[Defending confidence intervals].
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Biomedical subjects
Publications and source records attributed to Ralph Nilsson.
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BACKGROUND: Whether new-onset asthma is associated with irritant exposure is unclear. The aim was to investigate if occupational exposure to irritant gases, especially repeated peak exposure (gassings), increased the risk of obstructive airways disease. METHODS: Data on airway symptoms and exposure among bleachery (n = 101) and paper department workers (n = 314) were collected by a questionnaire. Incidence rates and hazard ratios (HR) (Cox regression) were calculated. Non-responders were interviewed by telephone. RESULTS: The incidence rate for adult-onset physician-diagnosed asthma among bleachery workers reporting gassings giving rise to respiratory symptoms was 7.6/10(3) person-years and for those without gassings 2.2/10(3) person-years, compared to 1.0/10(3) person-years for paper workers. In a Cox regression model for asthma (n = 12), stratified for sex, HR for gassings were 5.6 (95% confidence intervals (CI) 1.6-20), for hay fever 3.0 (95% CI 0.8-11), and for ever smoking 0.7 (95% CI 0.2-2.4). The same model for adult-onset wheeze gave HR of 5.2 (95% CI 2.2-12), 1.7 (95% CI 0.6-5.4), and 1.1 (95% CI 0.5-2.7), respectively. CONCLUSIONS: Repeated peak exposure to irritant gases, here studied as gassings in the pulp industry, increased the risk for both adult-onset asthma and wheeze.
BACKGROUND: The incidence of testicular cancer has increased in recent decades. The aims of the present study were to elucidate whether Swedish paper and pulp mill workers had an increased incidence of testicular cancer, and to investigate whether certain occupational groups within the pulp and paper mill workforce were at increased risk. METHODS: The study was based on the Swedish Cancer Environment Register, which links the incidence of cancer for the period 1971-1990 with 1960 and 1970 National Census data on specific industries and occupations for all employed subjects in Sweden. RESULTS: Among maintenance workers employed both in 1960 and in 1970 in paper mills there was an increased risk for testicular cancer (standardized incidence ratio (SIR) 7.4, 95% confidence intervals (CI) 1.5-22), especially for seminomas (SIR 10.1, 95% CI 2.1-29). Maintenance workers were also at increased risk when analyzing workers employed in 1960, 1970, or both years. CONCLUSIONS: This study indicates an increased risk for testicular cancer, especially seminomas, among maintenance workers, but not among process workers, in Swedish paper mills.
OBJECTIVES: This study investigated whether previous findings of an increased risk of gliomas among workers in some pulp and paper mills could be confirmed for all Swedish pulp and paper mill workers and whether the increase could be attributed to certain occupational groups. METHODS: The study was based on the Swedish Cancer Environment Register, which links the incidence of cancer from 1971 to 1990 and the 1960 and 1970 census data on codes of occupation and industry for the whole population. Standardized incidence ratios (SIR) were used to estimate the risks for men in different occupations in pulp (N = 28,142) and paper (N = 39,169) mills in 1960, 1970 or both years as compared with those of all gainfully employed men in Sweden. RESULTS: Maintenance workers employed in pulp or paper mills in 1960, 1970 or both years, as well aspulp workers, showed an increased incidence of gliomas in 1971-1990 [SIR 1.5, 95% confidence interval (95% CI) 1.1-2.1 and SIR 1.5,95% CI 1.0-2.2, respectively], whereas the incidence among process workers in paper mills was lower than expected (SIR 0.6, 95% CI 0.3-0.9). Taken together, all employed men in the pulp mill industry had an increased incidence of gliomas (SIR 1.3, 95% CI 1.0-1.7). CONCLUSIONS: Pulp mill workers, but not paper mill workers, were found to have more gliomas in 1971-1990 than expected. There was an increased risk of gliomas among maintenance workers in both pulp and paper mills. Few risk factors for brain tumors are recognized, and the causes of the increase are not obvious.