KAROSHI: DEATH FROM OVERWORK
Takashi Haratani

What Is Karoshi?
Karoshi is a Japanese word which means death from overwork. The phenomenon was first identified in Japan, and the word is being adopted internationally (Drinkwater 1992). Uehata (1978) reported 17 karoshi cases at the 51st annual meeting of the Japan Association of Industrial Health. Among them seven cases were compensated as occupational diseases, but ten cases were not. In 1988 a group of lawyers established the National Defense Counsel for Victims of Karoshi (1990) and started telephone consultation to handle inquiries about karoshi-related workers' compensation insurance. Uehata (1989) described karoshi as a sociomedical term that refers to fatalities or associated work disability due to cardiovascular attacks (such as strokes, myocardial infarction or acute cardiac failure) which could occur when hypertensive arteriosclerotic diseases are aggravated by a heavy workload. Karoshi is not a pure medical term. The media have frequently used the word because it emphasizes that sudden deaths (or disabilities) were caused by overwork and should be compensated. Karoshi has become an important social problem in Japan.

Research on Karoshi
Uehata (1991a) conducted a study of 203 Japanese workers (196 males and seven females) who had cardiovascular attacks. They or their next of kin consulted with him regarding workers' compensation claims between 1974 and 1990. A total of 174 workers had died; 55 cases had already been compensated as occupational disease. A total of 123 workers had suffered strokes (57 arachnoidal bleedings, 46 cerebral bleedings, 13 cerebral infarctions, seven unknown types); 50, acute heart failure; 27, myocardial infarctions; and four, aortic ruptures. Autopsies were performed in only 16 cases. More than half of the workers had histories of hypertension, diabetes or other atherosclerotic problems. A total of 131 cases had worked for long hours-more than 60 hours per week, more than 50 hours overtime per month or more than half of their fixed holidays. Eighty-eight workers had identifiable trigger events within 24 hours before their attack. Uehata concluded that these were mostly male workers, working for long hours, with other stressful overload, and that these working styles exacerbated their other lifestyle habits and resulted in the attacks, which were finally triggered by minor work-related troubles or events.

Karasek Model and Karoshi
According to the demand-control model by Karasek (1979), a high-strain job-one with a combination of high demand and low control (decision latitude)-increases the risk of psychological strain and physical illness; an active job-one with a combination of high demand and high control-requires learning motivation to develop new behaviour patterns. Uehata (1991b) reported that the jobs in karoshi cases were characterized by a higher degree of work demands and lower social support, whereas the degree of work control varied greatly. He described the karoshi cases as very delighted and enthusiastic about their work, and consequently likely to ignore their needs for regular rest and so on-even the need for health care. It is suggested that workers in not only high-strain jobs but also active jobs could be at high risk. Managers and engineers have high decision latitude. If they have extremely high demands and are enthusiastic in their work, they may not control their working hours. Such workers may be a risk group for karoshi.

Type A Behaviour Pattern in Japan
Friedman and Rosenman (1959) proposed the concept of Type A behaviour pattern (TABP). Many studies have showed that TABP is related to the prevalence or incidence of coronary heart disease (CHD).

Hayano et al. (1989) investigated the characteristics of TABP in Japanese employees using the Jenkins Activity Survey (JAS). Responses of 1,682 male employees of a telephone company were analysed. The factor structure of the JAS among the Japanese was in most respects equal to that found in the Western Collaborative Group Study (WCGS). However, the average score of factor H (hard-driving and competitiveness) among the Japanese was considerably lower than that in the WCGS.

Monou (1992) reviewed TABP research in Japan and summarized as follows: TABP is less prevalent in Japan than in the United States; the relationship between TABP and coronary heart disease in Japan seems to be significant but weaker than that in the US; TABP among Japanese places more emphasis on "workaholism" and "directivity into the group" than in the US; the percentage of highly hostile individuals in Japan is lower than in the US; there is no relationship between hostility and CHD.

Japanese culture is quite different from those of Western countries. It is strongly influenced by Buddhism and Confucianism. Generally speaking, Japanese workers are organization centred. Cooperation with colleagues is emphasized rather than competition. In Japan, competitiveness is a less important factor for coronary-prone behaviour than job involvement or a tendency to overwork. Direct expression of hostility is suppressed in Japanese society. Hostility may be expressed differently than in Western countries.

