Risk of hospitalization for type 2 diabetes in first- and second-generation immigrants in Sweden: a nationwide follow-up study.

OBJECTIVES This is the first nationwide study with the aim to analyze whether there is an association between country of birth in first-generation immigrants and hospitalization for type 2 diabetes (T2D), and to study whether any such association remains in second-generation immigrants. DESIGN In this follow-up study, the Swedish Hospital Discharge Register was used to identify all hospital diagnoses of T2D in first- and second-generation immigrants in Sweden between January 1, 1964 and December 31, 2007. Hospitalization rate ratios standardized with regard to gender, age, geographical region, socioeconomic status, obesity, and family history of hospitalization for T2D were estimated in first- and second-generation immigrants. RESULTS Both increased and decreased risks of hospitalization for T2D were shown for several first-generation immigrant groups. However, only second-generation immigrants with Finnish or former Yugoslavian parents had higher rates of hospitalization for T2D than the reference group. No other differences remained in the second-generation immigrants. CONCLUSIONS The present study suggests that ethnic environmental factors may be more important than ethnic genetic factors in explaining the observed variation in hospitalization for T2D among first-generation immigrants.