Black South African Population Research Articles

Association between RS7903146, RS17817499, RS17782313, RS229616, RS1297034, RS699 and RS4646994 and cardiometabolic diseases in a black South African population

Association between RS7903146, RS17817499, RS17782313, RS229616, RS1297034, RS699 and RS4646994 and cardiometabolic diseases in a black South African population

Antibodies against high-risk human papillomavirus proteins as markers for noncervical HPV-related cancers in a Black South African population, according to HIV status.

Human papillomavirus (HPV) proteins may elicit antibody responses in the process toward HPV-related malignancy. However, HPV seroepidemiology in noncervical HPV-related cancers remains poorly understood, particularly in populations with a high prevalence of human immunodeficiency virus (HIV). Using a glutathione S-transferase-based multiplex serology assay, antibodies against E6, E7 and L1 proteins of HPV16 and HPV18 were measured in sera of 535 cases of noncervical HPV-related cancers (anal (n = 104), vulval (n = 211), vaginal (n = 49), penile (n = 37) and oropharyngeal (n = 134)) and 6651 non-infection-related cancer controls, from the Johannesburg Cancer Study that recruited Black South African with newly diagnosed cancer between 1995 and 2016. Logistic and Poisson regression models were used to calculate adjusted odds ratios (aOR) and prevalence ratios (aPR) and 95% confidence intervals (CI) in cases versus controls. HPV16 E6 was more strongly associated with noncervical HPV-related cancers than HPV16 L1 or E7, or HPV18 proteins: anal (females (HPV16 E6 aOR = 11.50;95%CI:6.0-22.2), males (aOR = 10.12;95%CI:4.9-20.8), vulval (aOR = 11.69;95%CI:7.9-17.2), vaginal (aOR = 10.26;95%CI:5.0-21), penile (aOR = 18.95;95%CI:8.9-40), and oropharyngeal (females (aOR = 8.95;95%CI:2.9-27.5), males (aOR = 3.49;95%CI:1.8-7.0)) cancers. HPV16-E6 seropositivity ranged from 24.0% to 35.1% in anal, vulval, vaginal and penile cancer but was significantly lower (11.2%) in oropharyngeal cancer. After adjustment for HIV, prevalence of which increased from 22.2% in 1995-2005 to 54.1% in 2010-2016, HPV16 E6 seropositivity increased by period of diagnosis (aPR for 2010-2016 vs. 1995-2006 = 1.84;95%CI:1.1-3.0). Assuming HPV16 E6 seroprevalence reflects HPV attributable fraction, the proportion of certain noncervical-HPV-related cancers caused by HPV is increasing over time in South Africa. This is expected to be driven by the increasing influence of HIV.

Effect of impaction on third molar development and age estimation – A study in a female black South African population

The impact of impaction on the development of third molars remains a subject of debate within the scientific literature, given the lack of consensus. Simultaneously, there has been a call for dental age estimation studies to consider population-specific factors. This research was conducted with the objective of examining the influence of impaction on the formation of third molars in a cohort of female individuals of black South African descent. The study population comprised 428 panoramic radiographs, focusing on females within the age range of 15 to 23.9 years. Within this sample, mandibular third molars were categorized based on their positioning into two groups: non-impacted and impacted. Dental development stages were assessed and classified according to Demirjian’s 8-level staging system. Descriptive statistics were performed. The outcomes of the independent t-test revealed statistically significant differences in developmental stages, specifically stage G for tooth #38 and stage F for tooth #48, suggesting that impaction had an impact on dental development, albeit not consistently across all developmental stages. Nonetheless, it's noteworthy that the minimum and mean ages across all developmental stages were higher among impacted teeth. In summary, our findings support the conclusion that mineralization of impacted mandibular third molars in South African female subjects proceeds at a slower pace compared to their non-impacted counterparts. Consequently, when estimating dental age in the context of South African females, it is advisable to prioritize non-impacted third molars whenever feasible.

