Karlijn Meeks

Rationale and cross-sectional study design of the Research on Obesity and type 2 Diabetes among African Migrants: the RODAM study.

Introduction Obesity and type 2 diabetes (T2D) are highly prevalent among African migrants compared with European descent populations. The underlying reasons still remain a puzzle. Gene–environmental interaction is now seen as a potential plausible factor contributing to the high prevalence of obesity and T2D, but has not yet been investigated. The overall aim of the Research on Obesity and Diabetes among African Migrants (RODAM) project is to understand the reasons for the high prevalence of obesity and T2D among sub-Saharan Africans in diaspora by (1) studying the complex interplay between environment (eg, lifestyle), healthcare, biochemical and (epi)genetic factors, and their relative contributions to the high prevalence of obesity and T2D; (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. Methods and analysis RODAM is a multicentre cross-sectional study among homogenous sub-Saharan African participants (ie, Ghanaians) aged >25 years living in rural and urban Ghana, the Netherlands, Germany and the UK (http://rod-am.eu/). Standardised data on the main outcomes, genetic and non-genetic factors are collected in all locations. The aim is to recruit 6250 individuals comprising five subgroups of 1250 individuals from each site. In Ghana, Kumasi and Obuasi (urban stratum) and villages in the Ashanti region (rural stratum) are served as recruitment sites. In Europe, Ghanaian migrants are selected through the municipality or Ghanaian organisations registers. Ethics and dissemination Ethical approval has been obtained in all sites. This paper gives an overview of the rationale, conceptual framework and methods of the study. The differences across locations will allow us to gain insight into genetic and non-genetic factors contributing to the occurrence of obesity and T2D and will inform targeted intervention and prevention programmes, and provide the basis for improving diagnosis and treatment in these populations and beyond.

Variations in hypertension awareness, treatment, and control among Ghanaian migrants living in Amsterdam, Berlin, London, and nonmigrant Ghanaians living in rural and urban Ghana-the RODAM study

Objectives: Hypertension is a major burden among African migrants, but the extent of the differences in prevalence, treatment, and control among similar African migrants and nonmigrants living in different contexts in high-income countries and rural and urban Africa has not yet been assessed. We assessed differences in hypertension prevalence and its management among relatively homogenous African migrants (Ghanaians) living in three European cities (Amsterdam, London, and Berlin) and nonmigrants living in rural and urban Ghana. Methods: A multicenter cross-sectional study was conducted among Ghanaian adults (n = 5659) aged 25–70 years. Comparisons between sites were made using prevalence ratios with adjustment for age, education, and BMI. Results: The age-standardised prevalence of hypertension was 22 and 28% in rural Ghanaian men and women. The prevalence was higher in urban Ghana [men, 34%; adjusted prevalence ratio = 1.37, 95% confidence interval (CI), 1.10–1.70]; and much higher in migrants in Europe, especially in Berlin (men, 57%; prevalence ratio = 2.21, 1.78–2.73; women, 51%; prevalence ratio = 1.74, 1.45–2.09) than in rural Ghana. Hypertension awareness and treatment levels were higher in Ghanaian migrants than in nonmigrant Ghanaians. However, adequate hypertension control was lower in Ghanaian migrant men in Berlin (20%; prevalence ratio = 0.43 95%, 0.23–0.82), Amsterdam (29%; prevalence ratio = 0.59, 0.35–0.99), and London (36%; prevalence ratio = 0.86, 0.49–1.51) than rural Ghanaians (59%). Among women, no differences in hypertension control were observed. About 50% of migrants to 85% of rural Ghanaians with severe hypertension (Blood pressure > 180/110) were untreated. Antihypertensive medication prescription patterns varied considerably by site. Conclusion: Hypertension prevalence, awareness, and treatment levels were generally higher in African migrants, but blood pressure control level was lower in Ghanaian migrant men compared with their nonmigrant peers. Further work is needed to identify key underlying factors to support prevention and management efforts. Supplement Figure 1, http://links.lww.com/HJH/A831.

