The protective role of resveratrol against high glucose-induced oxidative stress and apoptosis in HepG2 cells

High glucose concentrations result in oxidative stress, leading to damage of cellular constituents like DNA, proteins, and lipids, ultimately resulting in apoptosis. Resveratrol, a polyphenol phytoalexin, has been studied for its potential therapeutic effects on diabetes. This study investigated the influence of high glucose (HG) on HepG2 cells and assessed resveratrol's effect on high-glucose-induced oxidative stress and apoptosis. HepG2 cells were cultured for 48 and 72 h with high glucose (40 mM), low resveratrol (25 μM), high resveratrol (50 μM), high glucose + low resveratrol, and high glucose + high resveratrol. After exposure, oxidative and apoptosis-related gene expression was evaluated using quantitative polymerase chain reaction (qPCR), and lactate dehydrogenase (LDH) release was measured using the supernatant. In HepG2 cells cultured with high glucose, all antioxidant enzymes (SOD, superoxide dismutase; GPx1, glutathione peroxidase 1; CAT, catalase; Nrf2, nuclear factor erythroid 2-related factor 2; and NQO1, NAD(P)H quinone oxidoreductase 1) were significantly reduced; however, when HepG2 cells were cultured with resveratrol (25 and 50 μM) and high glucose, the expression levels of all antioxidant enzymes were increased. The anti-apoptotic gene (B-cell lymphoma 2; Bcl2) and the DNA repair gene (Oxoguanine glycosylase-1, OGG1) were significantly decreased following high glucose exposure to HepG2 cells. Surprisingly, the expression levels of Bcl2 and OGG1 were notably elevated after resveratrol treatment. Furthermore, high glucose levels increased the LHD release in HepG2 cells, whereas resveratrol treatment reduced the LDH release. Our results demonstrate that resveratrol provides protection against oxidative stress and apoptosis induced by high glucose in HepG2 cells. Hence, resveratrol shows potential as an effective approach to address the impaired antioxidant response resulting from elevated glucose levels commonly observed in diabetes and metabolic disorders.

Resveratrol attenuates high glucose-induced inflammation and improves glucose metabolism in HepG2 cells

Diabetes mellitus (DM) is characterized by impaired glucose and insulin metabolism, resulting in chronic hyperglycemia. Hyperglycemia-induced inflammation is linked to the onset and progression of diabetes. Resveratrol (RES), a polyphenol phytoalexin, is studied in diabetes therapeutics research. This study evaluates the effect of RES on inflammation and glucose metabolism in HepG2 cells exposed to high glucose. Inflammation and glucose metabolism-related genes were investigated using qPCR. Further, inflammatory genes were analyzed by applying ELISA and Bioplex assays. High glucose significantly increases IKK-α, IKB-α, and NF-kB expression compared to controls. Increased NF-kB expression was followed by increased expression of pro-inflammatory cytokines, such as TNF-α, IL-6, IL-β, and COX2. RES treatment significantly reduced the expression of NF-kB, IKK-α, and IKB-α, as well as pro-inflammatory cytokines. High glucose levels reduced the expression of TGFβ1, while treatment with RES increased the expression of TGFβ1. As glucose levels increased, PEPCK expression was reduced, and GCK expression was increased in HepG2 cells treated with RES. Further, HepG2 cells cultured with high glucose showed significant increases in KLF7 and HIF1A but decreased SIRT1. Moreover, RES significantly increased SIRT1 expression and reduced KLF7 and HIF1A expression levels. Our results indicated that RES could attenuate high glucose-induced inflammation and enhance glucose metabolism in HepG2 cells.

