OBJECTIVES: This study examined certain occupational exposures and the risk for adult-onset asthma. METHODS: A nested case-referent study of adult-onset asthma was performed on a random population sample (N=15813), aged 21 to 51 years. Cases for the study included 2 groups: subjects reporting "physician-diagnosed" asthma (N=251) and a broader "asthma" group (N=362). The "asthma" group consisted of subjects with "physician-diagnosed" asthma (N=251) and subjects reporting asthma-like symptoms without having "physician-diagnosed" asthma (N=111). The referents (N=2044) were randomly selected from the whole population sample. The case-referent sample was investigated with a comprehensive questionnaire about occupational exposures, asthma, respiratory symptoms, smoking, and atopy. Odds ratios were calculated with stratification for gender, year of diagnosis, and birth year. RESULTS: The highest odds ratio for "physician-diagnosed" asthma was associated with exposure to flour dust [odds ratio (OR) 2.8, 95% confidence interval (95% CI) 1.5-5.2] and the occupational handling of resin-based paints (isocyanates) (OR 3.0, 95% CI 1.6-5.9). Exposure to welding fumes, textile dust, and work with glues containing acrylates was also associated with an increased odds ratio for "physician-diagnosed" asthma. Including persons with asthma-like symptoms (ie, the asthma group) showed similar results. CONCLUSION: This population-based case-referent study from Sweden indicates that occupational exposure to acrylate-based compounds and welding fumes is associated with increased risk for adult-onset asthma.
While the increased risk of lung cancer and mesothelioma is well established, the relationship between exposure to asbestos dust and sinonasal cancer is less clear.
To study the risk of sinonasal cancer in relation to asbestos dust exposure.
A retrospective cohort study of construction workers, linked to the Swedish Cancer Registry. Participants were classified into four exposure groups; heavy, medium, low or very low exposure to asbestos, according to the incidence of pleural mesothelioma in their occupational group. Standardized incidence ratios (SIRs) and relative risks (RRs) were analysed, adjusted for age and smoking habits. The risks of adenocarcinoma and squamous cell carcinoma were investigated separately.
Among the 280222 subjects, there was no increased risk of sinonasal cancer compared to the general population [SIR 0.85, 95% confidence interval (CI) 0.68-1.03], or any dose-response relationship with exposure to asbestos. The highest RR was found in the low exposure group (RR 1.25, 95% CI 0.69-2.28) and the lowest RR was found in the group with the highest exposure to asbestos (RR 0.71, 95% CI 0.33-1.53). No significantly increased risk or dose-response association could be found for adenocarcinoma or squamous cell carcinoma when analysed separately.
This study did not find an increased risk of developing sinonasal cancer after asbestos exposure.
BACKGROUND: Atopic sensitization is a well-known risk factor for asthma and bronchial hyperresponsiveness (BHR). Mites have been regarded as the most important allergens, but the prevalence of sensitization to mites is relatively low in Sweden. OBJECTIVE: The aim of the study was to investigate possible associations between sensitization to various allergens and asthma and BHR in adults. METHODS: A random sample of 1859 subjects, aged 20 to 46 years, was investigated in a cross-sectional study by using a questionnaire, skin prick tests (SPTs), specific and total IgE measurements, and methacholine bronchial challenge tests. Possible associations were analyzed univariately and by using multivariate logistic regression analysis and proportional hazard regression analysis. RESULTS: Positive SPT and specific IgE results were more common in subjects with asthma and BHR than in subjects without these conditions for all allergens. The independent associations between positive SPT responses and asthma and BHR are given as adjusted prevalence ratios (PRRs): pets and asthma, PRR = 3.6; pets and BHR, PRR = 2.0; grass and asthma, PRR = 2.0; grass and BHR, PRR = 1.7; mites and asthma, PRR = 1.4; and mites and BHR, PRR = 1.2. The use of specific IgE measurements instead of SPTs showed essentially similar results. CONCLUSION: Cats and dogs were the sensitizing allergens most closely associated with asthma and BHR. The relationships with sensitization to grass and mites were less pronounced.
