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Background: There is evidence demonstrating that the contribution of sedentary behavior and effect of physical activity on metabolic phenotypes is mediated by polymorphisms in genes. Methods: The type and frequency of physical activity was assessed by means of structured questionnaires in 1555 South African school learners. Anthropometric measurements, blood pressure, fasting blood glucose and lipids were measured using standard procedures. The effect of different types and frequency of physical activity on obesity-related traits was assessed in relation to MC3R T6K and V811 genotypes in 430 of the learners. Results: Levels of total cholesterol were significantly lower in learners carrying the MC3R T6K and V81I minor alleles, after adjusting for age, race, gender, and each specific physical activity category. An activity-by-genotype interaction was also detected: learners heterozygous for the V81I polymorphism and performed house chores often had reduced total cholesterol. Though no association was observed between frequency of physical activity and BMI, television viewing was significantly associated with an increase in height, weight and marginally with waist circumference. Conclusion: Our findings suggest that physical activity even in the form of house chores has a positive effect on metabolic traits and this effect is further enhanced in the presence of MC3R polymorphisms. [ABSTRACT FROM AUTHOR]

Background: The proposed waist-to-height ratio (WHtR) cut-off of 0.5 is less optimal for cardiometabolic risk screening in children in many settings. The purpose of this study was to determine the optimal WHtR for children from South Africa, and investigate variations by gender, ethnicity and residence in the achieved value. Methods: Metabolic syndrome (MetS) components were measured in 1272 randomly selected learners, aged 10–16 years, comprising of 446 black Africans, 696 mixed-ancestry and 130 Caucasians. The Youden’s index and the closest-top-left (CTL) point approaches were used to derive WHtR cut-offs for diagnosing any two MetS components, excluding the waist circumference. Results: The two approaches yielded similar cut-off in girls, 0.465 (sensitivity 50.0, specificity 69.5), but two different values in boys, 0.455 (42.9, 88.4) and 0.425 (60.3, 67.7) based on the Youden’s index and the CTL point, respectively. Furthermore, WHtR cut-off values derived differed substantially amongst the regions and ethnic groups investigated, whereby the highest cut-off was observed in semi-rural and white children, respectively, Youden’s index0.505 (31.6, 87.1) and CTL point 0.475 (44.4, 75.9). Conclusion: The WHtR cut-off of 0.5 is less accurate for screening cardiovascular risk in South African children. The optimal value in this setting is likely gender and ethnicity-specific and sensitive to urbanization. [ABSTRACT FROM AUTHOR]

Background: Population-based data on the burden of chronic kidney disease (CKD) in sub-Saharan Africa is still very limited. We assessed the prevalence and determinants of CKD, and evaluated the concordance of commonly advocated estimators of glomerular filtration rate (eGFR) in a mixed ancestry population from South Africa. Methods: Participants were a population-based sample of adults selected from the Bellville-South community in the metropolitan city of Cape Town. eGFR was based on the Cockroft-Gault (CG), Modification of Diet in Kidney Disease (MDRD) and CKD Epidemiology Collaboration (CKD-EPI) equations (with and without adjustment for ethnicity). Kidney function staging used the Kidney Disease Outcome Quality Initiative (KDOQI) classification. Logistic regressions and kappa statistic were used to investigate determinants of CKD and assess the agreement between different estimators. Results: The crude prevalence of CKD stage 3-5 was 14.8% for Cockcroft-Gault, 7.6% and 23.9% respectively for the MDRD with and without ethnicity correction, and 7.4% and 17.3% for the CKD-EPI equations with and without ethnicity correction. The highest agreement between GFR estimators was between MDRD and CKD-EPI equations, both with ethnicity correction, Kappa 0.91 (95% CI: 0.86-0.95), correlation coefficient 0.95 (95% CI: 0.94-0.96). In multivariable logistic regression models, sex, age and known hypertension were consistently associated with CKD stage 3-5 across the 5 estimators. Conclusions: The prevalence of CKD stages greater than 3 is the highest reported in Africa. This study provides evidence for support of the CKD-EPI equation for eGFR reporting and CKD classification. [ABSTRACT FROM AUTHOR]

