Black Population Of South Africa Research Articles

Acute kidney injury in the tropics

Acute kidney injury (AKI) is one of the most challenging problems faced by clinicians in the tropics owing to its fast-changing burden. AKI in the tropics is strikingly different from that in the developed world in terms of etiology and presentation. In addition, there is a stark contrast between well-developed and poor areas in the tropics. The true epidemiological picture of AKI in the tropics is not well understood due to the late presentation of patients to tertiary centers. Infections remain the major culprit in most cases of AKI, with high mortality rates in the tropics. Human immunodeficiency virus–related AKI, related to nephrotoxicity due to antiretroviral therapy, is on the rise. Acute tubular necrosis and thrombotic microangiopathy are the most common mechanisms of AKI. A notable problem in the tropics is the scarcity of resources in health centers to support patients who require critical care due to AKI. This article reviews the unique and contrasting nature of AKI in the tropics and describes its management in each situation.

HIV infection and cardiovascular risk in black South Africans

HIV infection and cardiovascular risk in black South Africans

Butterflies and Barbarian: Swiss Missionaries and Systems of Knowledge in South-East Africa

‘Swiss history has a bad press’, notes Patrick Harries in the opening sentence of his book. The study is an excellent example of how this dictum can successfully be challenged. Firmly rooted in both the history of his native South Africa and the country in which his professional and private life is now centred, namely Switzerland, Harries manages to tell the fascinating story of Swiss missionaries in southern Africa in the late nineteenth century. He focuses his attention on French-speaking Calvinists from the Canton of Vaud, who set up the Mission Vaudoise in southern Africa in the 1870s. Their most important representative was Henri-Alexandre Junod (1863–1934), whose book, The Life of a South African Tribe (first edition 1898), is a founding text of South African anthropology which was read far beyond the then still rather small circle of anthropologists—Sigmund Freud used it when writing Totem and Taboo. Yet it was the political uses made of this book in inter-war South Africa that proved to be the most problematic. Harries argues convincingly that, because Junod attempted to ‘salvage’ the Africans he studied from any nocuous European influence, his picture of a completely separate indigenous African society was a precondition for the development of Apartheid: ‘Much of the segregationist legislation passed in the 1920s sought to answer the native question by salvaging the African tribe as the natural home for the black population of South Africa’ (p. 237).

Plasma polyunsaturated fatty acids and liver enzymes in HIV-infected subjects: the Prospective Urban and Rural Epidemiology (PURE) Study

Omega-6 (n-6) polyunsaturated fatty acid (PUFA) intake was previously reported to be adversely related to liver function in HIV-infected subjects, when compared with HIV-uninfected subjects, in a black population in South Africa. It was speculated that the use of heavily oxidized vegetable fats (abused fats) could have been responsible. The objectives were to investigate the relation between plasma total PUFA concentrations (a marker of PUFA intake) and liver enzymes in HIV-infected asymptomatic compared with HIV-uninfected black South Africans and to investigate the reuse of oil and the use of abused oils. This was a case-control study nested in an epidemiologic study in 305 HIV-infected cases and 301 HIV-uninfected matched controls (matched according to location, sex, and age), as part of the PURE (Prospective Urban and Rural Epidemiology) Study, a prospective cohort study that includes a representative sample of 2000 apparently healthy black volunteers, aged between 36 and 60 y, from the North West Province of South Africa. Plasma total omega-6 PUFA concentrations were negatively (P < 0.05) associated with liver enzymes (gamma-glutamyl transpeptidase, alanine aminotransferase, aspartate aminotranferase, and alkaline phosphatase) in both HIV-infected and HIV-uninfected subjects (r values ranged from -0.22 to -0.56). Almost all subjects (99%) reported that they did not buy oil that had been used before. Oil was only used a mean (+/-SD) of 2.23 +/- 0.85 times for deep frying before being discarded. The adverse relations between omega-6 PUFA intake and liver enzymes that were previously shown could not be confirmed in this study. In contrast, plasma omega-6 PUFA concentration was inversely related to liver enzymes in both HIV-infected and HIV-uninfected subjects. Subjects in this study did not use abused fats, which could partly explain these findings.

