Black African Population Research Articles

Comorbidities in Nigerian patients with rheumatoid arthritis.

Rheumatoid arthritis has been infrequently reported among African black populations. Recent data have shown increasing reportage. Comorbidities are increasingly recognised as important in the overall morbidity, mortality and response to management. There have been few reports from Africa on the frequency and role of comorbidities associated with rheumatoid arthritis (RA) in Africans. This 20-year retrospective study looked at the frequency of various comorbidities among Nigerian patients with rheumatoid arthritis from a rheumatology facility. Data were obtained from the case record files of 283 RA patients. The chi-square test was used to assess the relationship between patient characteristics and the presence of comorbidity, while logistic regression was used to determine factors that were independently associated with the occurrence of comorbidities in these patients. The frequency of comorbidities among RA patients is high at 52.3%, mainly from common conditions such as hypertension (22.3%), dyslipidaemia (11.3%), osteoarthritis (8.1%), diabetes mellitus (7.1%), peptic ulcer disease (6.4%) and interstitial lung disease (3.5%). Increasing age (χ2 47.74, P<0.001) and prolonged duration of symptoms before diagnosis (χ2 9.0, P = 0.02) were significantly associated with the presence of comorbidity on univariate analysis, and only age was found to be independently associated with comorbidities on logistic regression. The frequencies of these comorbidities are similar in certain aspects to other such reports but differ from others. An important factor may be the delay in presentation to a rheumatologist. It is hoped that other more extensive studies will elucidate some of these findings.

A statistical shape model for estimating missing soft tissues of the face in a black South African population.

Facial disfigurement may affect the quality of life of many patients. Facial prostheses are often used as an adjuvant to surgical intervention and may sometimes be the only viable treatment option. Traditional methods for designing soft-tissue facial prostheses are time-consuming and subjective, while existing digital techniques are based on mirroring of contralateral features of the patient, or the use of existing feature templates/models that may not be readily available. We aim to support the objective and semi-automated design of facial prostheses with primary application to midline or bilateral defect restoration where no contralateral features are present. Specifically, we developed and validated a statistical shape model (SSM) for estimating the shape of missing facial soft tissue segments, from any intact parts of the face. An SSM of 3D facial variations was built from meshes extracted from computed tomography and cone beam computed tomography images of a black South African sample (n = 235) without facial disfigurement. Various types of facial defects were simulated, and the missing parts were estimated automatically by a weighted fit of each mesh to the SSM. The estimated regions were compared to the original regions using color maps and root-mean-square (RMS) distances. Root mean square errors (RMSE) for defect estimations of one orbit, partial nose, cheek, and lip were all below 1.71mm. Errors for the full nose, bi-orbital defects, as well as small and large composite defects were between 2.10 and 2.58mm. Statistically significant associations of age and type of defect with RMSE were observed, but not with sex or imaging modality. This method can support the objective and semi-automated design of facial prostheses, specifically for defects in the midline, crossing the midline or bilateral defects, by facilitating time-consuming and skill-dependent aspects of prosthesis design.

Analytical validation of GenoPharm a clinical genotyping open array panel of 46 pharmacogenes inclusive of variants unique to people of African ancestry.

Pharmacogenomic testing may be used to improve treatment outcomes and reduce the frequency of adverse drug reactions (ADRs). Population specific, targeted pharmacogenetics (PGx) panel-based testing methods enable sensitive, accurate and economical implementation of precision medicine. We evaluated the analytical performance of the GenoPharm® custom open array platform which evaluates 120 SNPs across 46 pharmacogenes. Using commercially available reference samples (Coriell Biorepository) and in-house extracted DNA, we assessed accuracy, precision, and linearity of GenoPharm®. We then used GenoPharm® on 218 samples from two Southern African black populations and determined allele and genotype frequencies for selected actionable variants. Across all assays, the GenoPharm® panel demonstrated 99.5% concordance with the Coriell reference samples, with 98.9% reproducibility. We observed high frequencies of key genetic variants in people of African ancestry: CYP2B6*6 (0.35), CYP2C9*8, *11 (0.13, 0.03), CYP2D6*17 (0.21) and *29 (0.11). GenoPharm® open array is therefore an accurate, reproducible and sensitive test that can be used for clinical pharmacogenetic testing and is inclusive of variants specific to the people of African ancestry.