Cranial measurements obtained by three-dimensional computed tomography technique in the estimation of sex of contemporary Black South Africans

Human identification forms an integral part of forensic and biological anthropology. For proper identification, a biological profile made up of biodata such as age, sex, ancestry, antemortem stature, and factors of individualization, is obtained and stored for use by anthropologists. A correct sex estimation can help unravel other anthropological parameters. South Africa has a multi-dimensionally high crime rate and its largest distinct population group (Black South Africans) is most affected by such crimes. Several authors have in the past used cranial measurements to carry out sex discrimination among South Africans, such attempts have largely been done using direct assessment of post-mortem specimens and on subjects of European Descent. This study, therefore, attempted to overcome these drawbacks by using a non-invasive method, the three-dimensional computed tomography (3DCT) to obtain population-specific data from a contemporary Black South African population group. It obtained measurements from cranial CT records of 350 Black South Africans (50 % sex ratio) housed in the Radiology Department of Charlotte Maxeke Johannesburg Academic Hospital. The Xiris and IntelliSpace software were used to reconstruct the images into three-dimensional forms from which measurements were taken. Evaluation of previously derived equations using data from the current study yielded low average classification accuracies which necessitated the formulation of new equations. Discriminant function analysis yielded acceptably high average classification accuracies for sex estimation which ranged from 78.3 % to 82.9 %.

Three-dimensional volumetric analyses of temporal bone pneumatization from early childhood to early adulthood in a South African population.

A debate exists on whether the size of temporal bone pneumatization is a cause or consequence of otitis media (a global disease burden). However, a normal middle-ear mucosa is a prerequisite for normal temporal bone pneumatization. This study investigated the size of temporal bone pneumatization with age and the normal distribution of air cell volume in different stages of human growth postnatally. A three-dimensional computer-based volumetric-rendering technique was performed bilaterally on 248 head/brain and internal acoustic meatus computed tomography images of slice thickness ≤ 0.6 mm consisting of 133 males and 115 females with age range 0-35 years. The average volume of infant (0-2 years) pneumatization was 1920 mm3 with an expected rapid increase to about 4510 mm3 in childhood (6-9 years). The result also showed a significant increase (p < 0.001) in the volume of air cells up to the young adult stage I (19-25 years), followed by a significant decline in young adult stage II (26-35 years). However, the females were observed to experience an earlier increase than males. Also, population differences were observed as the Black South African population group showed a higher increase in volume with age than the White and Indian South African population groups, though the volumes of the latter increased up to young adult stage II. This study concludes that the pneumatization of a healthy temporal bone is expected to continue a linear increase up until at least adult stage I. Termination of temporal bone pneumatization in an individual before this stage could signify pathologic involvement of the middle ear during childhood.

Area-level deprivation and individual-level socioeconomic correlates of the diabetes care cascade among black south africans in uMgungundlovu, KwaZulu-Natal, South Africa.

South Africa is experiencing a rapidly growing diabetes epidemic that threatens its healthcare system. Research on the determinants of diabetes in South Africa receives considerable attention due to the lifestyle changes accompanying South Africa's rapid urbanization since the fall of Apartheid. However, few studies have investigated how segments of the Black South African population, who continue to endure Apartheid's institutional discriminatory legacy, experience this transition. This paper explores the association between individual and area-level socioeconomic status and diabetes prevalence, awareness, treatment, and control within a sample of Black South Africans aged 45 years or older in three municipalities in KwaZulu-Natal. Cross-sectional data were collected on 3,685 participants from February 2017 to February 2018. Individual-level socioeconomic status was assessed with employment status and educational attainment. Area-level deprivation was measured using the most recent South African Multidimensional Poverty Index scores. Covariates included age, sex, BMI, and hypertension diagnosis. The prevalence of diabetes was 23% (n = 830). Of those, 769 were aware of their diagnosis, 629 were receiving treatment, and 404 had their diabetes controlled. Compared to those with no formal education, Black South Africans with some high school education had increased diabetes prevalence, and those who had completed high school had lower prevalence of treatment receipt. Employment status was negatively associated with diabetes prevalence. Black South Africans living in more deprived wards had lower diabetes prevalence, and those residing in wards that became more deprived from 2001 to 2011 had a higher prevalence diabetes, as well as diabetic control. Results from this study can assist policymakers and practitioners in identifying modifiable risk factors for diabetes among Black South Africans to intervene on. Potential community-based interventions include those focused on patient empowerment and linkages to care. Such interventions should act in concert with policy changes, such as expanding the existing sugar-sweetened beverage tax.

