Aim: We assessed epigenome-wide DNA methylation (DNAm) differences between migrant and non-migrant Ghanaians. Materials & methods: We used the Illumina Infinium® HumanMethylation450 BeadChip to profile DNAm of 712 Ghanaians in whole blood. We used linear models to detect differentially methylated positions (DMPs) associated with migration. We performed multiple post hoc analyses to validate our findings. Results: We identified 13 DMPs associated with migration (delta-beta values: 0.2-4.5%). Seven DMPs in CPLX2, EIF4E3, MEF2D, TLX3, ST8SIA1, ANG and CHRM3 were independent of extrinsic genomic influences in public databases. Two DMPs in NLRC5 were associated with duration of stay in Europe among migrants. All DMPs were biologically linked to migration-related factors. Conclusion: Our findings provide the first insights into DNAm differences between migrants and non-migrants.

In the advent of rapid urbanisation, migration and epidemiological transition, the extent to which serum uric acid (sUA) affects cardiovascular disease (CVD) risk among Africans is not well understood. We assessed differences in sUA levels and associations with CVD risk among migrant Ghanaians in Europe and non-migrant Ghanaians in rural and urban Ghana.
Baseline data from 633 rural, 916 urban and 2315 migrant participants (40-70 years) from the cross-sectional RODAM study were analysed. Hyperuricaemia was defined as sUA >7 mg/dl in men and >6 mg/dl in women. The 10-year risk of atherosclerotic cardiovascular disease (ASCVD) was calculated using the American College of Cardiology (ACC)/American Heart Association (AHA) risk score which takes into account ethnic minority populations. High CVD risk was defined as ASCVD risk scores ≥7.5%. Logistic regressions were used to assess associations between hyperuricaemia and CVD risk.
Prevalence for hyperuricaemia in rural, urban and migrant participants was 17.4%, 19.1% and 31.7% for men, and 15.9%, 18.2% and 33.2% for women, respectively. Hyperuricaemia was positively associated with elevated CVD risk among rural residents (adjusted OR for men 3.28, 95% CI: 1.21-8.96, 6.36, 95% CI: 2.98-13.56 for women), urban residents (1.12, 95% CI: 0.45-2.81 for men, 2.11, 95% CI: 1.26-3.52 for women) and migrants (1.73, 95% CI: 1.01-2.96 for men, 4.61, 95% CI: 3.05-6.97 for women).
Our study shows variations of sUA levels in different African contexts. Hyperuricaemia is associated with elevated 10-year CVD risk in both migrants and non-migrants. Further studies should identify factors driving associations between sUA and CVD risk in Africans.
Avec l\'avènement de l\'urbanisation rapide, de la migration et de la transition épidémiologique, la mesure dans laquelle l\'acide urique sérique (AUs) affecte le risque de maladie cardiovasculaire (MCV) chez les Africains n\'est pas bien comprise. Nous avons évalué les différences dans les niveaux d\'AUs et les associations avec le risque de MCV chez les ghanéens migrants en Europe et non migrants dans les zones rurales et urbaines du Ghana. MÉTHODES: Les données de base de 633 participants ruraux, 916 urbains et 2.315 migrants, de 40 à 70 ans de l\'étude transversale RODAM ont été analysées. L\'hyperuricémie a été définie comme une AUs > 7 mg/dl chez les hommes et >6 mg/dl chez les femmes. Le risque sur 10 ans de MCV athérosclérosique (MCVAS) a été calculé en utilisant le score de risque de l\'American College of Cardiology (ACC)/American Heart Association (AHA) qui prend en compte les populations des minorités ethniques. Un risque de MCV élevé était défini comme un score de risque MCVAS ≥7,5%. Des régressions logistiques ont été utilisées pour évaluer les associations entre l\'hyperuricémie et le risque de MCV. RÉSULTATS: La prévalence de l\'hyperuricémie chez les participants ruraux, urbains et migrants était de 17,4% ; 19,1% et 31,7% pour les hommes et 15,9%, 18,2% et 33,2% pour les femmes, respectivement. L\'hyperuricémie était positivement associée à un risque élevé de MCV chez les résidents ruraux (OR ajusté 3,28 ; IC95%: 1,21-8,96 pour les hommes, 6,36, IC95%: 2,98-13,56 pour les femmes), les résidents urbains (1,12 ; IC95%: 0,45-2,81 pour les hommes, 2,11 ; IC95%: 1,26-3,52 pour les femmes) et les migrants (1,73 ; IC95%: 1,01-2,96 pour les hommes, 4,61 ; IC95%: 3,05-6,97 pour les femmes).
Notre étude montre des variations des niveaux d\'AUs dans différents contextes africains. L\'hyperuricémie est associée à un risque élevé de MCV sur 10 ans chez les migrants et les non-migrants. Des études plus poussées devraient identifier les facteurs à l\'origine des associations entre le risque d\'AUs et de MCV chez les africains.