The Impact of Certain Pharmacogenetic Differences on the Metabolism of Antiretroviral Drugs Used in A Black South African Population.

Genetic polymorphism of drug-metabolising enzymes and transporters may influence the effect and toxicity of antiretroviral drugs. To determine and compare the minimum allele frequency of 20 single nucleotide polymorphisms (SNPs) with possible involvement in the metabolism of the antiretroviral drugs with other populations. To investigate the influence of these variants on Reverse transcriptase, Protease and Integrase strand transfer inhibitor drugs. DNA samples were collected from 1489 subjects. All SNPs with a gene call score of > 0.6 were selected for genotyping. The R package calculated call rates, MAF and Hardy-Weinberg equilibrium (HWE), test p-values, and Chi-squared analysis were performed on the data. The Fisher's exact test compared the allele frequencies between the populations. The highest similarities in minimum allele frequency (MAF) were between the Prospective Urban and Rural Epidemiological group (PURE), a Black population in South Africa, and the Yoruba and Luhya populations in Africa. The following SNPs were identified with a possible effect on metabolism: CYP2B6 rs28399494 (MAF 11%) is indicated in the toxicity of Efavirenz and Nevirapine. CYP3A5 rs776746 (MAF 17%) and CYP3A4 rs2749674 (MAF 23%) both cause an increase in the metabolism of the protease inhibitors. The very low MAF values for both SCL01B1 rs4149056 (MAF 0.6%) and ABCC rs717620 (MAF 2.8%) are indications that OATP1B1 transport function and glomerular filtration tempo will not be compromised. The high MAF value of 30% for UGTA1 rs10929302 can result in hyperbilirubinemia, which can decrease the clearance of Dolutegravir. These results show a possibility of kidney protection and an increase in bilirubin in this population.

Which side are they on? Diagnosing primary ciliary dyskinesias in low- or middle-income countries: A review and case series.

Primary ciliary dyskinesia (PCD) is a rare genetic condition with a variable clinical presentation, making its diagnosis a challenge. We describe two unrelated sibling pairs with PCD: adult siblings in the first and perinatal/neonatal in the second. Both families highlight the more common and rarer clinical manifestations of PCD. We use these cases to highlight: (i) current understanding of the underlying genetic and pathophysiological mechanisms of PCD; (ii) the diversity of cardiac and respiratory features of PCD across a wide age range; (iii) aspects of the history and clinical examination that should raise suspicion of PCD; and (iv) the role of next-generation sequencing gene panel testing in confirmation of the diagnosis. We note genomic evidence predicting that PCD is relatively common in black African populations. What the study adds. This review of two sibling pairs illustrates the variable histories, presentations, diagnostic processes and clinical courses of primary ciliary dyskinesia (PCD) in low- or middle-income countries (LMICs), highlighting the diagnostic challenges faced when encountering such patients in settings where there may not be access to specialised resources. Possible diagnostic tools that can be used are discussed, weighing up their pros and cons in an LMIC setting, and a potential diagnostic approach that can be adapted to the treating clinician's own context is provided.Implications of the findings. Confirmation of the diagnosis of primary ciliary dyskinesia is no longer limited to well-resourced institutions, but can be done in less specialised environments using novel, highly accurate next-generation sequencing gene panel testing, reducing the need to transport patients as well as the overall cost to the healthcare system. Well-resourced institutions that see high volumes of patients with PCD can invest in new highly sensitive diagnostic tools such as high-speed video microscopy. There is a need for research investigating the validity of tools such as ciliary immunofluorescence in the South African population.