Lewis a-b- histo-blood group antigen phenotype is predictive of severe COVID-19 in the black South African population group.

Several risk factors have been associated with SARS-CoV-2 infections and severity of COVID-19 disease it causes. This study investigated whether variations in histo-blood group antigen (HBGA) expression can predispose individuals to SARS-CoV-2 infections and severity of the disease. Nasopharyngeal swabs, randomly selected from SARS-CoV-2 positive and SARS-CoV-2 negative individuals, were tested for Lewis and H-type 1 HBGA phenotypes by ELISA using monoclonal antibodies specific to Lewis a, Lewis b and H type 1 antigens. The most common Lewis HBGA phenotype among all study participants was Lewis a-b+ (46%), followed by Lewis a-b- (24%), Lewis a+b- and Lewis a+b+ (15% each), while 55% of the study participants were H-type 1. Although SARS-CoV-2 negative individuals had a lower likelihood of having a Lewis a-b- phenotype compared to their SARS-CoV-2 positives counterparts (OR: 0.53, 95% C.I: 0.255-1.113), it did not reach statistical significance (P=0.055). The frequency of Lewis a+b+, Lewis a+B-, Lewis a-b+, H type 1 positive and H type 1 negative were consistent between SARS-CoV-2 positive and SARS-CoV-2 negative individuals. When stratified according to severity of the disease, individuals with Lewis a+b- phenotype had a higher likelihood of developing mild COVID-19 symptoms (OR: 3.27, 95% CI; 0.9604-11.1), but was not statistically significant (P=0.055), while Lewis a-b- phenotype was predictive of severe COVID-19 symptoms (OR: 4.3, 95% CI: 1.274-14.81), P=0.016. In conclusion, individuals with Lewis a-b- phenotype were less likely to be infected by SARS-CoV-2, but when infected, they were at risk of severe COVID-19.

Sex and age estimation utilizing the Mastoid, Bi-mastoid and Occipital triangles from three dimensional reconstructed models in subadults of a South African (KZN) Black population

The mastoid, bi-mastoid and occipital triangles at the base of the skull are known to be good indicators of sexual dimorphism. However, few studies assess age and sex in the subadult group. Therefore, the aim was to determine the age and sex of the human crania from a South African (KZN) Black population utilizing the triangles of the base of the skull of individuals between 0 and 18 years. The sample consisted of 64 computed tomography (CT) scans (32 male and 32 female) between 0 and 18 years of age. Three-dimensional reconstructed images and CT images were analysed using SLICER 3D. The following linear parameters were measured: the mastoidale - porion; porion - asterion; mastoidale - asterion; left mastoidale - opisthion; right mastoidale - opisthion; right mastoidale - left mastoidale; left asterion - lambda; right asterion - lambda; left asterion - right asterion. The study found that the mastoid, bi-mastoid and occipital triangles are good indicators for sexual dimorphism between the ages of 0–18 years. However, the mean values of the total area were higher in males than females. When comparing laterality, the right side of the mastoid triangle was more significant than the left (p-value=0.016), with the length of the mastoidale-porion being the only significant linear measurement. Results show that the linear measurement mastoidale-porion is highly correlated to age, with mean values of r = 0.87 and 0.88 for the left and right sides, respectively. Age is a confounding factor in sexual dimorphism. Additionally, the mastoid triangle is more accurate in age estimation.

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.

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.

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

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.

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.

Root and canal morphology of maxillary second molars in a Black South African subpopulation using cone-beam computed tomography and two classifications.

This study investigated the root and canal morphology of maxillary second molars in a Black South African population using high-resolution cone-beam computed tomography. In total, 386 maxillary second molar teeth were evaluated and described according to the classifications of Vertucci (with the additions of Sert and Bayirli), as well as Ahmed et al. Root number, fusions and canal morphology were recorded. Relationships between morphology, sex and age were assessed using Fisher's exact test (p < 0.05). Maxillary second molars were predominantly three-rooted (96.1%), with root fusion observed in 14%. No relationships between sex, age and canal morphology were found. Additional canals were observed in 67.4% of mesiobuccal roots. The Ahmed et al. classification provided a better overall description of the morphology. In this population, maxillary second molar teeth exhibited a diversity of root and canal morphology. Complex variations may render endodontic management more difficult and increase the possibility of missed anatomy.