A rapid method for detection of five known mutations associated with aminoglycoside-induced deafness

BackgroundSouth Africa has one of the highest incidences of multidrug-resistant tuberculosis (MDR-TB) in the world. Concomitantly, aminoglycosides are commonly used in this country as a treatment against MDR-TB. To date, at least five mutations are known to confer susceptibility to aminoglycoside-induced hearing loss. The aim of the present study was to develop a rapid screening method to determine whether these mutations are present in the South African population.MethodsA multiplex method using the SNaPshot technique was used to screen for five mutations in the MT-RNR1 gene: A1555G, C1494T, T1095C, 961delT+C(n) and A827G. A total of 204 South African control samples, comprising 98 Mixed ancestry and 106 Black individuals were screened for the presence of the five mutations.ResultsA robust, cost-effective method was developed that detected the presence of all five sequence variants simultaneously. In this pilot study, the A1555G mutation was identified at a frequency of 0.9% in the Black control samples. The 961delT+C(n) variant was present in 6.6% of the Black controls and 2% of the Mixed ancestry controls. The T1095C, C1494T and A827G variants were not identified in any of the study participants.ConclusionThe frequency of 0.9% for the A1555G mutation in the Black population in South Africa is of concern given the high incidence of MDR-TB in this particular ethnic group. Future larger studies are warranted to determine the true frequencies of the aminoglycoside deafness mutations in the general South African population. The high frequencies of the 961delT+C(n) variant observed in the controls suggest that this change is a common non-pathogenic polymorphism. This genetic method facilitates the identification of individuals at high risk of developing hearing loss prior to the start of aminoglycoside therapy. This is important in a low-resource country like South Africa where, despite their adverse side-effects, aminoglycosides will continue to be used routinely and are accompanied with very limited or no audiological monitoring.

Hepatitis B virus infection: the burden of disease in South Africa

Hepatitis B virus infection, both acute and chronic, occurs commonly in the black population of South Africa, and chronic infection and its sequelae of cirrhosis and hepatocellular carcinoma are major public health threats. Chronic hepatitis B virus infection is rare in the other population groups, with the exception of the very small Chinese community. Prevalences of chronic carriage of hepatitis B virus in South African blacks are 5-16% in rural males, 8-9% in urban males, 4-12% in rural females, and 2.7-4% in urban females. The overall male to female ratio is 2.6:1.0. There are now three to four million South African blacks who are chronically infected with this virus. In rural black populations chronic hepatitis B virus infection is acquired very early in life, predominantly as a result of horizontal transmission of the virus, and by the age of 5 years carrier rates approach those seen in adulthood. A further slight increase occurs at school-going age and a greater increase at the time of becoming sexually active. Urban black carrier rates are significantly lower and the infection is acquired later in life. The decreased urban viral carriage rates occur mainly in the first generation born in an urban environment. Hepatitis B virus accounts for about 60% of clinically evident acute viral hepatitis among blacks and about 10% of chronic hepatitis and cirrhosis. It is the cause of the majority of the many cases of hepatocellular carcinoma that occur in black South Africans. The tumour is more common in males and in rural-born than in urban-born blacks. The close association between chronic hepatitis B virus infection and hepatocellular carcinoma holds true in rural and urban patients and males and females. The association is age-related, being closer in younger patients. Genotypes A and D of hepatitis B virus predominate in South African isolates, with genotype A and its subtype Aa having a particularly high hepatocarcinogenic potential.

Apolipoprotein E genotypes and their relation to lipid levels in a rural South African population 1

Genetic variation at the apolipoprotein E (apoE) locus is an important determinant of plasma lipids. The aim of the present study was to evaluate the association between apolipoprotein E genotype and plasma lipid levels among a rural black population in South Africa. Lipid levels and apoE genotypes were studied in 505 volunteer subjects (363 women, 142 men) resident in the Dikgale demographic surveillance site. Allele frequencies were found to be 0.190 for epsilon2, 0.518 for epsilon3, and 0.293 for epsilon4, indicating a relatively low frequency of the epsilon3 allele and a high frequency of the epsilon4 allele. To determine the effect of apoE polymorphism on lipid levels three groups were formed: namely epsilon2-, epsilon3-, and epsilon4-expressing groups. A significant effect of the apoE genotype on total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C)/Total cholesterol (TC) ratio, and triglycerides was observed. LDL-C was significantly lower and the HDL-C/TC ratio was significantly higher in the epsilon2 group compared with the epsilon3 and epsilon4 groups. Triglyceride levels were significantly higher in the epsilon2 group than in the epsilon3 group. With the unfavourable apoE allele distribution, and the lifestyle changes taking place in rural South African populations, preventive strategies need to be developed to limit a potential epidemic of cardiovascular disease in the black population of South Africa.

Self-induced vomiting -- risk for oesophageal cancer?

