Ethnicity Composition and Altitude on Suicide: A Spatial Analysis of Data from Taiwan
摘要
Objective: Few studies have assessed the spatial association of suicide in the world. In this study, we intended to investigate ecological associations with ethnic composition and altitude on suicide rates using national data from Taiwan. Methods: All suicide deaths of residents aged 15 years and over between January 1, 1997 to December 31, 2003 in Taiwan (n=23,380) were included. Definition of suicide deaths encompassed suicide (ICD-9 codes E950-959) and injury undetermined whether accidentally or purposely inflicted (E980-989). We calculated standardized mortality ratios (SMRs) for all 358 townships, the residents was 59,490±74,932 (mean ± SD) per township, and the average area of townships was 100.9±182.6 (mean ± SD) square kilometers. Each township was treated as a unit in the analysis. We used spatial regression to test associations with ethnic composition and altitude, after adjusting for sociodemographic, economic and health care provision indices (including unemployment, marital status, disability, single-person households, home ownership, educational attainment, population density, total number of medical doctors, psychiatric beds, and spatial autocorrelation). Results: Both proportion of aboriginal residents and altitude of residence were significantly and positively associated with SMRs in fully adjusted models (p＜0.001). The effect of ethnic composition and altitude on suicide predominated in the age 15-24 (p＜0.001) and 25-44 (p＜0.001) subgroups. Conclusion: Our results are consistent with previous study finding that altitude is a risk factor for suicide. The novel finding was that the effect of ethnic composition and altitude on suicide was found to be predominated in the young age groups.