Psychosocial stress could be an underlying factor for emerging risk of cardiovascular diseases (CVD) in Africans. We assessed the association between psychosocial stress and estimated CVD risk among non-migrant Ghanaians and migrant Ghanaians living in Europe.
Data from the Research on Obesity and Diabetes among African Migrants (RODAM) study, involving 2315 migrant and 1549 non-migrants aged 40-70 years were used for this study. Psychosocial stress included self-reported stress at work and home, recent negative life events and perceived discrimination. CVD risk was estimated using the pooled cohort equations with estimates ≥7.5% over 10 years defining high CVD risk. Adjusted Odds Ratios (AOR) and 95% confidence intervals (95% CI) were calculated by logistic regression with adjustments for socioeconomic status.
Prevalence for migrant and non-migrants were; 72.5% and 84.9% for psychosocial stress and 35.9% and 27.4% for high estimated CVD risk. Stress at work and home was not associated with a high estimated CVD risk in either group. Recent negative life events were associated with a high estimated CVD risk in non-migrants only (AOR 1.29, 95%CI 1.02-1.68, p = 0.048). Higher levels of perceived discrimination were associated with a high estimated CVD risk in migrants only (AOR 2.74, 95%CI 1.95-3.86, p < 0.001).
Among migrant populations, higher levels of perceived discrimination were associated with a high estimated CVD risk, and this was also true for recent negative life events among non-migrant populations. Further research is needed to identify context specific mechanisms that underlie associations between psychological characteristics and CVD risk.

OBJECTIVE: To compare Type 2 Diabetes Mellitus (T2DM) awareness, treatment and control between Ghanaians resident in Ghana and Europe.
METHODS: Comparisons were made for the 530 participants of the Research on Obesity and Diabetes among African Migrants (RODAM) study with T2DM (25-70 years) living in Amsterdam, Berlin, London, urban Ghana and rural Ghana. We used logistic regression to assess disparities with adjustment for age, sex and education.
RESULTS: T2DM awareness was 51% in rural Ghana. This was lower than levels in Europe ranging from 73% in London (age-sex adjusted odds ratio (OR) = 2.7; 95%CI = 1.2-6.0) to 79% in Amsterdam (OR = 4.7; 95%CI = 2.3-9.6). T2DM treatment was also lower in rural Ghana (37%) than in urban Ghana (56%; OR = 2.6; 95%CI = 1.3-5.3) and European sites ranging from 67% in London (OR = 3.4; 95%CI = 1.5-7.5) to 73% in Berlin (OR = 6.9; 95%CI = 2.9-16.4). In contrast, T2DM control in rural Ghana (63%) was comparable to Amsterdam and Berlin, but higher than in London (40%; OR = 0.4; 95%CI = 0.2-0.9) and urban Ghana (28%; OR = 0.3; 95%CI = 0.1-0.6).
CONCLUSIONS: Our findings suggest that improved detection and treatment of T2DM in rural Ghana, and improved control for people with diagnosed T2DM in London and urban Ghana warrant prioritization. Further work is needed to understand the factors driving the differences.

The aim of this study was to assess the extent to which insulin resistance and beta cell dysfunction account for differences in impaired fasting blood glucose (IFBG) levels in sub-Saharan African individuals living in different locations in Europe and Africa. We also aimed to identify determinants associated with insulin resistance and beta cell dysfunction among this population.
Data from the cross-sectional multicentre Research on Obesity and Diabetes among African Migrants (RODAM) study were analysed. Participants included Ghanaian individuals without diabetes, aged 18-96 years old, who were residing in Amsterdam (n = 1337), Berlin (n = 502), London (n = 961), urban Ghana (n = 1309) and rural Ghana (n = 970). Glucose and insulin were measured in fasting venous blood samples. Anthropometrics were assessed during a physical examination. Questionnaires were used to assess demographics, physical activity, smoking status, alcohol consumption and energy intake. Insulin resistance and beta cell function were determined using homeostatic modelling (HOMA-IR and HOMA-B, respectively). Logistic regression analysis was used to study the contribution of HOMA-IR and inverse HOMA-B (beta cell dysfunction) to geographical differences in IFBG (fasting glucose 5.6-6.9 mmol/l). Multivariate linear regression analysis was used to identify determinants associated with HOMA-IR and inverse HOMA-B.
IFBG was more common in individuals residing in urban Ghana (OR 1.41 [95% CI 1.08, 1.84]), Amsterdam (OR 3.44 [95% CI 2.69, 4.39]) and London (OR 1.58 [95% CI 1.20 2.08), but similar in individuals living in Berlin (OR 1.00 [95% CI 0.70, 1.45]), compared with those in rural Ghana (reference population). The attributable risk of IFBG per 1 SD increase in HOMA-IR was 69.3% and in inverse HOMA-B was 11.1%. After adjustment for HOMA-IR, the odds for IFBG reduced to 0.96 (95% CI 0.72, 1.27), 2.52 (95%CI 1.94, 3.26) and 1.02 (95% CI 0.78, 1.38) for individuals in Urban Ghana, Amsterdam and London compared with rural Ghana, respectively. In contrast, adjustment for inverse HOMA-B had very minor impact on the ORs of IFBG. In multivariate analyses, BMI (β = 0.17 [95% CI 0.11, 0.24]) and waist circumference (β = 0.29 [95%CI 0.22, 0.36]) were most strongly associated with higher HOMA-IR, whereas inverse HOMA-B was most strongly associated with age (β = 0.20 [95% CI 0.16, 0.23]) and excess alcohol consumption (β = 0.25 [95% CI 0.07, 0.43]).
Our findings suggest that insulin resistance, rather than beta cell dysfunction, is more important in accounting for the geographical differences in IFBG among sub-Saharan African individuals. We also show that BMI and waist circumference are important factors in insulin resistance in this population.