Chronic inflammation of the oesophagus is considered a precursor condition for the development of oesophageal cancer. Identification of the causes of chronic oesophageal irritation is therefore relevant in developing preventive measures. Self-induced vomiting is a cultural practice among the black population of South Africa, particularly those living in the Transkei, a region reported to have one of the highest incidences of oesophageal cancer worldwide. We retrospectively examined the association between the practice of self-induced vomiting and the development of cytological features of inflammation in 478 self-selected subjects living in Transkei who underwent early screening for oesophageal cancer. Screening involved brush biopsy, cytological investigation and a questionnaire interview. The prevalence of self-induced vomiting was 80.5% and 79.1% in males and females, respectively, and this was stable across all ages. Furthermore, self-induced vomiting was found to be significantly and independently associated with oesophageal chronic inflammation (odds ratio 1.83, 95% confidence interval: 1.13 - 2.96, p = 0.013). While the association between the cultural practice of self-induced vomiting and oesophageal cancer has previously been hypothesised, this is the first study to report on an association between this practice and oesophageal chronic inflammation. Further studies that take into account the method used, frequency and duration of vomiting, age of commencement and fasting state of subjects practicing self-induced vomiting coupled with accurate indicators of inflammation are needed to elucidate the role of self-induced vomiting in oesophageal pathogenesis.

Prevalence of cardiovascular diseases and associated risk factors in a rural black population of South Africa

To determine the prevalence and associated risk factors of cardiovascular diseases in a rural adult black population from Limpopo Province in South Africa. A cross-sectional study. A sample of 1608 women and 498 men aged 30 years and above participated in the study. Sociodemographic data, anthropometric measures (body mass index, waist/hip ratio), blood pressure and biochemical risk factors were measured. A global cardiovascular disease (CVD) risk profile was developed. There was a high prevalence of tobacco use for men (57%) and women (35.4%), with women (28.1%) predominantly using smokeless tobacco. Alcohol use was very common in men (57.2%). Women weighed a great deal more than men, and 51.7% were either overweight or obese. Diabetes was diagnosed in 8.8 and 8.5% of women and men, respectively. High-density lipoprotein-cholesterol was relatively high, whereas 42.3% of women and 28.5% of men had low-density lipoprotein-cholesterol levels of 3 mmol/l or more. Hypertension (blood pressure > or =140/90 mmHg) was found in 25.5% of women and 21.6% of men. According to the Framingham formulae, 18.9% of women and 32.1% of men had a 20% or higher chance of having a CVD event in the next 10 years. There was a high prevalence of chronic disease risk factors in the rural, poor black community in Limpopo, South Africa. Consequently, the population had a higher than expected risk of developing a CVD event in the following 10 years when compared with similar studies in black Africans.

Environmental Entitlements and the Rural Poor in South Africa

While high expectations regarding the alleviation of poverty accompanied the advent of the new political dispensation in South Africa in 1994, little progress has been made. This article details the dynamics of what is commonly termed the “poverty-environment relationship” in South Africa and focuses the reader’s attention on the continued existence and effects of this phenomenon. The analysis points the way to various new approaches to fighting poverty which still occurs disproportionately among the black population of South Africa, and especially black women, while giving necessary consideration to the environment. The article focuses on factors that structure poor people’s access to environmental resources and their ability to make effective use of them.

Where does the black population of South Africa stand on the nutrition transition?

To review data on selected risk factors related to the emergence of noncommunicable diseases (NCDs) in the black population of South Africa. Data from existing literature on South African blacks were reviewed with an emphasis placed on changes in diet and the emergence of obesity and related NCDs. Review and analysis of secondary data over time relating to diet, physical activity and obesity and relevant to nutrition-related NCDs. Urban, peri-urban and rural areas of South Africa. National prevalence data are also included. Black adults over the age of 15 years were examined. Shifts in dietary intake, to a less prudent pattern, are occurring with apparent increasing momentum, particularly among blacks, who constitute three-quarters of the population. Data have shown that among urban blacks, fat intakes have increased from 16.4% to 26.2% of total energy (a relative increase of 59.7%), while carbohydrate intakes have decreased from 69.3% to 61.7% of total energy (a relative decrease of 10.9%) in the past 50 years. Shifts towards the Western diet are apparent among rural African dwellers as well. The South African Demographic and Health Survey conducted in 1998 revealed that 31.8% of African women (over the age of 15 years) were obese (body mass index (BMI) > or = 30kg m(-2)) and that a further 26.7% were overweight (BMI > or = 25 to <30 kg m(-2)). The obesity prevalence among men of the same age was 6.0%, with 19.4% being overweight. The national prevalence of hypertension in blacks was 24.4%, using the cut-off point of 140/90 mmHg. There are limited data on the population's physical activity patterns. However, the effects of the HIV/AIDS epidemic will become increasingly important. The increasing emergence of NCDs in black South Africans, compounded by the HIV/AIDS pandemic, presents a complex picture for health workers and policy makers. Increasing emphasis needs to be placed on healthy lifestyles.

