Is suicide mortality associated with social fragmentation and deprivation? A Dutch register-based case-control study using individualized neighbourhoods

Background Neighbourhood social fragmentation and socioeconomic deprivation seem to be associated with suicide mortality. However, results are inconclusive, which might be because dynamics in the social context are not well-represented by administratively bounded neighbourhoods at baseline. We used individualised neighbourhoods to examine associations between suicide mortality, social fragmentation, and deprivation for the total population as well as by sex and age group. Methods Using a nested case-control design, all suicides aged 18–64 years between 2007 and 2016 were selected from longitudinal Dutch register data and matched with 10 random controls. Indices for social fragmentation and deprivation were calculated annually for 300, 600 and 1000 metre circular buffers around each subject’s residential address. Results Suicide mortality was significantly higher in neighbourhoods with high deprivation and social fragmentation. Accounting for individual characteristics largely attenuated these associations. Suicide mortality remained significantly higher for women living in highly fragmented neighbourhoods in the fully adjusted model. Age-stratified analyses indicate associations with neighbourhood fragmentation among women in older age groups (40–64 years) only. Among men, suicide risk was lower in fragmented neighbourhoods for those aged 18–39 years and for short-term residents. In deprived neighbourhoods, suicide risk was lower for men aged 40–64 years and long-term residents. Associations between neighbourhood characteristics and suicide mortality were comparable across buffer sizes. Conclusion Our findings suggest that next to individual characteristics, the social and economic context within which people live may both enhance and buffer the risk of suicide