Gestational Exposure to Pesticides Induces Oxidative Stress and Lipid Peroxidation in Offspring that Persist at Adult Age in an Animal Model

Pesticide exposure may induce biochemical alterations including oxidative stress and lipid peroxidation. However, in the context of developmental origin of health and disease, putative trans-generational effect of exposure to pesticides are insufficiently studied. We therefore aimed to evaluate the biochemical effect of gestational exposure to four pesticides on female Wistar rats and their offspring at adult age. We studied 30 female nulliparous Wistar rats divided into 5 equal groups. Group 1 served as the control group and received distilled water while group 2, 3, 4 and 5 received orally pesticide 1 (imidacloprid), pesticide 2 (chlorpyrifos), pesticide 3 (imidacloprid + lambda cyhalothrin) and pesticide 4 (oxamyl) respectively once daily throughout gestation at a dose equivalent to 1/10 lethal dose 50. The mothers were followed up until one month post gestation. The offspring were followed up from birth until adult age (12 weeks). In all animals at each time point we evaluated malondialdehyde (MDA), oxidative stress and liver function enzymes. There was similar variation of total body weight in all the groups during and after gestation. However, Female Wistar rats of the exposed groups had significant alterations in liver SOD (-30.8% to +64.1%), catalase (-38.8% to -85.7%) and GSH (-29.2% to -86.5%) and; kidney catalase (> 100%), GSH (> 100%). Moreover, MDA, alanine transaminase (ALT) and aspartate transaminase (AST) levels were significantly higher in pesticide exposed rats compared to the control group. Similar alterations in antioxidant enzymes, MDA and liver function enzymes were observed in offspring of treated rats evidenced at weaning and persisting until adult age. Exposure to pesticides causes oxidative stress and lipid peroxidation in exposed female Wistar rats and their offspring. The persistence in offspring at adult age suggests transgenerational adverse effects.

The role of pollutants in type 2 diabetes mellitus (T2DM) and their prospective impact on phytomedicinal treatment strategies

Type 2 diabetes mellitus (T2DM) is the most common form of diabetes and it is characterized by high blood sugar and abnormal sera lipid levels. Although the specific reasons for the development of these abnormalities are still not well understood, traditionally, genetic and lifestyle behavior have been reported as the leading causes of this disease. In the last three decades, the number of diabetic patients has drastically increased worldwide, with current statistics suggesting the number is to double in the next two decades. To combat this incurable ailment, orthodox medicines, to which economically disadvantaged patients have minimal access to, have been used. Thus, a considerable amalgamation of medicinal plants has recently been proven to possess therapeutic capabilities to manage T2DM, and this has prompted studies primarily focusing on the healing aspect of these plants, and ultimately, their commercialization. Hence, this review aims to highlight the potential threat of pollutants, i.e., polyfluoroalkyl compounds (PFCs), endocrine disrupting chemicals (EDCs) and heavy metals, to medicinal plants, and their prospective impact on the phytomedicinal therapy strategies for T2DM. It is further suggested that auxiliary research be undertaken to better comprehend the factors that influence the uptake of these compounds by these plants. This should include a comprehensive risk assessment of phytomedicinal products destined for the treatment of T2DM. Regulations that control the use of PFC-precursors in certain developing countries are also long overdue.

Recent developments in polyfluoroalkyl compounds research: a focus on human/environmental health impact, suggested substitutes and removal strategies

Between the late 1940s and early 1950s, humans manufactured polyfluoroalkyl compounds (PFCs) using electrochemical fluorination and telomerisation technologies, whereby hydrogen atoms are substituted by fluorine atoms, thus conferring unnatural and unique physicochemical properties to these compounds. Presently, there are wide ranges of PFCs, and owing to their bioaccumulative properties, they have been detected in various environmental matrices and in human sera. It has thus been suggested that they are hazardous. Hence, this review aims at highlighting the recent development in PFC research, with a particular focus on perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS), the most studied and predominantly found PFCs in various environmental matrices, although recent reports have included perfluorobutane sulfonate (PFBS), which was previously regarded as innocuously harmless, when compared to its counterparts, PFOA and PFOS. As such, proper investigations are thus required for a better understanding of short-chain PFC substitutes, which have been suggested as suitable replacements to long-chained PFCs, although these substitutes have also been suggested to pose various health risks comparable to those associated with long-chain PFCs. Similarly, several novel technologies, such as PFC reduction using zero-valent iron, including removal at point of use, adsorption and coagulation, have been proposed. However, regardless of how efficient removers some of these techniques have proven to be, short-chain PFCs remain a challenge to overcome for scientists, in this regard.