Haplotype transmission disequilibrium and evidence for linkage of the CHRNA7 gene region to schizophrenia in Southern African Bantu families.

Recent reports have strongly linked markers near the alpha-7 nicotinic cholinergic receptor subunit gene on human chromosome 15q13-q14 to a sensory gating deficit common in schizophrenics, and have shown positive though non-significant results linking this region to the primary phenotype of schizophrenia in a sample of North American families. We therefore tested for linkage between markers in this region of chromosome 15q and schizophrenia in a sample of 15 multiply affected and 5 single case families with schizophrenia drawn from the Bantu-speaking black population of South Africa. An initial replication using markers from the original study gave an affected-only LOD score maximum of 1.08 under a recessive model at Theta=0.00 for D15S1360, a dinucleotide polymorphism found on the same YAC as the alpha-7 receptor gene. Nonparametric affected-only multipoint analysis gave a Z-score of 1. 29, P=0.098, for D15S1360, and Z=1.45, p=0.075 for D15S118. We then increased the resolution of the map with an extended set of 20 markers. Again, two peaks were observed, with NPL scores of 1.81, p=0.037, at D15S1043 and 1.79 at D15S1360 and 1.80 at D15S1010, both p=0.037. Transmission disequilibrium testing of data from D15S1360 gave an allele-wise and genotype-wise chi(2) of 6.59, 2 df, p=0.037. Haplotype transmission disequilibrium testing using a restricted allele and haplotype set from D15S1043 and D15S1360 gave a global chi(2) of 10.647, 4 df, P=0.007, and a maximum chi(2) of 6.567, 1 df, P=0.004 for excess transmission of the 1.2 haplotype into affected offspring. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:196-201, 2000.

Plasma total phenytoin: a possibly misleading test in developing countries.

The use of phenytoin has increased among the rural black population in South Africa, many of whom have albumin concentrations below the accepted reference range of 35-50 g/L, related to a combination of malnutrition and late-presenting renal and hepatic disease. Because albumin concentration has a major effect on the proportion of free phenytoin in the extracellular fluid, we instituted a study of the extent of hypoalbuminemia and of the difference between "total" phenytoin (measured by immunoassay), and "corrected" phenytoin (calculated using the Sheiner-Tozer equation, which is based on a mean albumin of 40 g/L). The differences were significant (higher than 20%) in 37% of patients and led us to propose that in populations in which there is a high proportion of patients who are hypoalbuminemic, it is corrected rather than total phenytoin that should be the value reported.

Ambulatory Blood Pressure and Risk Factors for Coronary Heart Disease in Black and Indian Medical Students

Coronary heart disease (CHD) has reached 'epidemic' proportions in South Africa. CHD is uncommon in the black population of South Africa, yet the prevalence of hypertension in the adult black population is high. This study compared the blood pressure profile in 154 medical students of which 83 were Indians (1), 71 were black (B), 87 were male (50 I, 37 B), and 67 were female (33 I, 34 B) age 21 (SD+/-1.6), using the cuff method and 24 h ambulatory blood pressure monitoring (ABPM). All students underwent ABPM. Biochemical studies for CHD risk factors were done. Electrocardiography (ECG) was performed in all participants and echocardiography in 90. ABPM showed that black students had higher systolic and diastolic blood pressure throughout the day, night and critical time periods compared with the Indian students. Blood pressure load was higher in black (40.8%) than in Indian participants (29.6%; P<0.05) and there was less dipping at night Left ventricular mass was significantly higher in black than in Indian participants (29.6%; P<0.05) and there was less dipping at night. Left ventricular mass was significantly higher in black than in Indian participants. Risk factors leading to CHD were more common in Indian than in black participants. Those with borderline hypertension (blood pressure > or = 130/85 and < or = 140/90 mmHg) had statistically higher serum triglyceride and left ventricular mass than normotensives. Young black people had higher blood pressure readings than young Indian participants in the absence of metabolic abnormalities and had greater cardiac involvement Borderline hypertension is not innocuous. Metabolic risk factors for CHD in Indian people are apparent at an early age. This study emphasizes the need for prevention of risk factors leading to CHD at an early age.

Informed consent for HIV testing in a South African hospital: is it truly informed and truly voluntary?

