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Type 2 diabetes and obesity among sub-Saharan African native and migrant populations: dissection of environment and endogenous predisposition

Final Report Summary - RODAM (Type 2 diabetes and obesity among sub-Saharan African native and migrant populations: dissection of environment and endogenous predisposition)

Executive Summary:
Type-2 diabetes (T2D) and obesity are a global public health problem. Sub-Saharan Africa (SSA) origin populations in Europe have increased substantially for the last few decades. The risks of T2D and obesity are higher in SSA origin populations in Europe than in European host populations. By the same token, T2D and obesity levels are on the rise in many SSA countries. With the increasing prevalence of T2D and obesity and their adverse complications in these populations, there is an urgent need to unravel the differential contribution of risk factors for T2D and obesity to guide prevention and treatment efforts among these populations both in Europe and in Africa.

The RODAM study therefore aimed to understand the reasons for the high prevalence of T2D and obesity among Sub-Saharan African migrants by (1) studying the complex interplay between environmental exposures and genetics and their contributions to the high prevalence of T2D and obesity; (2) to identify specific risk factors within these broad categories to guide intervention programmes and (3) to provide a basic knowledge for improving diagnosis and treatment among a homogenous study population consisting of SSA migrants (Ghanaians) living in 3 European cities (Amsterdam, Berlin & London) and Ghanaians living in rural and urban Ghana (http://www.rod-am.eu/).

The RODAM consortium has conducted one of the largest health assessments among SSA migrants in Europe and their compatriots living in rural and urban Africa. The data collection was completed in October 2014 at all sites with a remarkable 94% (5898/6250) success rate of the intended sample size with data on both interviews and physical measurements. Obesity prevalence was higher among Ghanaians living in urban-Ghana and Europe than in rural-Ghana, ranging from 6.9% and 33.8% in urban-Ghanaian men and women, to 21.5% and 52.3% in London-Ghanaian men and women compared with 1.4% and 8.3% in rural-Ghanaian men and women. The prevalence of T2D was similarly higher in urban-Ghanaians and European-Ghanaians ranging from 6.5% and 5.4% in urban-Ghanaian men and women to 12.6% and 9.5% in Berlin-Ghanaian men and women compared with 1.5% and 3% in rural-Ghanaian men and women, respectively. We identified associations between genetic loci with T2D amongst SSA population. This includes genes directly involved in the pathways underlying glucose transport, insulin secretion and signalling, and risk of T2D. Our study yielded several genome wide significant loci associated with obesity. In addition, the hypothesis driven candidate gene approach showed differential DNA-methylation with T2D of the previously T2D associated genes. Furthermore, we identified several strong associations of lifestyle, nutrition, social factors with obesity and T2D.

The RODAM project has achieved a significant result in collecting these unique data on Ghanaian migrants in European countries and their compatriots living in their home country. Our findings clear show that T2D and obesity are a major burden among SSA migrants in Europe as well as their counterparts living in Africa. The findings also show that both (epi)genetic and environmental factors contribute to the increasing burden of obesity and T2D among these populations. The RODAM study results therefore provide new insights into the aetiology of obesity and T2D will enable new strategies for prevention and treatment of T2D and obesity and their metabolic consequences.

Project Context and Objectives:
Please see page 4-7 of full report (RODAM_Final report to the European Commission)
Project Results:
Please see page 8-34 of full report (RODAM_Final report to the European Commission)
Potential Impact:
Please see page 35-42 of full report (RODAM_Final report to the European Commission)
List of Websites:
RODAM study website address: Task 9.1
Project Coordinators
Dr Charles Agyemang
Academic Medical Centre,
Department of Public Health
University of Amsterdam
Room J2.212
Postbus 22660
1100 DD Amsterdam,
The Netherlands
Email C.O.Agyemang@amc.uva.nl
Phone +31(0)20 5664885
Fax +31(0)20 6972316

Dr Erik Beune
Academic Medical Centre,
Department of Public Health
University of Amsterdam
Room J2.224
Postbus 22660
1100 DD Amsterdam,
The Netherlands
Email E.J.Beune@amc.uva.nl
Phone +31(0)20 566 7646