The fat mass and obesity-associated FTO rs9939609 polymorphism is associated with elevated homocysteine levels in patients with multiple sclerosis screened for vascular risk factors

The previously reported link between homocysteine and obesity, both identified as established risk factors for multiple sclerosis (MS), has not previously been studied in relation to the fat mass and obesity-associated (FTO) gene.

AIM

To investigate the mechanism underlying homocysteine accumulation in MS patients. A total of 114 patients and 195 population-matched controls were analysed for the FTO rs9939609 polymorphism. Homocysteine levels were measured in a subgroup of 60 patients and 87 controls screened for multiple vascular risk factors. After adjustment for potential confounders, the risk-associated FTO rs9939609 A-allele was associated with raised homocysteine levels (p = 0.003) in patients diagnosed with MS, but not in controls. Homocysteine levels correlated positively with body mass index (BMI) (p = 0.045) and total cholesterol levels (p = 0.048). Both homocysteine (p = 0.011) and BMI (p = 0.017) were significantly reduced with higher intake of folate in the diet. Higher BMI also correlated with increased intake of saturated/trans fat (p < 0.01) and low physical activity (p < 0.006). Daily intake of at least five fruits and vegetables had a favourable lowering effect on the Expanded Disability Status Scale (EDSS) (p = 0.035), while smoking increased MS disability (p < 0.001). This study has shown for the first time that having a diagnosis of MS moderates the effect of the FTO rs9939609 polymorphism on homocysteine levels. This is consistent with the role of FTO in demethylation and epigenetic changes. Identification of FTO rs9939609 reinforces the importance of adequate fruit, vegetable and folate and restriction of saturated/trans fat intake in the diet.

Low prevalence of human herpesvirus-6 and varicella zoster virus in blood of multiple sclerosis patients, irrespective of inflammatory status or disease progression

Herpesviruses, including human herpesvirus-6 and varicella zoster virus, have been implicated in the disease aetiology of multiple sclerosis. These viruses are capable of reactivation, reminiscent of the relapsing-remitting nature of multiple sclerosis. However, viral DNA has also been reported present in healthy controls, often at similar prevalence rates. This study aimed to determine whether prevalence could be associated with different stages of activity of the disease as well as the inflammatory status of the patients. Polymerase chain reaction assays were used to screen for human herpesvirus-6 and varicella zoster virus DNA in blood from 31 Caucasian patients with multiple sclerosis and 30 healthy age, sex and race matched control subjects. The patients were screened for inflammation using C-reactive protein as a marker and were also categorized according to their remitting/relapsing status. Results were positive for human herpesvirus-6 in blood from only one patient (3.2%) and human herpesvirus-6 DNA was not present in any control subjects. Varicella zoster virus was not detected in either the patients or control subjects. Similar to some other studies we saw an absence or very low viral positivity in blood from both patients and controls. These findings were irrespective of relapse episodes, increased inflammatory status or duration of the disease. Results therefore do not support a causative role for either human herpesvirus-6 or varicella zoster virus in the disease aetiology of multiple sclerosis, but rather that prevalence in patients may be linked to that of the general population.

Distribution and association of hs-CRP with cardiovascular risk variables of metabolic syndrome in adolescent learners

OBJECTIVE

Metabolic syndrome (MetS) and its associated cardiovascular risk are on the increase in children. High-sensitivity C-reactive protein (hs-CRP) has emerged as a useful marker for inflammation associated with atherosclerosis and cardiovascular disease. Our aim was to determine the distribution of hs-CRP in an effort to identify the MetS variable that is critical in modulating plasma CRP levels in a population of South African adolescents.

DESIGN

A cross-sectional analytical study design was used for this investigation, where the dependent and independent variables were measured simultaneously.

METHODS

Anthropometric variables, blood pressure, fasting blood glucose and lipids were performed on 324 consenting learners aged 15-18 years from three different ethnic groups (Black, White and Coloured). The National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) for ages 15-18 year olds was used to define MetS.

RESULTS

The prevalence of MetS and obesity was 3.7% and 7.1%, respectively. The hs-CRP levels were significantly higher in subjects with a waist-circumference greater than the 90th percentile (p < 0.01) and in obese learners with MetS, but was lower in adolescents with normal weight and MetS. Median hs-CRP levels increased with an increasing number of metabolic abnormalities and exceeded 3 mg/L in 19% of adolescents. Gender and ethnic differences were observed.

