The contribution of charcoal burning to the rise and decline of suicides in Hong Kong from 1997–2007

Background There has been scant research exploring the relationship between choice of method (means) of selfinflicted death, and broader social or contextual factors. The recent emergence and growth of suicide using carbon monoxide poisoning resulting from burning charcoal in an enclosed space (hereafter, ‘‘charcoal burning’’) was related to an increase in the overall suicide rate in Hong Kong. The growth of this method coincided with changing economic conditions. This paper expands upon previous work to explore possible relationships further. Purpose This study aims to discern the role of charcoal burning in overall suicide rate transition during times of both economic recession and expansion, as captured in the unemployment rate of Hong Kong, and to examine whether there was evidence of an effect from means-substitution. Methods Age and gender specific suicide rates in Hong Kong by suicide methods from 1997 to 2007 were calculated. To model the transition of suicide rate by different methods, Poisson regression analyses were employed. Results Charcoal burning constituted 18.3% of all suicides, 88% of which involved individuals drawn from the middle years (25–59) of life. During both periods of rising and declining unemployment, charcoal burning played an important role in the changing suicide rates, and this effect was most prominent among for those in their middle years. Means-substitution was found among the married women during the period of rate advancement (1997–2003). Conclusions Compared to others, working-age adults preferentially selected carbon monoxide poisoning from charcoal burning