Analysis of trend of mortality and patterns of suicide and self-inflicted injury in urban and rural townships in Taiwan: Urbanisation or geography?

Objectives: To analyse trend of mortality rates and patterns of suicide and self-inflicted injury (suicide) in Taiwan and townships with various urbanisation levels in different geographic locations. Methods and Results: 358 townships in Taiwan were classified as 19 areas by geographic locations and urbanisation levels. Suicide standardized mortality ratios (SMRs) and age-standardized rates (ASRs) were calculated based on WHO 2000 standard population. ASRs showed that the secular trend of suicide mortality in Taiwan was a W-shape, with higher rates in 1971, 1982, 2008 (ASR=18.8, 15.1, 15.1/100,000) and lower rates in 1976 (ASR=11.9/100,000) and 1993 (ASR=6.5/100,000). Poisoning was the most prevalent cause (ASR=3.3-9.0/100,000) in early years but hanging has become predominant since 1990 (ASR=3.4-5.8/100,000). Non-domestic gas or vapour were never used but increased sharply from 1998 (ASR=0.1-5.7/100,000), occurring most in northern rural (ASR=5.9/100,000) and suburban (ASR=6.6/100,000) townships during 2006-2008. Jumping from high place increased steadily over the study period (ASR=0.1-1.6/100,000). Urban townships were with lower total suicide mortality (SMR=0.8-0.9, p<0.05) but with higher mortality on suicide by non-domestic gas or vapour (SMR=1.2-2.9, p<0.05) and jumping from high place (SMR=1.6-4.2, p<0.05) than the other areas. Stepwise regression modeling found that urbanisation levels were associated with suicide mortality (F=438, p<0.0001, partial R-square=0.14) and the patterns (F=86-1298, p<0.0001, partial R-square=0.29-0.80). Conclusion: Suicide mortality hasn't been controlled in Taiwan since 1994. Residents in rural and mountainous townships are still vulnerable to suicide and indoor use of non-domestic gas or vapour should be restricted.