CONCLUSION

Our findings suggest that obesity and waist circumference appear to be major mediators of hs-CRP levels in South African adolescents.

Peripheral blood mononuclear cell membrane fluidity and disease outcome in patients with multiple sclerosis

Immune cell membrane lipids are important determinants of membrane fluidity, eicosanoid production and phagocytosis and fatty acid metabolic abnormalities have been reported in immune cells from patients with multiple sclerosis. The aim of this study was to investigate the relationship between peripheral blood mononuclear cell membrane fluidity, permeability status, and disease outcome as measured by the Kurtzke expanded disability status scale. Phospholipids, fatty acids and cholesterol composition in peripheral blood mononuclear cells from 26 patients diagnosed with multiple sclerosis and 25 healthy control subjects were determined by colorimetric assay, gas chromatography and enzymatic assays, respectively. Membrane fluidity was calculated according to previously established formulae and correlated with C-reactive protein and the Kurtzke expanded disability status scale. There were no significant differences in membrane lipids in peripheral blood mononuclear cells from patients and controls. However, correlation studies showed lipid metabolic abnormalities, which were reflected in significant correlations between membrane fluidity as measured by both its fatty acid and phospholipid compositions, and the functional system scores. C-reactive protein showed positive correlations with phosphatidylcholine, phosphatidylserine, phosphatidylinositol and total phospholipids in membranes from control subjects. Metabolic abnormalities, as well as correlations between membrane fluidity and the functional system scores, suggested the involvement of these immune cell membranes in the disease progression. Furthermore, the changed relationship between membrane phospholipids and C-reactive protein, which has been shown to correlate with infectious episodes and clinical relapse, could be an indication of immune cell dysfunction in patients with multiple sclerosis.

Monounsaturated fatty acids in blood cell membranes from patients with multiple sclerosis

The aim of this study was to investigate whether blood cell membrane monounsaturated fatty acids were associated with inflammation and disease outcome in patients with multiple sclerosis. The fatty acid composition in peripheral blood mononuclear cell and red blood cell membranes from 26 patients and 25 controls were determined by gas chromatography. Results showed positive associations between C-reactive protein and C16:1n-7, C18:1n-7, and C24:1n-9 in membranes from controls only. In general, C18:1n-9 and C20:1n-9 showed inverse correlations, while C16:1n-7 and C18:1n-7 showed positive correlations with disease outcome. Multiple sclerosis has a known inflammatory component. There is scarcity of literature on the role of monounsaturated fatty acids in inflammation, but results from this study suggested an association in healthy subjects between monounsaturated fatty acids and C-reactive protein, even at physiologically low levels. This association was not found in the plasma from patients. Furthermore, the n-9 and n-7 fatty acids played different roles in disease outcome, and therefore warrant inclusion, together with polyunsaturated fatty acids when investigating the inflammatory aspects of the disease.

Association of the ENPP1 rs997509 polymorphism with obesity in South African mixed ancestry learners

BACKGROUND

The Ectonucleotide Pyrophosphatase Phosphodiesterasel (ENPP1) polymorphisms have been associated with metabolic traits. There is no data on the effect of ENPP1 in South African children or adults.

OBJECTIVE

To investigate the role of K121Q (rs1044498), rs997509 and rs9402349 in obesity and other components of the metabolic syndrome.

DESIGN

A case-control study.

SUBJECTS

Sixty four obese and 64 lean mixed ancestry learners.

SETTING

Western Cape, South Africa.

MAIN OUTCOME MEASURE

The ENPP1 rs997509T allele is independently associated with obesity in children of mixed ancestry from South Africa.

RESULTS

The T allele frequency of the rs997509 differed significantly between obese and controls, p=0.0100 and increased the risk of being obese, p = 0.0238. Furthermore, the estimated effect of the T allele was an increase of 8.6 cm in waist circumference, 10.2 kg in weight and a corresponding 4.9 kg/m2 in BMI. Individuals carrying both the 121Q and the T allele of rs997509 were more associated with obesity (odds ratio = 3.85, 95% CI: 1.13 to 13.09) whilst those carrying the C allele of rs997509 in the presence of 121Q were likely to be lean with odds ratio of obesity 0.41 (95% CI: 0.19 to 0.87).