The literature on non-esterified fatty acid (NEFA) concentrations in blood cell membranes from patients with multiple sclerosis (MS) is scarce and reports on concentrations in brain tissue from these patients are inconsistent. NEFAs are needed for several biological functions, for example, as precursors for inflammatory eicosanoid synthesis. The objective of this study was therefore to compare NEFA concentrations in blood cell membranes from patients with that of healthy control subjects, and to correlate possible changes with disease outcome. NEFA C18:2 n-6 (9,12-octadecadienoic acid) was decreased in peripheral blood mononuclear cell membranes from patients, median (quartile range): patients: 0.05 (0.02) and controls: 0.07 (0.14) µg/mg protein, p = 0.007. C18:2 n-6 also showed a weaker relationship with other fatty acids: with C16:0: patients: R = 0.40, p = 0.04; controls: R = 0.82, p = 0.000001. Saturated and MUFA showed positive correlations with the Bowel and bladder Functional System Scores (FSS). In contrast, in red blood cell membranes C18:2 n-6 and C22:0 (docosanoic acid) showed inverse correlations with the Sensory and Brainstem FSS. The decrease in NEFA C18:2 n-6 resulted in metabolic abnormalities between itself and saturated and monounsaturated NEFAs. Altered fatty acid composition in immune cell membranes would influence immune cell functions, and could possibly have contributed to the positive correlations between these fatty acids and disease outcome. Practical applications: Multiple sclerosis (MS) is a disease which presents with inflammation of the central nervous system. The cause of the disease is unknown and treatments such as anti-inflammatory, immunosuppressive medications, and fatty acids supplements are for the alleviation of symptoms only. The results from this study however, showed an altered relationship between polyunsaturated and saturated as well as monounsaturated non-esterified fatty acids in immune cells, which could have contributed to the inflammatory/infectious condition in these patients. The results from this study and further studies could possibly result in formulation of fatty acid supplements at correct doses or ratios for MS patients. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to investigate the levels of non-esterified fatty acids in plasma from patients with multiple sclerosis and further to correlate these findings with the neurological profile as measured by the Kurtzke Expanded Disability Status Scale. Methods: Plasma non-esterified fatty acids and esterified fatty acids from 30 control subjects and 31 patients with multiple sclerosis were measured by gas chromatography. Results: Non-esterified fatty acids C18:2n-6, C20:4n-6, C16:1n-7, C18:1n-7, C18:1n-9, C14:0, C16:0 and C18:0 were significantly increased in plasma from patients with multiple sclerosis, P ≤ 0.01, while esterified fatty acid C18:2n-6 was decreased, P = 0.003. Fatty acid PC C16:1n-7 and non-esterified fatty acids C16:1n-7, C18:1n-7 and C18:1n-9 showed positive and fatty acids C18:1n-9, C20:0, C22:0 and C24:0 showed inverse correlations with the Functional System Scores. Conclusions: We have identified increased monounsaturated non-esterified fatty acids in plasma from patients with multiple sclerosis as indicative of a worse disease outcome. Further, the decrease in fatty acid C18:2n-6, with increases in non-esterified fatty acids C18:2n-6 and C20:4n-6, suggested a role for these eicosanoid precursor fatty acids in the inflammatory condition experienced by these patients. [ABSTRACT FROM AUTHOR]

Background: HbA1c has been the gold standard for glycaemic control follow-up for decades. In 2009, a level of 6.5% (48 mmol/mol) was proposed as diagnostic for diabetes. We test this cut-off in our community. Methods: Participants (946) from a community-based study were screened for diabetes using either a fasting blood glucose or oral glucose tolerance test (OFTT). The HbA1c cut-off of 6.5% was tested for each group. A receiver operator characteristic (ROC) curve for both groups was generated to establish an optimal cut-off. Results: Our study included 224 (23.7%) males and 722 (76.3%) females. Using fasting blood glucose alone, 117 (14%) were diagnosed with diabetes 250% had an HbA1c value of $6.5% (48 mmol/mol). Using an OGTT, 147 (18%) were diagnosed with diabetes 246% had an HbA1c value of $6.5% (48 mmol/mol). ROC curves found a level of 6.1% (43 mmol/mol) to be optimal in both groups (AUC 0.85 and 0.82 respectively). The sensitivities were 80% and 75% and the specificities 77% and 78% respectively. Conclusions: A cut off of 6.5% (48 mmol/mol) is a good diagnostic tool with its high specificity; however the low sensitivity limits its use. We found a level of 6.1% (43 mmol/mol) to be optimal. This emphasizes the need for evidenced based values to be established in various population groups. [ABSTRACT FROM AUTHOR]