Variation in Termination of Brachial Artery Among Black African Population

Variation in Termination of Brachial Artery Among Black African Population

Variations in the origin of the coronary artery in black African population: a cadaveric study in western Kenya

Background: The coronary arteries which originate from the right and left aortic orifices are the main blood vessels to the myocardium. Variations are anomalies which could affect the overall perfusion of the myocardium causing conditions like ischemic heart diseases leading to sudden unpredicted death. Variants can also cause confusion to cardiologists and heart surgeons leading to challenges in patient management. This study sought to determine these variations among black African population in Western Kenya by assessing the variations in origin of the coronary artery. Methods: A cross-sectional study design was used in the Maseno University, Uzima University and Masinde Muliro University Human anatomy laboratories. Out of a total of 89 cadavers,72 samples were identified using Cochran’s formula. Data sheets were used to capture the variables while descriptive statistics was used to calculate the frequency and percentage of the variation in the origin of the coronary arteries while Pearson’s correlation test was used to analyze the relationship between the variables and variations P=≤ 0.05 considered as significant. All ethical approval was issued via license number: NACOSTI /P/22/21905.Results: Dual aortic origin was the most common occurrence at 55.6% while 44.4% were variations with more than one orifice on the aortic cusps. Conclusions: There were variations which could be fatal during surgical procedures, but also important alternate pathway for the perfusion of the myocardium. There is need for early routine imaging of the heart for effective management and to avoid mortalities and morbidity associated with the variations.

Anatomical variations in morphology of right and left brachial plexus among black African population; a cadaveric study in western Kenya

Background: Brachial plexus (Bp) is a network of bundles of nerves of spinal cord around neck and axilla in the body formed by union of anterior primary rami of C5 to C8, and T1. Technical expertise required for clinical and surgical procedures remains challenging for the beginners. Variations may be due to trauma, irradiation, neoplasm, infection, and autoimmune inflammatory disease. The purpose of this study was to determine the difference in variation of right and left Bp of the study population. Methods: Cross sectional descriptive study was used in Maseno, Uzima and Masinde Muliro Universities anatomy laboratory to get sample size of 35male and 35 female cadavers. Chi- square test was set at a p= 0.05. Ethical consideration was observed. Results: Statistically significant difference (p=0.009) between the right and the left upper limb in the branching of musculocutaneous nerve was recorded. A total of 17.8% variations in origin and segments of Bp, majority 9.9% were from left while 7.9% from right. Highest frequency of variation occurred at the prefixed root of Bp with 8.7% occurring on left upper limb and 12.13% on right upper limb. Right upper limbs had highest incidence of variations in branching patterns of Bp at 43% whilst left had incidence of 23.5%. Highest frequency of main terminal variation was of musculocutaneous nerve at 18.6% with 13.6% occurring on right side and 5% on left side. Conclusion: Knowledge of variations is essential in evaluation of unexplained sensory and motor loss after trauma and surgical interventions to the upper limb.

Hard tissue characteristics of patients with bimaxillary protrusion

Bimaxillary protrusion (BP) is a common developmental condition amongst the South African Black population characterized by proclined incisors with resultant procumbency of the lips. The aim of this study was to perform a cephalometric radiographic analysis of the pre-treatment dental and skeletal structures in a sample of Black South Africans in order to identify the characteristic features of BP in this race group and compare them to norms. Records of 67 South African Black patients divided into 28 males and 39 females with a mean age of 17.8 years, clinically diagnosed with BP were included in the study. Cephalometric parameters were hand traced on lateral cephalometric radiographs and measurements recorded for evaluation and comparison to norm values used for this population group to determine the features that both males and females present with. Characteristic pre-treatment dental features of the sample included maxillary incisors that were proclined and protruded with resultant decreased interincisal angle, mandibular incisors which were favourably positioned. Skeletal features included retrognathic jaws (maxilla to a greater degree) resulting in a mild to moderate Class III skeletal pattern but with females exhibiting a smaller ANB angle indicating a greater tendency for a Class III skeletal pattern. The skeletal growth pattern was vertically directed with an average anterior facial height ratio. The findings indicate that most BP patients in this South African Black population presented with dentoalveolar protrusion, retrognathic jaws and a mild to moderate skeletal Class III pattern

Evaluation of the Three Main Estimated Glomerular Filtration Rate (eGFR) Equations in a Black African Population: A Cross-Sectional Study among Type 2 Diabetes Patients in Ghana

Evaluation of the Three Main Estimated Glomerular Filtration Rate (eGFR) Equations in a Black African Population: A Cross-Sectional Study among Type 2 Diabetes Patients in Ghana

Effects of Genetic Polymorphisms of Drug Metabolizing Enzymes and co-Medications on Tamoxifen Metabolism in Black South African Women with Breast Cancer.