CONCLUSION

Our findings suggest that ENPP1 polymorphisms may contribute to different metabolic characteristics, all of which are associated with insulin resistance in mixed ancestry children of South Africa. However, a larger study is required to confirm findings of this study.

Membrane saturated fatty acids and disease progression in multiple sclerosis patients

The risk of developing multiple sclerosis is associated with increased dietary intake of saturated fatty acids. We determined the fatty acid composition within the different phospholipid fractions of red blood and peripheral blood mononuclear cell membranes of 31 patients diagnosed with multiple sclerosis and 30 healthy control subjects using gas chromatography. Individual saturated fatty acids were correlated with the severity of neurological outcome as measured by the Kurtzke Expanded Disability Status Scale. Significant increases were found in multiple sclerosis peripheral blood mononuclear cell membrane sphingomyelin C14:0 and phosphatidylinositol C22:0. In the peripheral blood mononuclear cell membranes, C22:0 and C24:0 showed positive correlations, while C14:0, C16:0 and C20:0 showed inverse correlations with the Functional System Scores. In conclusion, this study is in accordance with previous studies that have shown an increase in shorter long-chain SATS in MS patients. In addition, this study also showed that higher C14:0 and C16:0 reflected better disease outcome as demonstrated by the inverse correlation with the EDSS and FSS. We have also characterized the specific SATS, that is, long-chain SATS that may increase the risk of developing MS.

Erythrocyte membrane fatty acids in patients with multiple sclerosis

Background

Reports on fatty acids levels in multiple sclerosis remain inconclusive.

Objective

To determine the erythrocyte membrane fatty acid levels in multiple sclerosis patients and correlate with Kurtzke Expanded Disability Status Scale.

Methods

Fatty acid composition of 31 multiple sclerosis and 30 control individuals were measured by gas chromatography.

Results

The membrane phosphatidylcholine C20:4 n – 6 concentration was lower in the multiple sclerosis patients when compared to that of the control group, P = 0.04 and it correlated inversely with the EDSS and FSS.

Conclusion

Decrease in C20:4 n – 6 in the erythrocyte membrane could be an indication of depleted plasma stores, and a reflection of disease severity.

Expression of p53 and its homolog, p73, in HPV DNA positive oesophageal squamous cell carcinomas

Several studies have detected human papilloma virus (HPV) DNA in squamous cell carcinoma of the oesophagus (OSCC). In this study, we analysed OSCC specimens from 114 patients for the presence of HPV DNA, and p53 and p73 expression. HPV DNA was detected in 44.7% of cases, with the low risk HPV11 occurring most frequently. p53 and p73 expression was detected in 70% and 61.4% of cases, respectively. There was no correlation between expression of p53, p73 or HPV infection and tumour grade, or between p53 expression and the presence of HPV DNA. There was, however, significant correlation between p73 expression and the presence of HPV DNA (p<0.01) and p53 and p73 co-expression (p<0.001), as well as co-expression of p53 and p73 with HPV status (p<0.05). These data support previous studies suggesting a role for HPV infection in OSCC and also indicate that HPV infection and p53 and p73 overexpression are not mutually exclusive. In addition, the data implicate a role for p73 in OSCC and suggest a complex interaction between p53, p73 and HPV in the aetiology of the disease.

Traditional home-brewed beer consumption and iron status in patients with esophageal cancer and healthy control subjects from Transkei, South Africa