A morphometric assessment of developing permanent dentition for age and sex estimation in a select South African sample

Dentition plays a crucial role in the fields of forensic science, forensic odontology and anthropology for age and sex estimation. The aim of this study was to determine the degree of sexual dimorphism and age prediction capabilities of permanent dentition using morphometric analysis. Six hundred digital panoramic radiographs (n = 600), belonging to 300 South African Black and 300 South African Indian, aged between 5.00 and 19.99 years were retrospectively examined using a cross-sectional design. The Pearson Correlation Coefficient tests were conducted to determine if a correlation exist between age, sex and each morphometric parameter. “Stepwise Regression Analysis” and “supervised machine learning classification” with a recursive feature elimination and logistic regression were then utilized to parsimoniously prune the morphometric parameters to determine the best models for age and sex estimation, respectively. Males generally displayed larger tooth dimensions than females, with the South African Black population group having larger tooth dimensions than the South African Indian population group. The morphometric parameters of the dentitions showed little sexual dimorphism, with weak correlations less than 0.1, in this study. However, strong correlations between age and the tooth length of the second and third maxillary and mandibular molars (R2 > 0.89) were recorded for the select South African Black and Indian population groups. In conclusion, the sex estimation formulae generated in this study had low performance accuracies for both population groups. However, the age estimation formulae developed from “Stepwise Regression Analysis” in this study were reliable predictors of age, with the tooth and root lengths displaying the best models for age estimation for the South African Black and Indian sample (R2 > 0.9).

Thirteen cancers associated with HIV infection in a Black South African cancer patient population (1995-2016).

South Africa's HIV epidemic has evolved over time in terms of numbers of people living with HIV, access to antiretroviral treatment (ART) and age. These changes have profoundly influenced local cancer patterns. The Johannesburg Cancer Study has, over a period of 22 years (1995-2016), recruited over 20 000 incident black cancer patients who consented to provide answers to a questionnaire and blood samples (serum, DNA). This has presented a unique opportunity to examine the evolving association of HIV with cancer in Africa. We used logistic regression models to explore case-control associations between specific cancers and HIV, using participants with non-infection related cancers as controls. Using data of 20 835 cancer patients with confirmed HIV status, we found the following cancers to be associated with HIV: Kaposi's sarcoma (ORadj ; 95%CI): (99.1;72.6-135.1), non-Hodgkin lymphoma (11.3;9.3-13.6), cervical cancer (2.7;2.4-3.0), Hodgkin lymphoma (3.1;2.4-4.2), cancer of the eye/conjunctiva (18.7;10.1-34.7), anogenital cancers (anus [2.1;1.4-3.2], penis [5.4;2.7-10.5], vulva [4.8;3.5-6.4], vagina [5.5;3.0-10.2]), oropharyngeal cancer (1.6;1.3-1.9), squamous cell carcinoma of the skin (3.5;2.4-4.9), melanoma (2.0;1.2-3.5) and cancer of the larynx (1.7;1.3-2.4). Kaposi's sarcoma odds ratios increased from the pre-ART (1995-2004) to the early ART (2005-2009) period but declined in the late ART (2010-2016) period. Odds ratios for cancers of the eye/conjunctiva, cervix, penis and vulva continued to increase in recent ART periods. Our study confirms the spectrum of HIV-associated cancers found in other African settings. The odds ratios of conjunctival and HPV-related cancers continue to rise in the ART era as the HIV positive population ages.

Quantifying the temporal changes in geographical-level contributions of risk factors to hypertension (2008–2017): Results from national surveys

