PT Journal AU Hamazaki, Y Morikawa, Y Nakamura, K Sakurai, M Miura, K Ishizaki, M Kido, T Naruse, Y Suwazono, Y Nakagawa, H TI The effects of sleep duration on the incidence of cardiovascular events among middle-aged male workers in Japan SO Scandinavian Journal of Work, Environment & Health PD 9VL PY 2011 BP 411 EP 417 IS 5 DI 10.5271/sjweh.3168 WP https://www.sjweh.fi/show_abstract.php?abstract_id=3168 DE cardiovascular disease; cardiovascular event; cardiovascular risk factor; coronary heart disease; follow-up study; Japan; sleep; sleep duration; stroke; worker SN 0355-3140 AB '

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OBJECTIVES ': 'Although previous epidemiological studies have investigated the relationship between sleep duration and various cardiovascular events, the results have been inconsistent. Accordingly, we conducted a follow-up survey to investigate the relationship between sleep duration and cardiovascular events among male workers, accounting for occupational factors that might confound the true relationship.

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METHODS ': 'A total of 2282 male employees aged 35–54 years based in a factory in Japan were followed for 14 years. The risk of cardiovascular events was compared among 4 groups stratified based on sleep duration at baseline (<6, 6–6.9, 7–7.9, and ≥8 hours). Cardiovascular events included stroke, coronary events and sudden cardiac death. The hazard ratios for events were calculated using a Cox proportional hazards model, with the 7–7.9-hour group serving as a reference. The model was adjusted for potential confounders including traditional cardiovascular risk factors and working characteristics.

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RESULTS ': 'During 14 years of follow-up, 64 cardiovascular events were recorded including 30 strokes, 27 coronary events and 7 sudden cardiac deaths. After adjustment for possible confounders, the hazard ratios for cardiovascular and coronary events in the <6-hour group were 3.49 [95% confidence interval (95% CI) 1.30–9.40] and 4.95 (95% CI 1.31–18.73), respectively. There was no significant increment in the risk of stroke for any sleep duration groups.

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CONCLUSION ': 'Short sleep duration (<6 hours) was a significant risk factor for coronary events in a Japanese male working population.

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