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.

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.