South Africa has one of the world's highest proportions of hypertensive individuals, which has become a major public health problem. Understanding the temporal and spatial patterns in hypertension rates is crucial for evaluating the existing prevention and care models, which have not been fully understood in South Africa. The geoadditive models were used to quantify the geographical clustering of hypertension in the Black South African population enrolled in the most recent cross-sectional national surveys (2008–2017). Population-attributable risks were calculated for modifiable risk factors. 80,270 men (41%) and women (59%) aged 15+ were included. Using the 2017 guidelines, 52% of the men and 51% of the women were classified as hypertensive. As expected, these proportions were slightly lower when we used the previous guidelines (48% and 47% for men and women, respectively). There was significant geospatial heterogeneity in hypertension prevalence with substantial province-specific disparities. Western, Northern, and Eastern Capes were the most significant provinces, with >50% of the hypertensive men and women. The population-level impact of obesity remained high in all provinces, where 33%-to-57% and 47%-to-65% of hypertensives were exclusively associated with obese/overweight men and women respectively. Despite some improvements in certain areas, most of the country is behind the targeted levels set in 2011/2013. Identifying the most relevant risk factors and their sub-geographical-level contributions to hypertension may have significant public health implications for developing and implementing cost-effective prevention programs to raise awareness of healthy diet and lifestyle behaviours.

The association of vitamin D binding protein levels and genotypes with type 1 diabetes in the black South African population

BackgroundVitamin D deficiency and the vitamin D pathway have previously been associated with type 1 diabetes (T1D). The majority of vitamin D is transported through the blood bound to the vitamin D binding protein (VDBP). Two polymorphisms in the VDBP gene (rs4588 and rs7041) result in different VDBP variants and have been associated with T1D, however the results are not consistent. The association of VDBP levels and its polymorphisms with T1D have not been investigated in the black South African population. Therefore, this study aimed to determine whether rs4588, rs7041 or serum VDBP levels were associated with T1D in this population.MethodsParticipants with type 1 diabetes and controls were recruited from the greater Johannesburg area, South Africa. Participants were genotyped for rs4588 and rs7041 using PCR-RFLP and serum VDBP levels were determined by ELISA.ResultsThere was no difference in VDBP allelic or genotypic frequencies between participants with T1D and controls (rs4588 C allele frequency 0.92 vs. 0.94; p = 0.390 and rs7041 T allele frequency 0.95 vs. 0.95; p = 0.890). In univariate analysis, the rs4588 CC genotype was associated with increased serum VDBP levels, however, this association was lost with multivariate analysis. The VDBP genotypes were not associated with any other study variables. In logistic regression analysis, higher VBDP levels were associated with T1D (OR: (95% CI): 6.58 (1.45–29.9); p = 0.015), and within a linear regression analysis, T1D disease status was found to be associated with 0.044 mg/ml higher VDBP levels (p = 0.028).ConclusionsThese data suggest that serum VDBP levels are positively associated with the presence of T1D in the African population. Whether VDBP lies in the causal pathway or its elevation is an effect of T1D is uncertain and requires further investigation.

Dyslipidemia in South African patients with hypothyroidism

BackgroundOvert hypothyroidism leads to increased cardiovascular risk, primarily through effects the disorder has on lipids. Most studies investigating lipids in the setting of hypothyroidism, have been performed in predominantly Caucasians in North America and Europe. Different patterns and prevalence of dyslipidemia have been described; one study reporting dyslipidemia in 90% of patients with hypothyroidism. The prevalence of dyslipidemia in overt hypothyroidism among the ethnically diverse predominantly black South African population is unknown. MethodologyA retrospective case-control study evaluating lipid profiles of an ethnically diverse cohort of patients with overt hypothyroidism (TSH > 10 mIU/L) attending two academic hospitals in Johannesburg, South Africa from September 2006–September 2016. Patients with primary or secondary causes for dyslipidemia and those taking lipid-lowering therapy were excluded. ResultsTwo hundred and six patients with hypothyroidism were included and compared to 412 euthyroid controls matched for sex, ethnicity, and age. Most hypothyroid patients were female (n = 180;67.5 %). Median TSH was similar across all ethnic groups (p = 0.09). Median TC, TG and LDL-C were higher in hypothyroid patients (p < 0.01). Normal lipid profiles were found in 29.44 % of all hypothyroid patients. However, a greater proportion, 47 of 124 (37.90 %), black African patients with hypothyroidism had a normal lipid profile. ConclusionDyslipidemia is less common in black African patients with hypothyroidism. This is probably due to this population group being in an earlier stage of epidemiologic transition. Those with hypothyroidism were at greater overall cardiovascular risk based on TC/HDL-C ratio but did not reach high risk atherogenic profiles reported in previous studies.