SETTING: The prevalence of asthma is useful for studying the causes of asthma. OBJECTIVE: To ascertain whether there is a relationship between the prevalence and incidence of asthma. DESIGN: The association between age and the occurrence of asthma was analysed in an epidemiological study of 15,813 persons. RESULTS: Different conclusions were reached depending on whether the point prevalence, cumulative prevalence or the incidence rates were studied. The relation between the incidence and prevalence of asthma is described in two epidemiological models, and none of the models seem to fit empirical data. Furthermore, it is shown that estimating incidence rates by prospectively measuring the point prevalences may introduce a considerable bias if the reliability of the diagnosis of asthma is around or below an agreement of 99%, which is probably usually the case. Including asthmatic symptoms during the last year in the definition of point prevalence means that there is no simple relation between incidence rates and point prevalences. CONCLUSION: The point prevalence may be a biased measure in the study of the etiology of asthma, as there is no simple relationship between the incidence and prevalence of asthma.
The aims of this study were to estimate the risk to bakers of developing hay fever and rhinitis, to assess the modifying effect of atopy and to estimate the occurrence of job change due to nasal symptoms. A retrospective cohort study was performed among bakers trained in Swedish trade schools from 1961 to 1989 (n=2,923). School control subjects (n=1,258) comprised students in other programmes in the trade schools and population controls (n=1,258) were randomly selected from the general population. A questionnaire on hay fever, rhinitis, the year of onset of these diseases, change of work due to nasal symptoms and work history was mailed to all participants. The atopic state of the responders was assessed by questions on allergic diseases in childhood and among next of kin. Incidence rates for hay fever and other rhinitis were calculated. The relative risk (RR) for hay fever when working as a baker compared with all control subjects combined was increased in males (RR=1.9, 95% confidence interval (CI) 1.2-2.9). The RR for rhinitis in male bakers compared with combined control subjects was 2.8 (95% CI 2.3-3.4) and for female bakers 2.0 (1.6-2.7). Of the bakers, 6.1% had changed job due to nasal symptoms, significantly more than the controls. A history of respiratory atopy increased the incidence rates of hay fever and rhinitis, with a synergistic effect between atopy and bakery work in males. In conclusion, Swedish bakers, mainly working in the 1970s and 1980s, had an approximately doubled risk of developing rhinitis. Male bakers also had an increased risk for hay fever. There was a synergistic effect of bakery work and atopy such as a family history of hay fever. Bakers also changed job due to nasal symptoms more often than control subjects.
OBJECTIVES: To estimate the risk of cancer due to occupational exposure to petroleum products in the Swedish transport and refinery industries. METHODS: In a retrospective cohort study the cancer incidence in 4128 men and 191 women, who had worked for at least one year in the petroleum industry, was compared with the incidence in the general population. The job titles and employment times for each person were found in personal files in the industries. The men had on average worked in jobs exposed to petroleum for 11.6 years at the end of the observation period. The cases of cancer were identified by record linkage with the Swedish cancer register. RESULTS: In total there were 146 cases of cancer v 157.6 expected (standardised mortality ratio (SMR) 0.93 90% confidence interval (90% CI) 0.80 to 1.1). Operators at refineries had an increased risk of leukaemia (6 cases v 1.7 expected, 90% CI of relative risk (RR) 1.5 to 7.0). Five of the six cases had started to work at the refineries in the 1950s or later. No other significantly increased risk of cancer was found. Distribution workers had a decreased incidence of lung cancer (no cases, 90% CI of RR 0 to 0.4). CONCLUSIONS: Operators at Swedish refineries had an increased risk of leukaemia. A possible cause is exposure to benzene. There was no increased risk of leukaemia in distribution workers. Distribution workers had a decreased risk of lung cancer.
The mortality pattern among 86 men was determined to investigate the possible hazards of polishing steel. The men had polished steel with polishing paste for at least five years. The polishing pastes had contained tallow, beeswax, carnauba wax, alundum, carborundum, ferric oxide, and chalk. A total of 18 men had died compared with 13.3 expected. Four had died of stomach cancer compared with 0.44 expected (p less than 0.005). The mortality for other causes of death was not increased. The study does not permit any definite conclusion but indicates a possible cancer hazard among polishers.