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.

Different induction of microsomal carboxylesterases, palmitoyl-CoA hydrolase and acyl-L-carnitine hydrolase in rat liver after treatment with clofibrate.

The levels of hepatic carboxylesterases, including palmitoyl-CoA hydrolase and decanoyl-D,L-carnitine hydrolase, were studied in total homogenates and subcellular fractions prepared from the livers of male rats fed diets containing 0.3% clofibrate. The microsomal carboxylesterase as well as the fatty acyl-thioesterase are differently induced by clofibrate feeding. The specific activities of acetanilide carboxylesterase and decanoyl-D,L-carnitine hydrolase increased more than 3-fold in the microsomal fraction, compared to pellet-fed control animals. The microsomal activities of palmitoyl-CoA hydrolase and propanidid hydrolase were decreased by about 20 to 40% in clofibrate-treated rats. The specific clofibrate hydrolase activity remained unchanged after clofibrate administration, indicating that this microsomal carboxylesterase is not induced by its own substrate. The data suggest a different distribution of the differing carboxylesterase along the endoplasmic reticulum.