Consumption of home-brewed beer is associated with dietary iron excess and a high incidence of esophageal cancer in Transkei, South Africa. We examined the relationship between home-brewed beer consumption and body iron status in 234 patients with esophageal squamous cell carcinoma and 595 control subjects residing in Transkei. Subjects were screened for iron overload using transferrin saturation >45%, and/or serum ferritin >200 microg/l for women and >300 microg/l for men. A questionnaire was administered to all subjects, and iron content of randomly selected home-brewed beer samples was determined. The iron content of home-brewed beer was 258-fold higher than the commercial Castle Lager beer produced by South African Breweries. The prevalence of home-brewed beer consumption was 30.1% in esophageal cancer patients and 15.5% in control subjects and was found not to be a risk factor for esophageal cancer after adjustment for age, sex, and tobacco consumption (male subjects, odds ratio= 1.6 (95% confidence interval [CI]: 0.7-4.5); female subjects, odds ratio=1.7 (95% CI: 0.7-4.5). Iron overload as determined by transferrin saturation and elevated serum ferritin was observed in 4.3% of patients with esophageal cancer and 0.7% of control subjects and was not associated with the consumption of home-brewed beer. Consumption of home-brewed beer is not a risk factor for esophageal cancer and is not linked with iron overload in either cancer patients or control subjects; however, iron overload is likely to result from a combination of dietary intake and a genetic component.

Iron and the folate-vitamin B12-methylation pathway in multiple sclerosis

Some subjects with multiple sclerosis (MS) present with low blood iron parameters. Anecdotal reports and a single patient study suggest that iron supplementation may be beneficial in these subjects. Myelin is regenerated continually, but prerequisites for this process are iron and a functional folate-vitamin B12-methylation pathway. The aim of this study was to determine iron status, folate and homocysteine in MS subjects, and to evaluate the effect on MS symptoms if deficiencies were addressed.

RESULTS

In relapsing-remitting MS subjects, serum iron concentration correlated significantly with age at diagnosis (r=0.49; p=0.008). In Caucasian female MS subjects, serum iron and ferritin concentrations were significantly lower than in matched controls. In a 6-month pilot study, 12 subjects taking a regimen of nutritional supplements designed to promote myelin regeneration, improved significantly neurologically as measured by the Kurzke EDSS (Total Score means 3.50 to 2.45, 29.9%; p=0.021). These were significantly improved (p=0.002) compared to 6 control group patients taking multivitamins (Kurzke Score increased by 13.9% from 4.83 to 5.50). Both groups had significantly reduced homocysteine concentrations at 6 months, suggesting that methylation is necessary but not sufficient for myelin regeneration.

Self-induced vomiting -- risk for oesophageal cancer?

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Human papillomavirus associated with oesophageal cancer

AIM

To study the prevalence and the different types of human papillomavirus (HPV) in patients with oesophageal cancer from a high risk area of South Africa (Transkei).

METHODS

DNA samples from 50 paraffin wax embedded tissue sections were analysed by nested polymerase chain reaction (PCR) using the degenerate HPV L1 consensus primer pairs MY09/MY11 and GP5+/GP6+. Positive PCR samples were subjected to DNA sequence analysis.

RESULTS

HPV DNA was detected in 23 of the 50 samples. Sequence analysis revealed that most patients (11) harboured DNA to HPV type 11, whereas other types included DNA HPV type 39 (seven patients), type 16 (two patients), and type 52 (one patient). HPV type 39 has not previously been shown to be associated with oesophageal cancer. In contrast to earlier studies that have found HPV type 16 to be more frequently associated with oesophageal cancer, HPV type 11 was the predominant subtype in this study.

CONCLUSIONS

The high frequency of occurrence of HPV in oesophageal tumours (23 of 50 patients; 46%) implicates HPV as one of the possible aetiological factors in this disease. The finding that the low risk HPV subtypes predominate indicates that transformation may be effected via the E6 and E7 proteins.

Importance of family history in type 2 black South African diabetic patients

OBJECTIVE

To assess the family history of diabetes in type 2 black South African diabetics with emphasis on the parental phenotype.

DESIGN

Prospective case-control study in which family histories were obtained from patients.

SETTING

Diabetic clinic of a provincial teaching hospital in the Transkei region of South Africa.

SUBJECTS

A total of 1111 type 2 diabetics attending the diabetic clinic and 687 controls.

MAIN OUTCOME MEASURES

History of diabetes in parents, siblings, maternal and paternal grandparents, aunts, and uncles.

