Suicide differentials in Australian males and females by various measures of socio-economic status, 1994-98

Objectives: To investigate Australian suicide differentials in males and females by three area-based measures of socio-economic status (SES). Methods: Suicide data for 1994-98 were used to investigate area-based gradients of SES for the Index of Relative Socio-Economic Disadvantage (IRSED) (an overall measure of SES), the Index of Economic Resources (IER), and the Index of Education and Occupation (IEO), using Poisson regression models adjusting for age, country-of-birth and urban-rural residence. Results: After adjusting for age, country-of-birth and urban-rural residence, significant increasing linear trends in suicide risk from high to low quintiles of SES were evident in males for the IRSED (an average multiplicative increase in suicide risk of 8% per quintile), IER (9% increase) and IEO (5% increase). For females, there was no evident SES gradient for the IRSED after adjusting for age, country-of-birth and urban-rural residence, but a significant positive linear trend from high to low quintiles of SES was found for the IER (6% increase per quintile). A significant decreasing linear trend (increasing suicide risk with increasing SES) was evident for the IEO (3% per quintile). Conclusion: Male suicide is positively associated with all three measures of SES examined. Female suicide is significantly associated with the IER (positive association) and IEO (negative), and because of this is not associated with the overall measure of SES. These findings partly explain why female suicide has been found to be poorly correlated with area-based measures of SES. Implications: Specific components of area-based socio-economic status provide a clearer picture of socio-economic suicide differentials in Australian females, with implications for population-based preventive strategies.