Association between socioeconomic position and the prevalence of type 2 diabetes in Ghanaians in different geographic locations: the RODAM study

Background The prevalence of diabetes has been shown to be socially patterned but the direction of the association in low-income countries and among migrant populations in Europe has varied in the literature. This study examined the association between socioeconomic position (SEP) and diabetes in Ghanaians in Europe and in Ghana. Methods Data were derived from the multicentre Research on Obesity and Diabetes among African Migrants (RODAM) study of Ghanaian adults aged 25–70 years residing in Europe (Amsterdam, Berlin and London) and in urban and rural Ghana. Educational attainment (elementary, secondary or higher) and occupational class (low or high) were used as indicators of SEP. Age-standardised prevalence of diabetes and prevalence ratios were evaluated separately for men and women of different SEP in Ghana and Europe. Results A total of 5290 participants were included in the analyses. The prevalence of diabetes decreased with increasing level of education in Ghanaian men and women in Europe and in men in urban Ghana, whereas diabetes prevalence increased with increasing level of education in men and women in rural Ghana. The association between occupational class and the prevalence of diabetes followed a less consistent pattern in men and women in the different locations. Conclusions The association of diabetes and SEP differed in rural Ghana compared with urban settings in Ghana and Europe and comparing men and women, highlighting the complex interaction of SEP and the development of diabetes. These findings have important implications for diabetes prevention strategies in Ghanaians in different locations.

Innovative ways of studying the effect of migration on obesity and diabetes beyond the common designs: lessons from the RODAM study

Type 2 diabetes and obesity are major global public health problems, with migrant populations in high‐income countries being particularly affected. Type 2 diabetes and obesity are also major threats in low‐ and middle‐income countries, from which most migrant populations originate. Transitioning of societies and the resulting changes in lifestyles are thought to be major driving forces, but the key specific factors within this broad category still need to be determined. Migrant studies provide a unique opportunity to understand the potential underlying causes of these conditions, but current research is mainly geared toward analyzing the differences between migrants and the host populations in the countries of settlement. For better understanding, there is a need to extend migrant health research across national boundaries. This review discusses innovative ways of studying the effect of migration on type 2 diabetes and obesity beyond the common designs and the relevance of extending migrant health studies across national boundaries in the current era of increasing global migration. Specifically, we describe the burden and different methods for conducting migrant studies. We use the Research on Obesity and Diabetes among African Migrants (RODAM) study as a case study, discussing the methods, some results, and lessons learned, including challenges and an essential recipe for success that may guide future migrant health research.

Prevalence of type 2 diabetes and its association with measures of body composition among African residents in the Netherlands--The HELIUS study

AIMS To compare type 2 diabetes prevalence among three ethnic groups resident in the Netherlands: Ghanaians, African Surinamese and Dutch origin. Secondly, to determine the contribution of measures of body composition to ethnic differences in type 2 diabetes. METHODS Baseline data from Ghanaian (n=1873), African Surinamese (n=2189) and Dutch (n=2151) origin participants of the HELIUS study (aged 18-70 years) were analyzed. Type 2 diabetes was determined according to the WHO criteria. Logistic regression tested ethnic differences in type 2 diabetes and the contribution of body fat percentage and waist-to-hip ratio. RESULTS Among men, type 2 diabetes prevalence was higher in Ghanaians (14.9%) than in African Surinamese (10.4%) and Dutch (5.0%). Among women, type 2 diabetes prevalence in Ghanaian (11.1%) was higher than in Dutch (2.3%), but similar to African Surinamese (11.5%). After adjusting for age, body fat percentage and waist-to-hip ratio, the odds ratios for having type 2 diabetes were 1.55 (95% CI: 1.12-2.15) for Ghanaian men compared with African Surinamese and 4.19 (95% CI: 2.86-6.12) compared with Dutch. Among women these odds ratios were 0.94 (95% CI: 0.70-1.26) and 4.78 (95% CI: 2.82-8.11). CONCLUSIONS The higher prevalence of type 2 diabetes among Ghanaian compared with African Surinamese men suggests a need to distinguish between African descent populations when assessing their type 2 diabetes risk. The higher odds for type 2 diabetes among Ghanaians cannot be attributed to differences in body composition. Further research on the contribution of lifestyle factors as well as genetic and epigenetic factors is needed to identify the reasons for the observed disparities.

