High Diabetes Prevalence and Implications for Progress Toward SDG 3: An Umbrella Review of Four African Countries

Background: Diabetes mellitus (DM) is an emerging public health challenge in Africa, driven by rapid urbanisation, changing lifestyles and socio-economic transitions. As the global prevalence rises, evidence on the burden and determinants of DM across African countries remains fragmented and inconsistent. Objective: We aimed to synthesize evidence from existing systematic reviews and meta-analyses on the prevalence and determinants of diabetes mellitus across African populations, thereby informing targeted interventions and policy actions. Methods: This umbrella review followed the PRISMA guidelines and included systematic reviews and meta-analyses of studies, published up to December 2024, that reported on DM prevalence and/or risk factors for DM in adults across four African countries. The literature was retrieved from PubMed, Scopus, Web of Science and African Journals Online (AJOL). Quality assessment was conducted using the AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews, version 2) tool, and only moderate- to high-quality reviews were retained. Random-effects models were used to estimate the pooled prevalence and odds ratios (ORs), while heterogeneity, publication bias and sensitivity analyses were also conducted. Findings: Seven reviews were included, covering four countries: Ethiopia, South Africa, Nigeria and Ghana. The pooled prevalence of diabetes mellitus was 9.0% (95% CI: 6.0–12.0%), with significant heterogeneity (I2 = 99.8%). Among the determinants, only family history of DM (OR:5.11, 95% CI: 2.96–8.85), hypertension (OR: 2.52; 95% CI: 1.65–3.83), obesity (OR: 3.04; 95% CI: 1.92–4.82), physical inactivity (OR: 3.32; 95% CI: 1.99–5.54), smoking (OR: 2.59; 95% CI: 1.23–5.47), unhealthy diet (OR: 4.77; 95% CI: 1.73–13.18) and urban residence (OR: 5.81; 95%CI: 4.41–7.65), showed a statistically significant association. Sensitivity analysis confirmed the robustness of pooled prevalence, and no significant publication bias was detected. Conclusions: Diabetes mellitus prevalence in Africa is rising and approaching the global averages. The heterogeneity in risk factors underscores the need for localised, context-specific strategies.