The purpose of this study was to assess informed consent to human immunodeficiency virus (HIV) testing in a perinatal HIV transmission study in a major referral hospital serving a largely Black population in South Africa. First-time antenatal clinic attenders who were randomly selected from those enrolled in the perinatal HIV study (n = 56) answered questionnaires before and after counseling. Knowledge of HIV transmission and prevention, high at the outset, was little improved after counseling. The acceptance rate for HIV testing was high. Despite assurances that participation was voluntary, 88% of the women said they felt compelled to participate in the study. Informed consent in this setting was truly informed but not truly voluntary.

Failure to exclude a possible schizophrenia susceptibility locus on chromosome 13q14.1-q32 in southern African Bantu-speaking families.

Several recent reports have provided evidence suggesting linkage of markers on chromosome 13q14.1-q32 to schizophrenia in families from England, Wales, Japan and the USA, but not in Chinese families. We tested for linkage between markers in this region and schizophrenia in a sample of 16 families multiply affected with schizophrenia drawn from the Bantu-speaking black population of South Africa. Twelve markers spanning 76 cM of chromosome 13q were examined in these analyses, including 10 markers covering the most positive region in the studies of the English, Welsh and Chinese families, and two additional markers yielding the largest positive LOD scores in the American study. The map of markers used was D13S126-14.6cM-D13S119-12.2cM-D13S144-10.+ ++2cM-D13S160-7.9cM-D13S121-6.3cM -D13S71-1.6cM-D13S122- 4.9cM-D13S128-8.9cM-D13S770-1.4cM-D13S7 79-2.2cM-D13S64-7.4cM-D13S173. Parametric two-point analysis yields strongly negative LOD scores across the region D13S71-D13S64 under all models, and D13S71-D13S173 under a recessive model, when analysing either the whole sample or affected individuals only. ALOD maxima are 0.0 when allowing for heterogeneity for all markers in this subset. Under recessive modelling, the ALOD maximum is 0.717, theta = 0.0, alpha = 0.45, for D13S126 when analysing all samples. Affected-only analysis of this marker yields a maximum LOD score of 0.645, theta = 0.1, and an ALOD maximum of 0.697, theta = 0.0, alpha = 0.55. Non-parametric multipoint analysis of these markers provides no support for excess sharing of alleles identical by descent, although D13S119 and D13S770 show some evidence for excess sharing of alleles identical by state.

A proposed field test for evaluating fitness in elderly hypertensive patients.

There is a very high incidence of hypertension amongst the black population in South Africa. Regular aerobic exercise has been shown to be an effective method of lowering blood pressure. In order to be able to prescribe exercise for patients in a community-based setting, an easily administered exercise test needs to be used. In this study the 6 minute walking test in conjunction with the Borg scale and the Duke Activity Status Index (DASI) were tested on three groups of hypertensive patients from different socio-economic communities. The mean age of the cohort was 64.1 years (SD+-7.9) and males and females were included. The outcome was evaluated by determining the degrees of agreement between the DASI and the age predicted V02max (-0.3295) as well as between the calculated V02max and the age predicted V02max (-0.3045). The tests were easy to administer and the calculations easily done. The agreement between the 6 minute walking test and the DASI test was clinically acceptable (-0.0250). There was no agreement between the values obtained and the age-predicted values. It was concluded that the walking test is a useful field test for exercise performance

Acute Renal Failure in the Black Population of South Africa

Acute Renal Failure in the Black Population of South Africa

The paradox of black pupil enrolment growth rates in South African schools: Reply

In this paper, an outline is presented of a paradoxical feature of past trends in the demand for and supply of schooling to the Black population of South Africa. The paradox is that demand for Black schooling increased despite disincentives to do so under the apartheid policy. As background, a brief historical review of the provision of schooling to Blacks is also presented.

One year surveillance of HIV-1 infection in Johannesburg, South Africa

A sero-epidemiological surveillance study to monitor the prevalence of HIV-1 infection in Johannesburg, South Africa, was commenced in February 1988. The population selected for study were attenders at clinics for sexually transmitted diseases (STD) and at family planning (FP) clinics. In the 12 months of the study 6631 sera were tested. Of the STD attenders, 15 of 1224 black females (1·2%) and 21 of 2482 black males (0·8%) were positive. Of the 449 white males tested 49 were homosexual, amongst whom 10 (20·4%) were positive; in the heterosexual white male group 4 of 400 (1·0%) were positive. Of the FP clinic attenders, 4 of 1459 black females (0·3%) were positive. 68 of the 6631 sera tested were indeterminate for infection. No attenders were positive for HIV-2 infection. These data confirmed the entry of HIV infection into the black population in South Africa.