Occupational exposure to noise and dust in Swedish soft paper mills and mortality from ischemic heart disease and ischemic stroke: a cohort study.

OBJECTIVE: To elucidate whether occupational noise exposure increases the mortality from ischemic heart disease (IHD) and stroke, and if exposure to paper dust modified the risks. METHODS: We studied 6686 workers from soft paper mills, with occupational noise exposure, < 85 dBA, 85-90 dBA and > 90 dBA, and high (> 5 mg/m3) exposure to paper dust. Person-years 1960-2019 were stratified according to gender, age, and calendar-year. Expected numbers of deaths were calculated using the Swedish population as the reference and standardized mortality ratios (SMR) with 95% confidence intervals (95% CI) were assessed. RESULTS: SMR for IHD was 1.12 (95% CI 0.88-1.41) for noise < 85 dBA, 1.18 (95% CI 0.90-1.55) for 85-90 dBA, and 1.27 (95% CI 1.10-1.47) among workers exposed > 90 dBA. Joint exposure to high noise exposure and high exposure to paper dust resulted in slightly higher IHD mortality (SMR 1.39, 95% CI 1.15-1.67). SMR for ischemic stroke was 0.90 (95% CI 0.37-2.15) for noise < 85 dBA, 1.08 (95% CI 0.45-2.59) for 85-90 dBA, and 1.48 (95% CI 0.99-2.00) among workers exposed > 90 dBA. High noise exposure and high exposure to paper dust resulted in higher ischemic stroke mortality (SMR 1.83, 95% CI 1.12-2.98). CONCLUSION: Noise levels > 90 dBA was associated with increased IHD mortality. Combined exposures of noise and paper dust may further increase the risks. Our results do not provide support for a causal relationship for ischemic stroke. Residual confounding from smoking has to be considered. Workers need to be protected from occupational noise levels exceeding 90 dBA.

Cancer incidence among workers in soft paper mills: A cohort study.

OBJECTIVES: To elucidate whether occupational exposure to soft paper dust increases the incidence of cancer. METHODS: We studied 7988 workers in Swedish soft paper mills from 1960 to 2008, of whom 3233 (2 187 men and 1046 women) had more than 10 years of employment. They were divided into high exposure (>5 mg/m3 for >1 year) or lower exposure to soft paper dust based on a validated job-exposure matrix. They were followed from 1960 to 2019, and person-years at risk were stratified according to gender, age, and calendar-year. The expected numbers of incident tumors were calculated using the Swedish population as the reference, and standardized incidence ratios (SIR) with 95% confidence intervals (95% CI) were assessed. RESULTS: Among high-exposure workers with more than 10 years of employment, there was an increased incidence of colon cancer (SIR 1.66, 95% CI 1.20-2.31), small intestine cancer (SIR 3.27, 95% CI 1.36-7.86), and thyroid gland cancer (SIR 2.68, 95% CI 1.11-6.43), as well as lung cancer (SIR 1.56, 95% CI 1.12-2.19). Among the lower-exposed workers there was an increased incidence of connective tissue tumors (sarcomas) (SIR 2.26, 95% CI 1.13-4.51) and pleural mesothelioma (SIR 3.29, 95% CI 1.37-7.91). CONCLUSION: Workers in soft paper mills with high exposure to soft paper dust have an increased incidence of large and small intestine tumors. Whether the increased risk is caused by paper dust exposure or some unknown associated factors is unclear. The increased incidence of pleural mesothelioma is probably linked to asbestos exposure. The reason for increased incidence of sarcomas is unknown.

Cardiovascular mortality in a Swedish cohort of female industrial workers exposed to noise and shift work.

PURPOSE: The aim was to study mortality due to cardiovascular disease as well as total mortality, among female industrial workers, and the association to occupational noise and shift work. METHODS: Women from cohorts of soft tissue paper mills (N = 3013) and pulp and paper mills (N = 1483) were merged into one cohort. Job exposure matrices were developed and used for classification of shift work and noise exposure. Every year was classified as shift work excluding nights or shift work including nights. Noise was classified into seven 5 dB(A) bins from < 75 to ≥ 100 dB(A). Mortality from cardiovascular diseases and total mortality during 1956-2013 was calculated as a standardized mortality ratio (SMR) with 95% confidence interval (CI) using the female general population as a reference. RESULTS: Fatal myocardial infarctions (N = 144) were increased in the total cohort, SMR 1.20 (95% CI 1.01-1.41) but not total mortality. The SMR for myocardial infarction for women exposed to noise ≥ 90 dB(A) for > 10 years was 1.41 (95% CI 1.02-1.89) and for those exposed to night shifts > 10 years, 1.33 (95% CI 0.91-1.89). Shift workers without nights ≤ 65 years, with noise exposure ≥ 90 dB(A), had SMR 2.41 (95% CI 1.20-4.31) from myocardial infarction. There was no increased mortality from cerebrovascular disease. CONCLUSIONS: Female paper mill workers had an increased mortality from acute myocardial infarction, especially before retirement age, when exposed to noise ≥ 90 dB(A) and with long-time employment. Exposure to shift work and noise usually occurred concurrently.

Mortality from cardiovascular disease in a cohort of Swedish seafarers.

PURPOSE: The aim of this study was to investigate whether Swedish seafarers have increased mortality from cardiovascular disease compared with the general population. METHODS: Register-based longitudinal cohort study of 85,169 Swedish seafarers where all subjects with a minimum of 30 days service registered in the Seafarers' Register 1985-2013 were included. Mortality from coronary heart disease, cerebrovascular disease and total mortality for comparison were analysed by calculating standardised mortality ratios (SMRs), with 95% confidence intervals (CIs). Mortality was further analysed by gender, duty on board, type of vessel, and over time. RESULTS: There was no increase in either mortality from cardiovascular disease or total mortality for seafarers, who had worked solely on passenger ferries. Mortality from coronary heart disease and cerebrovascular disease was increased for male seafarers < 46 years old who had worked on different types of vessels, SMR 1.48 (95% CI 1.06-2.01) and SMR 1.93 (95% CI 1.16-3.02), respectively. Analysing the seafarers by duty showed significantly increased SMRs from coronary heart disease in males aged < 46 of the categories "deck crew" and "engine officer/crew (ever)". The total mortality for seafarers who had worked on different types of vessels was increased; males SMR 1.05 (95% CI 1.02-1.09) and females SMR 1.17 (95% CI 1.04-1.30), but decreased over time. CONCLUSIONS: No increased mortality on passenger ferries but younger male seafarers on different types of vessels had increased mortality from cardiovascular disease. Reduction of hazardous occupational exposures onboard is important, such as shift work, stress and noise.