Effects of Working Hours on Cerebro-cardiovascular Disease in Korea : A case-crossover study

Cerebro-cardiovascular disease is the second largest cause of death following cancer in Korea, and among occupational diseases and work-related diseases, it is the second largest cause of death following pneumoconiosis. Currently existing researches on work-related cerebro-cardiovascular disease of korea did not designate the group without diseases as a control group. Therefore, most of these researches is on factors as they relate to approval. This crossover study examined the relationship between the attack of work-related cerebro-cardiovascular disease and work hours.

A total of 2909 cases reviewed by the Work-related Disease Adjudication Committee (WDAC) in 2009 were included and 1,878 cases excluded by exclusion criteria, a total of 1,031 cases were selected and analyzed. The hazard period was defined as one week before the onset of disease; the control period was defined as the remaining period, except for the last week of the 3 months after the occurrence of the diseases. The average working-hour per week was set as the independent variable and the onset of cerebro-cardiovascular disease was set as the dependent variable in a conditional logistic analysis. The study results revealed that if the average number of hours worked per week increases, the odds ratio for cerebro-cardiovascular disease significantly increases to 1.452 (95% confidence interval, 1.219–1.724). Sub-group analysis revealed similar results however, the results were not statistically significant in women, those <50 years of age, and those work >60 hours per week.