Clinical outcomes of tamoxifen (TAM) treatment show wide interindividual variability. Comedications and genetic polymorphisms of enzymes involved in TAM metabolism contributes to this variability. Drug-drug and drug-gene interactions have seldom been studied in African Black populations. We evaluated the effects of commonly co-administered medicines on TAM pharmacokinetics in a cohort of 229 South African Black female patients with hormone-receptor positive breast cancer. We also investigated the pharmacokinetic effects of genetic polymorphism in enzymes involved in TAM metabolism, including the variants CYP2D6*17 and *29, which have been mainly reported in people of African descent. TAM and its major metabolites, N-desmethyltamoxifen (NDM), 4-OH-tamoxifen, and endoxifen (ENDO), were quantified in plasma using the liquid chromatography-mass spectrometry. The GenoPharm open array was used to genotype CYP2D6, CYP3A5, CYP3A4, CYP2B6, CYP2C9, and CYP2C19. Results showed that CYP2D6 diplotype and CYP2D6 phenotype significantly affected endoxifen concentration (P < 0.001 and P < 0.001). CYP2D6*17 and CYP2D6*29 significantly reduced the metabolism of NDM to ENDO. Antiretroviral therapy had a significant effect on NDM levels and the TAM/NDM and NDM/ENDO metabolic ratios but did not result in significant effects on ENDO levels. In conclusion, CYP2D6 polymorphisms affected endoxifen concentration and the variants CYP2D6*17 and CYP2D6*29 significantly contributed to low exposure levels of ENDO. This study also suggests a low risk of drug-drug interaction in patients with breast cancer on TAM.

Prostrate malignant tumor and benign prostatic hyperplasia microenvironments in black African men: Limited infiltration of CD8+ T lymphocytes, NK-cells, and high frequency of CD73+ stromal cells.

Anti-cancerous immunology has yet to be investigated in the African black population, despite being the dawn of precision medicine. Here we investigated the tumor microenvironment of prostate cancer and benign prostatic hyperplasia (BPH) in black Africans. Through immunohistochemistry analysis of prostate cancer and BPH patients' biopsies, we investigated the expression and distribution of CD73, CCD8 T-lymphocytes, and natural killer cells. In addition, we looked at tumor-infiltrating features CD8 T-lymphocytes and natural killer cells. We show for the first time in black Africans a high expression of CD73 in epithelial-stromal cells and virtually no infiltration of CD8 T lymphocytes and natural killer cells in the tumoral area. In addition, CD73 was seven (7) times more likely to be expressed in prostate cancer stromal tissues than in benign prostatic hyperplasia tissues (odds ratio = 7.2; χ2 = 21; p < .0001). In addition, PSA concentration was significantly higher in prostate cancer patients than in BPH patients (p < .001). Also, the PSA-based ROC. analysis showed an area under the curve of 0.87 (p < .0001). CD73 expression is more likely expressed in prostate cancer stromal tissues than in benign prostatic hyperplasia tissues. The features of prostate cancer in Black Africans suggest CD73 expression as a possible target for immunotherapy in this population.

New and old GFR equations: a European perspective.

Glomerular filtration rate (GFR) is estimated in clinical practice from equations based on the serum concentration of endogenous biomarkers and demographic data. The 2009 creatinine-based Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI2009) was recommended worldwide until 2021, when it was recalibrated to remove the African-American race factor. The CKD-EPI2009 and CKD-EPIcr2021 equations overestimate GFR of adults aged 18-30 years, with a strong overestimation in estimated GFR (eGFR) at age 18 years. CKD-EPICr2021 does not perform better than CKD-EPI2009 in US population, overestimating GFR in non-Black subjects, and underestimating it in Black subjects with the same magnitude. CKD-EPICr2021 performed worse than the CKD-EPI2009 in White Europeans, and provides no or limited performance gains in Black European and Black African populations. The European Kidney Function Consortium (EKFC) equation, which incorporates median normal value of serum creatinine in healthy population, overcomes the limitations of the CKD-EPI equations: it provides a continuity of eGFR at the transition between pediatric and adult care, and performs reasonably well in diverse populations, assuming dedicated scaling of serum creatinine (Q) values is used. The new EKFC equation based on cystatin C (EKFCCC) shares the same mathematical construction, namely, it incorporates the median cystatin C value in the general population, which is independent of sex and ethnicity. EKFCCC is therefore a sex-free and race-free equation, which performs better than the CKD-EPI equation based on cystatin C. Despite advances in the field of GFR estimation, no equation is perfectly accurate, and GFR measurement by exogenous tracer clearance is still required in specific populations and/or specific clinical situations.