Food consumption, nutrient intake, and dietary patterns in Ghanaian migrants in Europe and their compatriots in Ghana

ABSTRACT Background: West African immigrants in Europe are disproportionally affected by metabolic conditions compared to European host populations. Nutrition transition through urbanisation and migration may contribute to this observations, but remains to be characterised. Objective: We aimed to describe the dietary behaviour and its socio-demographic factors among Ghanaian migrants in Europe and their compatriots living different Ghanaian settings. Methods: The multi-centre, cross-sectional RODAM (Research on Obesity and Diabetes among African Migrants) study was conducted among Ghanaian adults in rural and urban Ghana, and Europe. Dietary patterns were identified by principal component analysis. Results: Contributions of macronutrient to the daily energy intake was different across the three study sites. Three dietary patterns were identified. Adherence to the ‘mixed’ pattern was associated with female sex, higher education, and European residency. The ‘rice, pasta, meat, and fish’ pattern was associated with male sex, younger age, higher education, and urban Ghanaian environment. Adherence to the ‘roots, tubers, and plantain’ pattern was mainly related to rural Ghanaian residency. Conclusion: We observed differences in food preferences across study sites: in rural Ghana, diet concentrated on starchy foods; in urban Ghana, nutrition was dominated by animal-based products; and in Europe, diet appeared to be highly diverse.

[Accepted Manuscript] Innovative ways of studying the effect of migration on obesity and diabetes beyond the common designs: lessons from the RODAM study.

Type 2 diabetes and obesity are major global public health problems, with migrant populations in high‐income countries being particularly affected. Type 2 diabetes and obesity are also major threats in low‐ and middle‐income countries, from which most migrant populations originate. Transitioning of societies and the resulting changes in lifestyles are thought to be major driving forces, but the key specific factors within this broad category still need to be determined. Migrant studies provide a unique opportunity to understand the potential underlying causes of these conditions, but current research is mainly geared toward analyzing the differences between migrants and the host populations in the countries of settlement. For better understanding, there is a need to extend migrant health research across national boundaries. This review discusses innovative ways of studying the effect of migration on type 2 diabetes and obesity beyond the common designs and the relevance of extending migrant health studies across national boundaries in the current era of increasing global migration. Specifically, we describe the burden and different methods for conducting migrant studies. We use the Research on Obesity and Diabetes among African Migrants (RODAM) study as a case study, discussing the methods, some results, and lessons learned, including challenges and an essential recipe for success that may guide future migrant health research.

Cardiovascular disease risk prediction in sub-Saharan African populations — Comparative analysis of risk algorithms in the RODAM study

BACKGROUND Validated absolute risk equations are currently recommended as the basis of cardiovascular disease (CVD) risk stratification in prevention and control strategies. However, there is no consensus on appropriate equations for sub-Saharan African populations. We assessed agreement between different cardiovascular risk equations among Ghanaian migrant and home populations with no overt CVD. METHODS The 10-year CVD risks were calculated for 3586 participants aged 40-70years in the multi-centre RODAM study among Ghanaians residing in Ghana and Europe using the Framingham laboratory and non-laboratory and Pooled Cohort Equations (PCE) algorithms. Participants were classified as low, moderate or high risk, corresponding to <10%, 10-20% and >20% respectively. Agreement between the risk algorithms was assessed using kappa and correlation coefficients. RESULTS 19.4%, 12.3% and 5.8% were ranked as high 10-year CVD risk by Framingham non-laboratory, Framingham laboratory and PCE, respectively. The median (25th-75th percentiles) estimated 10-year CVD risk was 9.5% (5.4-15.7), 7.3% (3.9-13.2) and 5.0% (2.3-9.7) for Framingham non-laboratory, Framingham laboratory and PCE, respectively. The concordance between PCE and Framingham non-laboratory was better in the home Ghanaian population (kappa=0.42, r=0.738) than the migrant population (kappa=0.24, r=0.732) whereas concordance between PCE and Framingham laboratory was better in migrant Ghanaians (kappa=0.54, r=0.769) than the home population (kappa=0.51, r=0.758). CONCLUSION CVD prediction with the same algorithm differs for the migrant and home populations and the interchangeability of Framingham laboratory and non-laboratory algorithms is limited. Validation against CVD outcomes is needed to inform appropriate selection of risk algorithms for use in African ancestry populations.

