Background Type 2 diabetes(T2D) is highly prevalent in serious mental illnesses(SMI) such as schizophrenia, bipolar disorder and major depression and is associated with significant morbidity and mortality in these populations. The role of neighbourhoods in exacerbating or buffering T2D risk in individuals with SMI has not been adequately investigated before. The primary aim of this study was to describe the association between neighbourhood socioeconomic disadvantage and serious mental illness - type 2 diabetes comorbidity in an Australian community using routinely collected clinical data. The secondary objective was to determine how much of the between neighbourhood variations in SMI-T2D comorbidity was attributable to neighbourhood socioeconomic disadvantage.
Methods This cross-sectional study considered 3816 individuals with a diagnosis of SMI in Illawarra and Shoalhaven regions of NSW, Australia between 2010 to 2017. Data were analysed using multilevel logistic random intercept modelling that controlled for individual age, gender and country of birth.
Results Individuals with SMI residing in the most disadvantaged neighbourhoods had 3.2 times increased odds of reporting SMI-T2D comorbidity compared with the individuals with SMI residing in the least disadvantaged neighbourhoods (OR 3.20, 95% CI 1.42-7.20 for Q1 vs Q5). Significant neighbourhood level variations in SMI-T2D comorbidity were also observed in our sample (Median Odds Ratio =1.35) and neighbourhood socio economic disadvantage accounted for approximately 17.3% of these variations.
Discussion The findings from this study highlight a potentially important role for geographically targeted public health prevention strategies in order to reduce the public health burden imposed by SMI-T2D comorbidity