, n=39) were compared. Sawyers had higher bronchial responsiveness than referents. In 55% of the sawyers FEV1 decreased by 20% or more within the highest dose of methacholine compared with 31% of sawyer-referents and 41% of trimmers (p<0.01, sawyers/referents). Sawyers decreased 74% more in FEV1 per milligram of inhaled methacholine compared with referents (geometric means, p<0.01). The transfer test in never-smokers was 13% lower in sawyers than in trimmers (p<0.01) and 8% lower compared with sawyer-referents (nonsignificant p<0.1). Presence of precipitating antibodies was not associated with changes in pulmonary function. Some agents in the sawing area of sawmills appear to increase bronchial responsiveness and decrease diffusion capacity.

Is hairy-cell leukemia more common among farmers - a pilot-study.

Hairy cell leukaemia (HCL) is a rare non-Hodgkin lymphoma of unknown aetiology most frequently diagnosed in males. In earlier epidemiological studies of HCL, exposures to benzene and chemicals appear to be risk factors. Since 1984, 48 patients (36 men and 12 women) with HCL has been treated in Uppsala. Information on occupation was collected from the medical records. 29 percent (13 men and one woman) worked in farming. One additional man worked in gardening. Of the men, 39 percent had this kind of work giving an OR of 7.5 (CI. 4.2-13.2) compared with the general Swedish population in 1970. A larger case control study is now being conducted.

Inhalation fever and respiratory symptoms in the trimming department of Swedish sawmills.

Mold dust exposure in the trimming departments of sawmills may cause inhalation fever as well as allergic alveolitis. Responses to questionnaires sent to 2,052 workers from trimming departments of 233 Swedish sawmills showed that one of five workers experienced work-related febrile attacks. A single case of allergic alveolitis was found.

Exposure to microorganisms associated with allergic alveolitis and febrile reactions to mold dust in farmers.

STUDY OBJECTIVE: To compare exposure to microorganisms associated with allergic alveolitis (AA) and with febrile reactions to inhaled mold dust (organic dust toxic syndrome [ODTS]) in farmers and in normal subjects. DESIGN: A prospective study in which exposure was evaluated within two weeks of medical consultation for AA or ODTS. Samples were collected during normal farming (background) and during the handling of materials associated with disease or causing maximal exposure in reference farms (worst case). SETTING: Swedish farms PARTICIPANTS: Eleven farmers with a confirmed diagnosis of AA from ten farms, 16 subjects with symptoms of ODTS from 12 farms, and 17 reference farmers. MEASUREMENTS AND RESULTS: Worst-case samples representative of the exposure preceding disease were obtained on four farms where five farmers had had AA; the samples contained on average 2.6 +/- 1.8 x 10(9) (SD) spores/m3 of air. On six farms where nine farmers had had ODTS, representative samples averaged 13 +/- 13 x 10(9) spores/m3, and on reference farms this figure was 0.12 +/- 0.20 x 10(9) spores/m3. The daily spore dose associated with allergic alveolitis was 2 x 10(9) spores/d, which was ten times higher than on reference farms. The average dose associated with ODTS was 2 x 10(10) spores. Worst-case samples, collected during 10 to 30 min, contributed to more than 90 percent of the day exposure on farms where AA or ODTS had occurred. CONCLUSION: Allergic alveolitis was associated with high exposure levels on most weekdays for weeks, and ODTS was associated with extreme exposure occurring on a single day. There was no correlation with individual spore types and disease and the present results are compatible with a hypothesis that common cell wall components of microorganisms may cause "toxic" symptoms and stimulate immune reactions.

Endotoxin levels in farming: absence of symptoms despite high exposure levels.

The endotoxin concentration in air was measured in farms where 11 farmers had experienced febrile reactions or allergic alveolitis and in a random sample of farms with 17 symptomless farmers. Samples were obtained during normal dairy farming in eight reference farms (background samples) and in all farms during the handling of material which had probably caused symptoms or disease or, in reference farms, maximal spore exposure (worst case samples). In addition, parallel samplers were used in reference farms, one with a cyclone (5 microns cutoff) and one without, to measure the dust and endotoxin concentrations in the respirable fraction and total dust. The endotoxin worst case values varied from less than 0.01 to greater than 50 micrograms/m3 in symptom farms (median 6.4 micrograms/m3, geometric mean 2.2 micrograms/m3) and from less than 0.01 to greater than 50 micrograms/m3 in reference farms (median 42 micrograms/m3, geometric mean 29 micrograms/m3). This difference was not statistically significant. The background values in reference farms were 1.3 (median) and 0.4 (geometric mean) micrograms/m3. The differences between samples with and without cyclone and between background and worst case samples were statistically significant (p less than 0.02). About 75% of the activity was found in the non-respirable fraction. No correlation was found between exposure to endotoxin and symptoms in farmers. There were weak, but statistically significant, correlations between endotoxin concentrations and total spore count or dust concentrations. The surprisingly high endotoxin values in the respirable fraction of air from environments which apparently did not cause symptoms raises the concern that the Limulus amebocyte assay might be sensitive to other components in the dust rather than endotoxin.

Organic dust toxic syndrome among farmers.

Clinical symptoms and exposure conditions were investigated in 80 farmers with organic dust toxic syndrome, defined as the occurrence of febrile reactions after exposure to organic dust in subjects with no evidence of allergic alveolitis. The material was compiled from a field study of febrile reactions in the farming community and the diagnosis was based on interviews performed by physicians. Of the 75 men (mean age 44) and five women (mean age 39), only 13% of the men and none of the women were current smokers. One attack had been experienced by 44% and the remaining subjects had had two or more attacks, often several years apart. The duration of symptoms was 24 hours or less in 46% of the farmers and in 95% of the cases the symptoms lasted less than one week. The attacks were most common in the autumn and were usually provoked by handling grain (80% of the farmers with organic dust toxic syndrome). Other causes were hay, straw, wood chips, and silocapping material. The material was usually described as extremely mouldy and the episodes were usually provoked by unusual work tasks such as cleaning grain bins or removing mouldy feed. Twenty three farmers had consulted physicians: five of nine examined during symptoms had slightly abnormal chest radiographs and two of four examined had decreased arterial oxygen tension. Spirometry performed during a symptom free interval was normal.

Allergic alveolitis in Swedish farmers.

Allergic alveolitis due to mold dust inhalation in farmers is a severe but rare disease in Scandinavia. In this report 38 cases of the disease are presented. There were 31 men and 7 women, with mean ages of 46 and 38 years respectively. Strict diagnostic criteria were used, resulting in 21 definite, 12 probable and 5 possible cases. None of the patients were current smokers, but 10 of the men were ex-smokers. The great majority of the patients fell ill between October and April. The symptoms were dyspnea, cough, fatigue, episodes of fever, and in some cases loss of weight. The average duration of the disease was 6 months. The moldy material most commonly associated with the disease was straw, followed by hay, grain, and wood chips. For those tested serum lactate dehydrogenase was raised in 80% and the mean value for PaO2 was 7.8 kPa. Precipitating antibodies to mold antigens were positive in 68%. In general, pulmonary function tests showed a restrictive pattern. Over half of the patients still had dyspnea on exercise after recovery. Three fourths of the patients were treated with antibiotics and thus clearly had been misjudged as having an infection.