Immigrant enclaves and risk of diabetes: a prospective study

BACKGROUND The diversity of the Swedish population has increased substantially over the past three decades. The aim of this study was to assess whether living in an ethnic enclave is associated with risk of diabetes mellitus (DM) among first and second-generation immigrants and native Swedes. METHODS Cumulative incidence of DM in three urban municipalities was assessed from 2006-2010 by linking records from the national census, multi-generational family register, and prescription drug register. Immigrant enclaves were identified using Moran's Index. Multi-level logistic regression was used to assess the relationship between enclave residence and risk of DM for three groups: Iraqi immigrants, non-Iraqi immigrants, and native Swedes (N = 887,603). RESULTS The cumulative incidence of DM was greater in Iraqi enclaves compared to other neighborhoods (4.7% vs. 2.3%). Among Iraqi immigrants, enclave residence was not associated with odds of DM (Odds ratio (OR): 1.03, 95% Confidence Interval (CI): 0.86 - 1.24). Among other immigrants, enclave residence was not associated with DM after accounting for neighborhood deprivation. Among native Swedes, enclave residence was associated with elevated risk of DM even after accounting for neighborhood deprivation and individual-level characteristics (OR: 1.23, 95% CI: 1.11 - 1.36). CONCLUSIONS Residential ethnic composition is associated with DM but this relationship differs across ethnic group. Enclave residence is not associated with increased odds of DM for immigrants, regardless of their nation of origin, but it is associated with increased likelihood of DM for native Swedes.