Neighborhood ethnic density and suicide risk among different migrant groups in the four big cities in the Netherlands

Recent studies suggested a favorable association between the ethnic density of the neighborhood and the risk of psychotic disorders among ethnic minorities. In this study, it was investigated whether this so-called 'ethnic density hypothesis' is also relevant to suicide risk, which is not sensitive to bias associated with ethnic differences in access to health care and reflects a broad range of mental health problems.

Suicides in the four big cities in the Netherlands during 2000-2011 were ascertained using the cause of death register of Statistics Netherlands and analyzed in a multilevel Poisson model in relation to individual- and neighborhood-level characteristics.

With increasing non-Western minority density, the adjusted rate ratio (RR) of suicide in non-Western immigrants compared to native Dutch persons decreased from 0.69 to 0.39 (P < 0.001). This was explained by higher suicide rates among Dutch persons (RR = 1.28, P = 0.048) and lower rates among non-Western persons (RR = 0.72, P = 0.004) in neighborhoods with high (>55.9 %) compared to neighborhoods with low non-Western minority density (<36.5 %). Similar results were found for Turkish, Moroccan, Surinamese/Antillean and other non-Western subgroups separately. Compared to personally matched controls, non-Western cases (i.e., those who committed suicide) more often moved house to own-group high-dense areas and less often to own-group low-dense areas in the 5 years prior to suicide.

Our findings support the beneficial influence of the presence of the own ethnic group in the neighborhood on suicide risk among non-Western minorities. As moving to minority more dense areas prior to suicide was observed, this influence of ethnic density as measured on population level may have been underestimated.