The genetic legacy of the expansion of Bantu-speaking peoples in Africa.

The expansion of people speaking Bantu languages is the most dramatic demographic event in Late Holocene Africa and fundamentally reshaped the linguistic, cultural and biological landscape of the continent1-7. With a comprehensive genomic dataset, including newly generated data of modern-day and ancient DNA from previously unsampled regions in Africa, we contribute insights into this expansion that started 6,000-4,000 years ago in western Africa. We genotyped 1,763 participants, including 1,526 Bantu speakers from 147 populations across 14 African countries, and generated whole-genome sequences from 12 Late Iron Age individuals8. We show that genetic diversity amongst Bantu-speaking populations declines with distance from western Africa, with current-day Zambia and the Democratic Republic of Congo as possible crossroads of interaction. Using spatially explicit methods9 and correlating genetic, linguistic and geographical data, we provide cross-disciplinary support for a serial-founder migration model. We further show that Bantu speakers received significant gene flow from local groups in regions they expanded into. Our genetic dataset provides an exhaustive modern-day African comparative dataset for ancient DNA studies10 and will be important to a wide range of disciplines from science and humanities, as well as to the medical sector studying human genetic variation and health in African and African-descendant populations.

Using Clinical Vignettes to Understand the Complexity of Diagnosing Type 1 Diabetes in Sub-Saharan Africa.

Lack of awareness, access to insulin and diabetes care can result in high levels of morbidity and mortality for children with type 1 diabetes (T1DM) in sub-Saharan Africa (SSA). Improvements in access to insulin and diabetes management have improved outcomes in some settings. However, many people still present in diabetic ketoacidosis (DKA) in parallel to misdiagnosis of children with T1DM in contexts with high rates of communicable diseases. The aim of this study was to highlight the complexity of diagnosing pediatric T1DM in a healthcare environment dominated by infectious diseases and lack of adequate health system resources. This was done by developing clinical vignettes and recreating the hypothetico-deductive process of a clinician confronted with DKA in the absence of identification of pathognomonic elements of diabetes and with limited diagnostic tools. A non-systematic literature search for T1DM and DKA in SSA was conducted and used to construct clinical vignettes for children presenting in DKA. A broad differential diagnosis of the main conditions present in SSA was made, then used to construct a clinician's medical reasoning, and anticipate the results of different actions on the diagnostic process. An examination of the use of the digital based Integrated Management of Childhood Illness diagnostic algorithm was done, and an analysis of the software's efficiency in adequately diagnosing DKA was assessed. The main obstacles to diagnosis were low specificity of non-pathognomonic DKA symptoms and lack of tools to measure blood or urine glucose. Avenues for improvement include awareness of T1DM symptomatology in communities and health systems, and greater availability of diagnostic tests. Through this work clinical vignettes are shown to be a useful tool in analyzing the obstacles to underdiagnosis of diabetes, a technique that could be used for other pathologies in limited settings, for clinical teaching, research, and advocacy.

Prevalence and influences of diabetes and prediabetes among adults living with HIV in Africa: a systematic review and meta-analysis.

INTRODUCTION: In people living with human immunodeficiency virus (PLHIV), traditional cardiovascular risk factors, exposure to HIV per se and antiretroviral therapy (ART) are assumed to contribute to cardiometabolic diseases. Nevertheless, controversy exists on the relationship of HIV and ART with diabetes. To clarify the relationship between HIV and type 2 diabetes, this review determined, in PLHIV in Africa, diabetes and prediabetes prevalence, and the extent to which their relationship was modified by socio-demographic characteristics, body mass index (BMI), diagnostic definitions used for diabetes and prediabetes, and HIV-related characteristics, including CD4 count, and use and duration of ART. METHODS: For this systematic review and meta-analysis (PROSPERO registration CRD42021231547), a comprehensive search of major databases (PubMed-MEDLINE, Scopus, Web of Science, Google Scholar and WHO Global Health Library) was conducted. Original research articles published between 2000 and 2021 in English and French were included, irrespective of study design, data collection techniques and diagnostic definitions used. Observational studies comprising at least 30 PLHIV and reporting on diabetes and/or prediabetes prevalence in Africa were included. Study-specific estimates were pooled using random effects models to generate the overall prevalence for each diagnostic definition. Data analyses used R statistical software and "meta" package. RESULTS: Of the 2614 records initially screened, 366 full-text articles were assessed for eligibility and 61 were selected. In the systematic review, all studies were cross-sectional by design and clinic-based, except for five population-based studies. Across studies included in the meta-analysis, the proportion of men was 16-84%. Mean/median age was 30-62 years. Among 86,412 and 7976 participants, diabetes and prediabetes prevalence rates were 5.1% (95% CI: 4.3-5.9) and 15.1% (9.7-21.5). Self-reported diabetes (3.5%) was lower than when combined with biochemical assessments (6.2%; 7.2%). DISCUSSION: While not statistically significant, diabetes and prediabetes were higher with greater BMI, in older participants, urban residents and more recent publications. Diabetes and prediabetes were not significantly different by HIV-related factors, including CD4 count and ART. CONCLUSIONS: Although HIV-related factors did not modify prevalence, the diabetes burden in African PLHIV was considerable with suboptimal detection, and likely influenced by traditional risk factors. Furthermore, high prediabetes prevalence foreshadows substantial increases in future diabetes in African PLHIV.