Physical and psychosocial aspects of healthy ageing and HIV status among older adults in South Africa

The study aimed to assess the prevalence by type of psychosocial associations with healthy ageing among older adults by HIV status in South Africa. We analysed data from the 2017 South African National HIV Prevalence, Incidence, Behaviour, and Communication Survey. This was a national cross-sectional household survey, including 7 596 older adults (≥ 50 years, median age = 60 years). Results indicated that the prevalence of healthy ageing was 25.9%, 19.9% among HIV-positive and 26.8% among HIV-negative persons. Of the participants, 49.1% self-reported no major disease and 93.0% reported no disability. Furthermore, 63.9% of the participants reported to be in good mental health, and 65.9% reported good overall health. Male sex and higher education were positively associated. Further, an HIV-positive status, older age, widowed, African black population group, and urban residence were negatively associated with overall healthy ageing. The study found a lower prevalence of healthy ageing among older persons with HIV compared to persons without HIV, which was associated with poorer mental health self-perceptions among those living with HIV.

Individual and area-level socioeconomic correlates of hypertension prevalence, awareness, treatment, and control in uMgungundlovu, KwaZulu-Natal, South Africa

BackgroundHypertension is the second leading risk factor for death in South Africa, and rates have steadily increased since the end of Apartheid. Research on the determinants of hypertension in South Africa has received considerable attention due to South Africa’s rapid urbanization and epidemiological transition. However, scant work has been conducted to investigate how various segments of the Black South African population experience this transition. Identifying the correlates of hypertension in this population is critical to the development of policies and targeted interventions to strengthen equitable public health efforts.MethodsThis analysis explores the relationship between individual and area-level socioeconomic status and hypertension prevalence, awareness, treatment, and control within a sample of 7,303 Black South Africans in three municipalities of the uMgungundlovu district in KwaZulu-Natal province: the Msunduzi, uMshwathi, and Mkhambathini. Cross-sectional data were collected on participants from February 2017 to February 2018. Individual-level socioeconomic status was measured by employment status and educational attainment. Ward-level area deprivation was operationalized by the most recent (2011 and 2001) South African Multidimensional Poverty Index scores. Covariates included age, sex, BMI, and diabetes diagnosis.ResultsThe prevalence of hypertension in the sample was 44.4% (n = 3,240). Of those, 2,324 were aware of their diagnosis, 1,928 were receiving treatment, and 1,051 had their hypertension controlled. Educational attainment was negatively associated with hypertension prevalence and positively associated with its control. Employment status was negatively associated with hypertension control. Black South Africans living in more deprived wards had higher odds of being hypertensive and lower odds of having their hypertension controlled. Those residing in wards that became more deprived from 2001 to 2011 had higher odds of being aware of their hypertension, yet lower odds of receiving treatment for it.ConclusionsResults from this study can assist policymakers and practitioners in identifying groups within the Black South African population that should be prioritized for public health interventions. Black South Africans who have and continue to face barriers to care, including those with low educational attainment or living in deprived wards had worse hypertension outcomes. Potential interventions include community-based programs that deliver medication to households, workplaces, or community centers.

