The importance of alcoholic beverage type for suicide in Japan: a time-series analysis, 1963-2007

Japan has one of the highest suicide rates in the world. Cohort analysis has suggested that alcohol consumption is a risk factor for suicide in Japan. However, this relationship has not been observed at the population level when a measure of per capita total alcohol consumption has been analysed. The present study employed a time-series analysis to examine whether these contradictory findings may be due to the existence of beverage-specific effects on suicide.

An autoregressive integrated moving average model was used to assess the relationship between the consumption of different types of alcohol and suicide rates from 1963 to 2007. The data comprised age-adjusted suicide rates for the ages 15-69, and information on beverage-specific alcohol consumption per capita (15+). The unemployment rate was included as a control variable.

During 1963-2007, male suicide rates increased substantially whereas female rates decreased slightly. Consumption of distilled spirits was significantly related to male suicide rates (but not in women) with a 1L increase in consumption associated with a 21.4% (95% confidence interval: 3.2-42.9) increase in male suicide rates. There was no statistically significant relationship between suicide and any other form of alcohol consumption (beer, wine, other alcohol).

This is the first study that has shown an association between spirits consumption and male suicide in Japan. Potentially beneficial policy changes include increasing spirits prices through taxation, reducing the physical availability of alcohol and discouraging the practice of heavy drinking.