Epidemiological studies on regional differences in suicide mortality and its correlation with socioeconomic factors

To investigate regional differences in suicide mortality and its correlation with socioeconomic factors during the 1975-1990 period, we analyzed annual change in suicide mortality and 18 socioeconomic indicators among each prefectures in Japan. Annual course of age-adjusted mortality from suicide during the 1975-1985 period differed between males (increasing) and females (decreasing), because of rapidly increase in suicide mortality for middle-aged males. During the 1986-1990 period, suicide mortality decreased in both males and females. A census characteristic that suicide mortality was higher in rural districts than in urban districts intensified annually until 1985 and weakened thereafter. The factor analysis of socioeconomic indicators revealed that 1st factor was recognized as the industrial and economic activity. A high inverse correlation was observed between age-adjusted mortality from suicide and the 1st factor for males and females. In males this tendency continued until the end of the 1980s. On the whole, correlation coefficients between age-adjusted mortality from suicide and the socioeconomic indicators in males were much higher than that in females. The indicators whose annual change differed remarkably between the prefectures with an increase and a decrease in suicide mortality for males were amount of savings and frequency of bankruptcy. Therefore they were considered to be closely related to suicide mortality.