Significant correlation of yearly suicide rates with the rate of unemployment among men results in a rapid increase of suicide in Mie Prefecture, Japan

Abstract

The number of suicides in Japan has increased from approximately 22 000 per year in 1988–1997 to >30 000 per year since then. Likewise, the number of suicides has been increasing in Mie Prefecture. Many researchers consider that a major factor related to the number of suicides is an increase of unemployment in men;1,2 but it has not been described clearly in Mie Prefecture so far. According to Yoshioka, Mie Prefecture had intermediate suicide rates similar to the rates for Japan as a whole.3 It is possible to analyze enough suicide data for this prefecture to investigate the causes of suicide in detail. In the present study, we investigated the incidence and the circumstances of all suicide cases between 1989 and 2002 in cooperation with the First Department of Criminal Investigation of the Mie Prefectural Police Headquarters, and we investigated the unemployment rate from 1989 to 2002 in cooperation with the Department of Work in Mie Prefecture. In Japan, the annual rate of unemployment among the whole Japanese population and the current rate of unemployment are available for each Prefecture every 5 years, but the annual rate of unemployment is not available in each Prefecture. Therefore we calculated the correlation between the rate of unemployment every 5 years in the total Japanese population and that in Mie Prefecture for each sex. The correlations were r = 0.80 and r = 0.97 for men and women, respectively. Accordingly we considered that the rate of unemployment in the Japanese total reflected the rate of unemployment in Mie Prefecture. We focused on the correlation of yearly suicide rates in Mie Prefecture from 1989 to 2002, with the rate of unemployment in Japan from 1989 to 2002. The statistical analysis was performed using single regression analysis and Fisher’s exact test. During the test period, 3276 male and 1772 female suicides were reported to Mie Prefectural Police Headquarters. The suicide rates by sex were 26.2 (male) and 13.4 (female) per 100 000 (P < 0.05). Among the causative factors, ‘economic difficulties (including suffering from unemployment)’ was the second most prevalent in men (20.0%), and the least prevalent in women (5.0%). The yearly suicide rates for men correlated significantly with the unemployment rate in Japan: r(14) = 0.92, P < 0.001; the yearly sucidie rates for women also showed some correlation with the unemployment rate in Japan: r(14) = 0.56, P = 0.04. The factor of ‘economic difficulties’ is particularly relevant for the increase in suicide in men. When economic conditions become worse, people are exposed to more stress in the workplace.3–6 It should be noted that suicide rates were less related to the level of unemployment than to the change in situation from employment to unemployment. One typical case was the significant increase in suicide rates in the year 1997–1998 when such worsened changes of working conditions were observed. In 1997 and 1998, yearly suicide rates were 17.19 and 26.91, and the unemployment rates were 3.5 and 4.3, respectively. We conclude that psychosocial health care should be considered to be part of occupational affairs by industry physicians, primary care physicians and psychiatrists in order to prevent suicide, which is now a national increasing trend in Japan. When the patient is in a bad situation because of unemployment, the family and medical staff should be aware of the correspondence between suicide rates and unemployment.