Phenotypic characterization of first generation Maghrebian migrants with type 2 diabetes: A gender-based comparison with a reference North-Caucasian Belgian cohort

Abstract

Summary Background Ethnicity is a modifying factor affecting the natural history and presentation of T2DM through genetic predisposition and socio-cultural determinants. Among ethnically at-risk subjects are economic migrants from Southern latitudes. In this cross-sectional evaluation, we report the phenotypic characterization of first generation Maghrebian migrants with T2DM, mostly from Morocco, and living in Belgium, with reference to gender-based North-Caucasian Belgian T2DM cohorts. We focused on both the prevalence and determinants of metabolic syndrome (MetS) and its related anthropometry, as well as on the hyperbolic product determinants of glucose homeostasis. Method Fifty-three Maghrebian patients were compared with 558 North-Caucasian Belgian patients, all suffering from T2DM and consecutively followed at the outpatient clinic of St-Luc Academic Hospital in Brussels. In these two groups, we performed HOMA-modeling of insulin sensitivity (S), β-cell function (β), hyperbolic product (β × S) and (β × S) deficit standardized to lifetime. We also collected anthropometric and biochemical characteristics alongside the prevalence of MetS (AHA/NHLBI criteria), its components, and that of micro- and macrovascular complications. Results Maghrebians were younger than North-Caucasians, and diagnosed with diabetes a mean 6 years earlier. There were, however, marked gender differences in anthropometry and glucose homeostasis determinants, with significant differences in Maghrebians males with respect to BMI, waist circumference, fat mass, conicity index, fat-free mass or fat-free mass index. The prevalence of hypertension was lower in Maghrebians, and that of AHA/NHLBI-defined metabolic syndrome was not different between cohorts, nor were HOMA-modeled insulin sensitivity (HOMA S). The hyperbolic product (β × S) was significantly lower in Maghrebians males, who had a more severe insulin secretory defect compared with North-Caucasians. Such β × S defect was especially pronounced in males once standardized to lifetime, in keeping with the pharmaco-therapeutic profile, glucose-lowering therapies and poorer metabolic control. Retinopathy was more frequent and severe in Maghrebians. Conclusion Maghrebians’ true residual β-cell function (β × S) showed accelerated deterioration in T2DM males compared with age-comparable North-Caucasians. Such a faster deterioration hypothesis may easily account for the observed differences in HbA1c and in requirements for glucose-lowering therapies, including insulin monotherapy.