A family history of diabetes determines poorer glycaemic control and younger age of diabetes onset in immigrants from the Middle East compared with native Swedes

Aims. - Immigrant populations from the Middle East develop diabetes earlier than indigenous European populations; however, the underlying etiology is poorly understood. This study looked at the risk factors associated with early diabetes onset and, in non-diabetics, glycaemic control in immigrants from Iraq compared with native Swedes. Methods. - This cross-sectional population-based study comprised 1398 Iraqi immigrants and 757 Swedes (ages 30-75 years) residing in the same area of Malmo, Sweden. Outcomes were age at diabetes onset and glycaemic control (HbA(1c)) as assessed by Cox proportional hazards and linear regression, respectively. Results. - In Iraqis vs Swedes, clustering in the family history (in two or more relatives) was more prevalent (23.2% vs 3.6%, P<0.001) and diabetes onset occurred earlier (47.6 years vs 53.4 years, P=0.001). Having an Iraqi background independently raised the hazard ratio (HR) for diabetes onset. Diabetes risk due to family history was augmented by obesity, with the highest HRs observed in obese participants with clustering in the family history (HR: 5.1, 95% CI: 3.2-8.2) after adjusting for country of birth and gender. In participants without previously diagnosed diabetes (Iraqis: n=1270; Swedes: n=728), HbA(1c), levels were slightly higher in Iraqis than in Swedes (4.5% vs 4.4%, P=0.038). This difference was explained primarily by clustering in the family history rather than age, obesity, lifestyle or socioeconomic status. Conclusion. - The study shows that the greater predisposition to diabetes in Middle Eastern immigrants may be explained by a more extensive family history of the disorder; clinical interventions tailored to Middle Eastern immigrants with such a family history are thus warranted. (C) 2014 Elsevier Masson SAS. All rights reserved.