Working Hours of Japanese Workers
It is well known that Japanese workers work long hours compared with workers in other developed industrial countries. Normal annual working hours of manufacturing workers in 1993 were 2,017 hours in Japan; 1,904 in the United States; 1,763 in France; and 1,769 in the UK (ILO 1995). However, Japanese working hours are gradually decreasing. Average annual working hours of manufacturing employees in enterprises with 30 employees or more was 2,484 hours in 1960, but 1,957 hours in 1994. Article 32 of the Labor Standards Law, which was revised in 1987, provides for a 40-hour week. The general introduction of the 40-hour week is expected to take place gradually in the 1990s. In 1985, the 5-day work week was granted to 27% of all employees in enterprises with 30 employees or more; in 1993, it was granted to 53% of such employees. The average worker was allowed 16 paid holidays in 1993; however, workers actually used an average of 9 days. In Japan, paid holidays are few, and workers tend to save them to cover absence due to sickness.

Why do Japanese workers work such long hours? Deutschmann (1991) pointed out three structural conditions underlying the present pattern of long working hours in Japan: first, the continuing need of Japanese employees to increase their income; second, the enterprise-centred structure of industrial relations; and third, the holistic style of Japanese personnel management. These conditions were based on historical and cultural factors. Japan was defeated in war in 1945 for the first time in history. After the war Japan was a cheap wage country. The Japanese were used to working long and hard to earn their subsistence. As labour unions were cooperative with employers, there have been relatively few labour disputes in Japan. Japanese companies adopted the seniority-oriented wage system and lifetime employment. The number of hours is a measure of the loyalty and cooperativeness of an employee, and becomes a criterion for promotion. Workers are not forced to work long hours; they are willing to work for their companies, as if the company is their family. Working life has priority over family life. Such long working hours have contributed to the remarkable economic achievements of Japan.

National Survey of Workers' Health
The Japanese Ministry of Labour conducted surveys on the state of employees' health in 1982, 1987 and 1992. In the survey in 1992, 12,000 private worksites employing 10 or more workers were identified, and 16,000 individual workers from them were randomly selected nationwide based on industry and job classification to fill out questionnaires. The questionnaires were mailed to a representative at the workplace who then selected workers to complete the survey.

Sixty-five per cent of these workers complained of physical fatigue due to their usual work, and 48% complained of mental fatigue. Fifty-seven per cent of workers stated that they had strong anxieties, worries or stress concerning their job or working life. The prevalence of stressed workers was increasing, as the prevalence had been 55% in 1987 and 51% in 1982. The main causes of stress were: unsatisfactory relations in the workplace, 48%; quality of work, 41%; quantity of work, 34%.

Eighty-six per cent of these worksites conducted periodic health examinations. Worksite health promotion activities were conducted at 44% of the worksites. Of these worksites, 48% had sports events, 46% had exercise programmes and 35% had health counselling.

National Policy to Protect and Promote Workers' Health
The purpose of the Industrial Safety and Health Law in Japan is to secure the safety and health of workers in workplaces as well as to facilitate the establishment of a comfortable working environment. The law states that the employer shall not only comply with the minimum standards for preventing occupational accidents and diseases, but also endeavour to ensure the safety and health of workers in workplaces through the realization of a comfortable working environment and the improvement of working conditions.

Article 69 of the law, amended in 1988, states that the employer shall make continuous and systematic efforts for the maintenance and promotion of workers' health by taking appropriate measures, such as providing health education and health counselling services to the workers. The Japanese Ministry of Labour publicly announced guidelines for measures to be taken by employers for the maintenance and promotion of workers' health in 1988. It recommends worksite health promotion programmes called the Total Health Promotion Plan (THP): exercise (training and counselling), health education, psychological counselling and nutritional counselling, based on the health status of employees.

In 1992, the guidelines for the realization of a comfortable working environment were announced by the Ministry of Labour in Japan. The guidelines recommend the following: the working environment should be properly maintained under comfortable conditions; work conditions should be improved to reduce the workload; and facilities should be provided for the welfare of employees who need to recover from fatigue. Low-interest loans and grants for small and medium-sized enterprises for workplace improvement measures have been introduced to facilitate the realization of a comfortable working environment.

Conclusion
The evidence that overwork causes sudden death is still incomplete. More studies are needed to clarify the causal relationship. To prevent karoshi, working hours should be reduced. Japanese national occupational health policy has focused on work hazards and health care of workers with problems. The psychological work environment should be improved as a step towards the goal of a comfortable working environment. Health examinations and health promotion programmes for all workers should be encouraged. These activities will prevent karoshi and reduce stress.