RESULTS

Altogether 27.3% of diabetic subjects had a family history of diabetes compared with 8.4% in the control group (p<0.01). Among the group with positive family history 82.6% reported only one diabetic family member, while 17.4% reported at least two relatives; 6.6% had a diabetic relative from both maternal and paternal sides, and 87.8% had first degree relative with diabetes. Among them there was a significant maternal aggregation with 64.7% of patients having a diabetic mother compared with 27% who had a diabetic father (p<0.01). No maternal effect was observed among the second and third degree relatives. Patients with positive family history had an earlier onset of diabetes than those without family history (p<0.01).

CONCLUSION

These data suggest that type 2 diabetes is heritable in black South African diabetics. It is also likely that maternal influences may play an important part.

Prevalence of diabetes mellitus and impaired glucose tolerance in factory workers from Transkei, South Africa

OBJECTIVE

To determine the prevalence of diabetes mellitus and impaired glucose tolerance (IGT) in a group of peri-urban black South Africans.

DESIGN

Cross-sectional study in which an oral glucose tolerance test (OGTT) was performed on each subject.

SETTING

Two of the largest factories in the surroundings of Umtata, the capital of the former homeland of Transkei, South Africa.

SUBJECTS

A total of 374 Xhosa-speaking factory workers.

MAIN OUTCOME MEASURES

Frequency of diabetes mellitus and IGT according to age group and gender using the current World Health Organisation (WHO) criteria for the diagnosis of abnormal glucose tolerance and its relationship to obesity.

RESULTS

The crude prevalences for diabetes mellitus and IGT were 2.45% and 2.7% respectively. The age-adjusted prevalences using a standard world population were 4.5% (confidence interval (CI) 1.54-7.42) and 5.1% (CI 2.45-5.51) for diabetes and IGT respectively. The prevalence of diabetes was similar in male and female workers (P = 0.31), with the highest incidence observed in the age group from 40 to 59 years. No subject below the age of 40 years was found to be diabetic, and the prevalence of the disease was found to increase with age. Obesity was present in 22.2% of all subjects. Prevalence of obesity was similar in subjects with diabetes and in those with impaired and normal glucose tolerance (P = 0.71). However, overweight, identified in 26.8% of subjects, was more frequently observed in the IGT group than in the other two groups (P = 0.01). IGT was observed in 3.4% of male and 1.5% of female workers respectively (P = 0.13), with peak prevalences occurring between the ages of 30 and 49 years.

CONCLUSION

In conclusion, this study found a prevalence of diabetes and IGT comparable to prevalence results reported in other black South African communities. The implications with regard to this community merit further study.

Assessment of glycaemic control in stable type 2 black South African diabetics attending a peri-urban clinic

Glycaemic control was assessed in type 2 black diabetics attending the diabetic clinic at a peri-urban hospital. Baseline glycosylated haemoglobin levels were measured and a subsequent estimation was carried out in those patients who attended a follow-up consultation to see whether current recommended targets for glycosylated haemoglobin levels were being attained. Out of 708 patients, mean age 56.3 years, 14.7% were insulin treated and 85.3% were non-insulin-treated. Target values of HbA1c < 7% were achieved in only 20.1% (142) of patients. Although mean glycosylated haemoglobin levels were significantly higher in females (p = 0.03), the proportion of poorly controlled diabetics was similar in the two sexes. Patients whose HbA1c levels fell within the target values had diabetes of significantly shorter duration than those exhibiting poor control (5.0 + 0.2 vs 7.03 + 0.5 years). Obesity was present in 562 patients (79.4%). Target values were only achieved in 16.4% of non-obese and 21% of obese diabetics, with mean glycosylated haemoglobin levels being significantly higher (p < 0.05) in the former group (10.3 + 0.4% vs 9.5 + 0.2%). Similar results were observed with respect to type of treatment, with only 14.4% of insulin-treated and 21% of non-insulin-treated diabetics achieving target values. The follow-up HbA1c estimation did not show any difference in the glycaemic control status of patients, with only 19.9% of them achieving the target values. Dietary advice (though minimal) seemed to have no impact on the metabolic control of our patients. These results suggest that glycaemic control was poor irrespective of sex, duration, BMI, educational status, dietary advice and type of treatment with recommended target values not being achieved in the majority of patients. Behavioural changes through health educational programmes need to be instituted with both patient and medical personnel being motivated to take this process forward.