Smoking prevalence differs by location of residence among Ghanaians in Africa and Europe: The RODAM study.

Background Although the prevalence of smoking is low in Ghana, little is known about the effect of migration on smoking. Comparing Ghanaians living in their country of origin to those living in Europe offers an opportunity to investigate smoking by location of residence and the associations between smoking behaviours and migration-related factors. Methods Data on a relatively homogenous group of Ghanaians living in London (n = 949), Amsterdam (n = 1400), Berlin (n = 543), rural Ghana (n = 973) and urban Ghana (n = 1400) from the cross-sectional RODAM (Research on Obesity & Diabetes in African Migrants) study were used. Age-standardized prevalence rates of smoking by location of residence and factors associated with smoking among Ghanaian men were estimated using prevalence ratios (PR: 95% CIs). Results Current smoking was non-existent among women in rural and urban Ghana and London but was 3.2% and 3.3% in women in Amsterdam and Berlin, respectively. Smoking prevalence was higher in men in Europe (7.8%) than in both rural and urban Ghana (4.8%): PR 1.91: 95% CI 1.27, 2.88, adjusted for age, marital status, education and employment. Factors associated with a higher prevalence of smoking among Ghanaian men included European residence, being divorced or widowed, living alone, Islam religion, infrequent attendance at religious services, assimilation (cultural orientation), and low education. Conclusion Ghanaians living in Europe are more likely to smoke than their counterparts in Ghana, suggesting convergence to European populations, although prevalence rates are still far below those in the host populations.

Chronic kidney disease burden among African migrants in three European countries and in urban and rural Ghana: the RODAM cross-sectional study

Background Chronic kidney disease (CKD) is a major burden among sub-Saharan African (SSA) populations. However, differences in CKD prevalence between rural and urban settings in Africa, and upon migration to Europe are unknown. We therefore assessed the differences in CKD prevalence among homogenous SSA population (Ghanaians) residing in rural and urban Ghana and in three European cities, and whether conventional risk factors of CKD explained the observed differences. Furthermore, we assessed whether the prevalence of CKD varied among individuals with hypertension and diabetes compared with individuals without these conditions. Methods For this analysis, data from Research on Obesity & Diabetes among African Migrants (RODAM), a multi-centre cross-sectional study, were used. The study included a random sample of 5607 adult Ghanaians living in Europe (1465 Amsterdam, 577 Berlin, 1041 London) and Ghana (1445 urban and 1079 rural) aged 25-70 years. CKD status was defined according to severity of kidney disease using the combination of glomerular filtration rate (G1-G5) and albuminuria (A1-A3) levels as defined by the 2012 Kidney Disease: Improving Global Outcomes severity classification. Comparisons among sites were made using logistic regression analysis. Results CKD prevalence was lower in Ghanaians living in Europe (10.1%) compared with their compatriots living in Ghana (13.3%) even after adjustment for age, sex and conventional risk factors of CKD [adjusted odds ratio (OR) = 0.70, 95% confidence interval (CI) 0.56-0.88, P = 0.002]. CKD prevalence was markedly lower among Ghanaian migrants with hypertension (adjusted OR = 0.54, 0.44-0.76, P = 0.001) and diabetes (adjusted OR = 0.37, 0.22-0.62, P = 0.001) compared with non-migrant Ghanaians with hypertension and diabetes. No significant differences in CKD prevalence was observed among non-migrant Ghanaians and migrant Ghanaians with no hypertension and diabetes. Among Ghanaian residents in Europe, the odds of CKD were lower in Amsterdam than in Berlin, while among Ghanaian residents in Ghana, the odds of CKD were lower in rural Ghana (adjusted OR = 0.68, 95% CI 0.53-0.88, P = 0.004) than in urban Ghana, but these difference were explained by conventional risk factors. Conclusion Our study shows important differences in CKD prevalence among Ghanaians living in Europe compared with those living in Ghana, independent of conventional risk factors, with marked differences among those with hypertension and diabetes. Further research is needed to identify factors that might explain the observed difference across sites to implement interventions to reduce the high burden of CKD, especially in rural and urban Ghana.