Frames of war and welfare

Frames of war and welfare

A review of spinal muscular atrophy in black South African paediatric patients

Background. Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder that is present in all populations andresults in muscle weakness owing to anterior horn cell degeneration. SMA is divided into three clinical subtypes and is an importantgenetic cause of morbidity and mortality but has not been well studied in sub-Saharan Africa.Objective. This study aims to describe the clinical features and genetic findings in black patients with SMA presenting to the Division ofPaediatric Neurology at Chris Hani Baragwanath Academic Hospital (CHBAH) over a 30-year period.Method. This study was a retrospective review of patient records. The study population was black paediatric neurology patients withclinical SMA, who attended CHBAH Neurology Clinic between 1988 and 2018. Patients were categorised into SMA type 1, 2 or 3 basedon their neurology assessment and clinical features were recorded.Results. The clinical findings in the study population (with SMA), i.e. hypotonia, areflexia and tongue fasciculations, were similar to those found in international studies. More than half of the patients (65.6%; n=86/131) had genetic tests, of which 84.8% were positive for SMA. This value was significantly higher than previously reported results from South Africa. At least 23.6% (n=31/131) had facial involvement.Conclusions. This study adds to the limited body of research on SMA in sub-Saharan Africa and highlights the lower frequency of ahomozygous deletion seen in the black South African population compared with the expected 95% worldwide.

Investigation of mandibular second molar root and canal morphology in a Black South African population using cone-beam computed tomography and two classification systems.

To investigate the root and canal morphology of mandibular second molars, including anatomical variations, in a Black South African population using two classification systems. Cone-beam computed tomography images of 386 teeth were evaluated. The number of roots and canal configurations were categorized using the classifications of Vertucci (with modifications by Sert and Bayirli) and Ahmed et al. (including the modified Melton classification). Relationships between variables were assessed using Fisher's exact test (P < 0.05). Mandibular second molars were predominantly two-rooted (91.7%). The majority of teeth had three canals including Type IV mesial (41.2%) and Type I (75.1%) distal (Ahmed et al. configuration: 2MDM M2 D1). Three or more canals were present in almost one-fifth of mesial (n = 72/386, 18.6%) and a small number of distal (n = 21/386, 5.4%) roots. Males displayed additional canals more frequently in the distal root (P = 0.02). C-shaped anatomy was found in 5.7%. Among the C-shapes, the most common was Melton's Type III in the coronal (50%), middle (81%) and apical (72%) thirds. In this population, mandibular second molar teeth exhibited diverse morphology, which would have clinical significance for endodontic practitioners. The Ahmed et al. classification provided a better description than the Vertucci classification.

Porphyric neuropathy in black South Africans: a case series

Abstract Porphyria is a rare disorder that results from mutations in the genes important in haem biosynthesis. Several types are described. Acute attacks lead to central, autonomic and peripheral nervous system manifestations. These acute attacks typically occur in acute intermittent porphyria, and less so in variegate porphyria. The neuropathy in this condition can mimic Guillain-Barré syndrome (GBS), and is often misdiagnosed and incorrectly treated. It is rare in general, but considered to be extremely uncommon in the black African population. We describe five black South African patients, three of whom were diagnosed with variegate porphyria, with the presenting manifestation of a severe neuropathy. The neuropathy was atypical in nature and variable in presentation and highlight the importance of considering porphyria in such patients.

Laparoscopic Myomectomy for Huge Uterine Fibroid in Sub-Saharan Africa: A Case Report

Abstract The prevalence of extensive and multiple uterine fibroids among the Black African population is a significant concern, as it limits the available management options. The focus on girl child education and improvement in women empowerment have contributed to an increased demand for less invasive options in the management of uterine fibroids. This trend aims to improve cosmesis and, more importantly, facilitate an early return to work and normal activity. In sub-Saharan Africa, the available management options for uterine fibroids have primarily been limited to abdominal myomectomy and hysterectomy. However, anecdotal reports indicate the use of less invasive management options such as uterine artery embolization, laparoscopic radiofrequency ablation, and laparoscopic myomectomy. These interventions are reserved for small- and medium-sized fibroids, with the largest being &lt;15 cm and usually not more than five myoma nodules. We present a case report of laparoscopic myomectomy for a huge uterine fibroid weighing 2.4 kg in a nulliparous patient. In well-selected, properly evaluated patients with large subserous uterine fibroids, laparoscopic myomectomy emerges as a viable option that could be offered as an armamentarium in the management of huge fibroids, particularly in sub-Saharan Africa.