Country of birth modifies the associations of body mass and hemoglobin A1c with office blood pressure in Middle Eastern immigrants and native Swedes

Objective: Immigrant populations from the Middle East are at high risk of obesity and diabetes, but paradoxically hypertension is reported to be less prevalent. Studies of the risk factors for hypertension in these populations are scarce. The aim was to study the distribution of cardiovascular and metabolic risk factors in the Middle East immigrant population compared with native Swedes. Methods: A population-based, cross-sectional study of men and women, aged 30-75 years, born in Iraq or Sweden, was conducted in 2010-2012 in Malmo, Sweden. A 75-g oral glucose tolerance test was performed, and sociodemographic and lifestyle data were collected. Results: In participants born in Iraq (n = 1311) vs. participants born in Sweden (n = 698), without a history of cardiovascular disease (CVD), the metabolic syndrome (MetS) was more prevalent in the Iraqis (49.2 vs. 40.3%, P < 0.001). Iraqis presented with higher prevalence rates of all but one MetS entity: elevated blood pressure (BP; 46.0 vs. 61.3%, P < 0.001, data adjusted for age, sex and antihypertensive medication). Being born in Iraq independently decreased the risk of elevated SBP and DBP. Furthermore, higher BMI, waist circumference, pulse rate and hemoglobin A1(c) (HbA1(c)) values presented weaker associations with SBP and DBP in Iraqis than in Swedes. These relationships were confirmed by interactions with the country of birth. Conclusion: BP-regulating mechanisms seem to differ in the Middle Eastern compared with a nonmigrated native European population. Further studies are needed for reaching a better understanding of the mechanisms contributing to CVD in populations of mixed ethnic backgrounds.