Chronic non-communicable diseases in sub-Saharan Africa
Authors: Alisha N Wade
Journal: The Lancet Global Health (2023)

Modou Jobe and colleagues present data on the prevalence of hypertension, diabetes, and obesity and their co-occurrence in The Gambia.1Jobe M Mactaggart I Bell S et al.Prevalence of hypertension, diabetes, obesity, multimorbidity, and related risk factors among adult Gambians: a cross-sectional nationwide study.Lancet Glob Health. 2024; 12: e54-e65Google Scholar Although there is overwhelming evidence to establish these conditions as public health priorities in middle-income and high-income countries, there are fewer data from lower-income settings. Their study is a timely addition to the literature, which is a reminder that health considerations in impoverished communities are not limited to undernutrition and infectious diseases. The authors provide updated evidence on selected chronic non-communicable diseases (NCDs) in the 2019 Gambia National Eye Health Survey, which provides a useful contrast to previous nationally representative studies from The Gambia. In the 2010 WHO STEPS survey, 29% of participants aged 25–64 years had hypertension,2Cham B Scholes S Ng Fat L Badjie O Mindell JS Burden of hypertension in The Gambia: evidence from a national World Health Organization (WHO) STEP survey.Int J Epidemiol. 2018; 47: 860-871Crossref PubMed Scopus (21) Google Scholar and 40% had overweight or obesity in the Gambia.3Cham B Scholes S Ng Fat L Badjie O Groce NE Mindell JS The silent epidemic of obesity in The Gambia: evidence from a nationwide, population-based, cross-sectional health examination survey.BMJ Open. 2020; 10e033882 Crossref Scopus (8) Google Scholar Although direct comparisons of overall prevalence are difficult due to the older population in the study by Jobe and colleagues, the prevalence of hypertension does appear to have increased in women and men in economically active age groups, which is particularly concerning given the potential effect of disease morbidity and mortality on individual and national productivity. Similar increases were not evident in the prevalence of obesity; although, the significantly higher prevalence of obesity in women persisted. The absence of comparable national-level data for diabetes highlights the paucity of information on chronic NCDs in many countries in sub-Saharan Africa. Indeed, in the 10th edition of the International Diabetes Federation Atlas,4International Diabetes FederationIDF Diabetes Atlas.10th ed. International Diabetes Federation, Brussels2021Google Scholar fewer than half of sub-Saharan African countries had in-country data sources, with extrapolated estimates provided for the remining countries. Robust, nationally representative primary data from The Gambia are therefore welcome, both to improve the accuracy of its national estimates and those in neighbouring countries. Although the study1Jobe M Mactaggart I Bell S et al.Prevalence of hypertension, diabetes, obesity, multimorbidity, and related risk factors among adult Gambians: a cross-sectional nationwide study.Lancet Glob Health. 2024; 12: e54-e65Google Scholar makes a valuable contribution, several questions remain unanswered. The 10·7% prevalence of multimorbidity indicates it is not uncommon for at least two of either hypertension, diabetes, and obesity to occur in the same individual, which is unsurprising as they share risk factors. What remains unclear is whether a syndemic relationship exists between these conditions, in which the outcomes of co-occurring diseases are significantly influenced by differing social and economic contexts. Further work is also necessary to understand the mediators of the sociodemographic risk factors. A marked sex disparity in obesity, for example, is evident in all age groups and even though this has been previously observed in sub-Saharan Africa, it remains poorly understood, and contrasts with high-income countries in which obesity is more evenly distributed.5Wang Y Beydoun MA Min J Xue H Kaminsky LA Cheskin LJ Has the prevalence of overweight, obesity and central obesity levelled off in the United States? Trends, patterns, disparities, and future projections for the obesity epidemic.Int J Epidemiol. 2020; 49: 810-823Crossref PubMed Scopus (21) Google Scholar The absence of a parallel sex disparity in obesity-associated chronic NCDs also deserves further investigation. Understanding the burden of chronic NCDs in lower-income countries in sub-Saharan Africa, such as The Gambia, is a necessary first step, but much more needs to be done to improve clinical outcomes. In 2019, ischaemic heart disease was the third leading cause of death in Gambian women and the fourth leading cause of death in men, whereas stroke ranked as the fifth and sixth top cause of death in Gambian women and men, respectively.6WHOHealth data overview for Republic of the Gambia.https://data.who.int/countries/270Date accessed: November 14, 2023Google Scholar These figures reflect not only the high prevalence of risk factors, but also the inadequate ability of the health-care system to appropriately manage individuals with major cardiovascular events in many parts of the subcontinent. A 10-year systematic review of patients presenting with acute coronary syndromes in sub-Saharan Africa reported in-hospital mortality ranging from 1·2% to 24 ·5%, and 30 day mortality between 7·8% and 43·3%, with higher mortality in lower-income settings.7Yao H Ekou A Niamkey T et al.Acute coronary syndromes in sub-Saharan Africa: a 10-year systematic review.J Am Heart Assoc. 2022; 11e021107 Crossref Scopus (10) Google Scholar 1-month pooled case fatality rate from stroke in the subcontinent has been estimated at 24·1%, increasing to 33·2% at one year,8Adoukonou T Kossi O Mefo PF et al.Stroke case fatality in sub-Saharan Africa: systematic review and meta-analysis.Int J Stroke. 2021; 16: 902-916Crossref PubMed Scopus (30) Google Scholar highlighting that mortality is high even in those who access health care. The study1Jobe M Mactaggart I Bell S et al.Prevalence of hypertension, diabetes, obesity, multimorbidity, and related risk factors among adult Gambians: a cross-sectional nationwide study.Lancet Glob Health. 2024; 12: e54-e65Google Scholar emphasises that chronic NCDs should now be squarely on the agenda of lower-income countries in sub-Saharan Africa. Although further research is necessary, policy makers should not use this as an excuse to delay implementing measures to improve outcomes now. Economic realities preclude significant investment in tertiary health facilities, and focus should therefore be placed on restructuring social and health systems to target primordial and primary prevention along the life course, particularly since there is a high prevalence of some NCDs at younger ages. Targeted screening programmes should be introduced for individuals at highest disease risk, and once diagnosed, monitoring and evaluation needs to be robust to ensure that individuals are achieving therapeutic targets. Interventions must be context-specific and take advantage of existing health infrastructure and social factors, such as community health worker programmes and mobile telephone penetration, to decentralise care and improve accessibility. Although the cost of implementing health-care reforms to address NCDs in lower-income countries in sub-Saharan Africa might seem daunting in the face of multiple competing priorities, the cost of inaction will be far higher. ANW reports receiving an honorarium from Sanofi for serving as a panel member at an educational event on thyroid cancer and support from Novo Nordisk to attend a continuing medical education event. ANW is supported by the Fogarty International Centre, US National Institutes of Health under award number K43TW010698. Prevalence of hypertension, diabetes, obesity, multimorbidity, and related risk factors among adult Gambians: a cross-sectional nationwide studyWe have documented high levels of NCDs and associated risk factors in Gambian adults. This presents a major stress on the country's fragile health system that requires an urgent, concerted, and targeted mutisectoral strategy. Full-Text PDF Open Access