Abstract

OBJECTIVES
Karoshi is a word meaning death from work-overload. Work-related diseases due to continuous overwork are primarily cerebro- and cardio-vascular in nature. In Korea, despite an increase in the incidence of Karoshi, it is not easy to recognise by workmen's compensation in Korea. This study intended to establish basic information concerning the incidence of Karoshi.
METHODS
219 cases were collected based on workers' compensation records of three Busan Regional Centers of Labor Welfare Corporation from 1991 to 1999. The size of workplace, occupation, daily working time, type of working schedule, job tenures, characters of work-overload and duration of work-overload were investigated according of subgroups of general characteristics. Both univariate and multiple logistic regression analyses were used to estimate the relationship between risk factors and a recognition of Karoshi.
RESULTS
1. 61.6 % of total cases were recognized as Karoshi. 30.6 % occurred in a small workplace of less than 50 workers, 34.7 % were drivers or guards, and 48.8 % were more than 50 years old. Additionally, 29.6 % worked more than 12 hours, 37.5 % were irregular hours and shift workers and 21.5 % of the total had been on the job less than 6 months. 2. Of the causes of death, 49.8 % was cerebro-vascular diseases and it was more than cardio-vascular ones. And 80.4 % of total cases was belonged to the recognition-category of the Labour Ministry's Law. The previous disease history was found on 49.8 % of all cases. Of them, hypertension was most common as 21.9 %. 3. 53.9 % of patients were exposed to job hazards such as driving, monitoring, guarding, risky jobs and frequent long-term official trips. 64.7 % recorded a increased work-overload of job contents and working hours. Of the several types of work-overload, 42.5 % displayed long-term physical and psychotic work-overload and 22.2 % exhibited job characteristic work-overload. 4. In this study, work-overload was associated with the incidence of Karoshi in 76.3 % of cases. This rate was higher than the recognition of Workmen's compensation recorded by the Korea Labor Welfare Corporation. Of these, 43.6 % belonged to sufficient factors, 10.4 % partial factors, and 22.3 % were due to aggravating factors. 5. Logistic regression demonstrated that death due to cerebro- and cardio-vascular disease, shorttenure within 6 month was significantly associated with a recognition of Karoshi (p=0.034, OR=3.00, C I = 1 . 0 9~8.30/p=0.016, OR=6.76, CI=1.43~32.07 respectively) and that an increase of work-overload was also associated, but its statistical significance was slightly lower(p=0.081, OR=2.02, CI=0.91.~4.46 ) . However, no association was found between this recognition and overtime work, hazardous job, irregular work schedule, low-income, injury-onset place, or small size of workplace. The elderly group(>50years old) and those with a previous disease history were negatively associated with recognition although the statistical association was low.
CONCLUSIONS
Karoshi in Busan occurred frequently in a small workplace of less than 50 workers, especially drivers or guards. Additionally, these cases worked more than 12 hours, were irregular hours and shift workers. The death due to cerebro- and cardio-vascular disease, short-tenure within 6 month was significantly associated with a recognition of Karoshi. However Karoshi in this study occurred frequently in overtime work and high risk groups of work-overload. Therefore, for prevention of Karoshi, work-overload and overtime work need improved and controled.

• Keywords: Karoshi;Work-overload;Shift work;Overtime work;Cerebro- and cardiovascular disease;Industrial accident compensation