Association between severe acute malnutrition during childhood and blood pressure during adulthood in the eastern Democratic Republic of the Congo: the Lwiro cohort study.

INTRODUCTION: Little is known about the long-term outcomes of Severe Acute Malnutrition (SAM) during childhood. As such, this study aims to explore the association between childhood SAM and blood pressure (BP) in adulthood in a context without nutrition transition. METHODOLOGY: We identified 524 adults (Median age: 22 years) who were treated for SAM during childhood in Eastern DRC between 1988 and 2007. They were compared with 407 age-and-sex matched subjects with no history of SAM in the community. The variables examined for this study were the systolic (SBP), diastolic (DBP), mean (MBP) blood pressure (BP) and pulse pressure (PP), as well as high blood pressure (HBP) defined as BP ≥ 140/90 mmHg and/or use of BP-lowering drug(s) in adulthood. For comparison, linear and logistic regression models were used for analysing continuous and dichotomous variables, respectively. RESULTS: Of the 524 exposed located, 145 were selected according to age. A total of 97 unexposed were recruited. Compared to unexposed, exposed had slightly higher SBP and PP after adjusting for occupation, body mass index (BMI) and food consumption [SBP = 1.4 mmHg (- 2.2, 4.8) and PP = 2.6 mmHg (- 0.3, 6.0)]. However, their DBP was lower than that of the unexposed [- 1.6 mmHg (- 4.6, 1.5)]. MBP and creatinine levels were similar between the two groups. The prevalence of HBP adjusted for age was higher among exposed than unexposed (9.7% vs 5.3%). In addition, the odds of having HBP was higher among exposed than unexposed, however the observed difference was not statistically significant [Odds Ratio (OR) 1.9 (0.7, 5.6)]. Finally, using multiple regression analysis, although the effect was not significant, SAM was a major contributor to HBP [adjusted OR 3.1 (0.9,10.9), p = 0.064], while only male gender and higher BMI (overweight/obesity) emerged as independent predictors of HBP among this young study population. CONCLUSIONS: This study suggests that an episode of SAM in childhood has a weak impact on BP variability in young Congolese adults (from DRC) living in an environment without nutrition transition. However, people who experienced a period of SAM tended to have a higher prevalence of HBP and a much higher risk of developing HBP than unexposed. Additional multicentre studies involving a larger cohort would provide greater understanding of the impact of SAM on the overall risk of BP disorders during adulthood.

Atypical respiratory distress in eastern Democratic Republic of the Congo prior to the COVID-19 pandemic. A case report.

BACKGROUND: Predictions have been made that Africa would be the most vulnerable continent to the novel Coronavirus disease 2019 (COVID-19). Interestingly, the spread of the disease in Africa seems to have been delayed and initially slower than in many parts of the world. Here we report on two cases of respiratory distress in our region before the official declaration of the disease in December 2019, cases which in the present times would be suspect of COVID-19. CASE PRESENTATION: These two cases (one 55-year-old man and one 25-year-old woman) of acute respiratory distress secondary to atypical pneumonia were seen in Bukavu, in Eastern Democratic Republic of the Congo (DRC), between September and December 2019. One patient had returned from China and the other had close contacts with travellers from China in the 2 weeks prior to the onset of symptoms. In either case, the aetiology could not be accurately determined. However, the two cases presented a clinical picture (progressive dyspnoea, preceded by dry cough and fever) and laboratory changes (procalcitonin within the normal range, slight inflammation, and lymphopenia) compatible with a viral infection. The chest X-ray series of the first patient showed lesions (reticulations, ground glass, and nodules ≤6 mm) similar to those currently found in COVID-19 patients. In addition, unlike the 25-year-old female patient who had no comorbidity, the 55-year-old male patient who had hypertension as comorbidity, developed a more severe acute respiratory distress which progressed to death. CONCLUSION: These cases bring to the attention the fact that COVID-19-like syndromes may have already been present in the region months before the official beginning of the pandemic. This also brings to question whether a prior presence of the disease or infections with related virus may account for the delayed and less extensive development of the pandemic in the region.