Browsing by Author "Matsha, T. E."

Now showing 1 - 5 of 5
  • No Thumbnail Available
    Item
    Gas chromatography results interpretation: Absolute amounts versus relative percentages
    (InTech, 2012) Hon, G. M.; Abel, S.; Smuts, C. M.; van Jaarsveld, P.; Hassan, S.; Janse van Rensburg, S.; Erasmus, R. T.; Matsha, T. E.
  • Thumbnail Image
    Item
    Increase in blood pressure over a 7-year period in a mixed-ancestry South African population
    (Health & Medical Publishing Group, 2019) Davids, S. F. G.; Matsha, T. E.; Peer, N.; Erasmus, R. T.; Kengne, A. P.
    Background. An increase in the prevalence of high blood pressure (BP) has been reported globally and in the South African (SA) population. Objectives. To investigate temporal changes in absolute BP levels and hypertension prevalence in the mixed-ancestry South Africans. Methods. Participants were from two independent cross-sectional surveys conducted during 2008/09 (N=928) and 2014/16 (N=1 969) in Bellville South, Cape Town, SA. Participants’ eligibility was based on several criteria, including age >20 years and neither bedridden nor pregnant. Data were obtained by administered questionnaires, clinical measurements (BP and anthropometry) and biochemical assessments (oral glucose tolerance tests and cotinine levels). Known hypertension was based on a self-reported history of doctor-diagnosed hypertension and ongoing treatment. Comparison across years was based on the crude prevalence of hypertension as well as direct age-standardised prevalence, based on the SA 2011 mixed-ancestry population distribution, in 10-year age increments. Results. In all, 708 participants (76.3%) in 2008/09 and 1 488 (75.6%) in 2014/16 were female. Between 2008/09 and 2014/16, mean systolic BP increased from 124 to 136 mmHg (absolute mean difference 15 mmHg) and mean diastolic BP from 75 to 85 mmHg (absolute mean difference 9 mmHg) in the overall sample. The prevalence of screen-detected hypertension increased from 11.6% to 24.8%, with a similar increase in males and females, while the prevalence of known cases remained stable. These changes remained significant after adjustment for age and gender. Conclusions. A rightward shift in absolute BP translated into a significant increase in the prevalence of hypertension over time in this population. The predominant increases in screen-detected hypertension suggest that the deteriorating profile was not matched by efforts to detect and manage individuals with higher-than-optimal BP levels.
  • Thumbnail Image
    Item
    Indices of paraoxonase and oxidative status do not enhance the prediction of subclinical cardiovascular disease in mixed-ancestry South Africans
    (Hindawi Publishing Corporation, 2014-03-27) Macharia, M.; Kengne, A. P.; Blackhurst, D. M.; Erasmus, R. T.; Hoffmann, M.; Matsha, T. E.
    We evaluated the association of indices of paraoxonase (PON1) and oxidative status with subclinical cardiovascular disease (CVD) in mixed-ancestry South Africans. Participantswere 491 adults (126 men)whowere stratified by diabetes status and bodymass index (BMI). Carotid intima-media thickness (CIMT) was used as a measure of subclinical CVD. Indices of PON1 and oxidative status were determined by measuring levels and activities (paraoxonase and arylesterase) of PON1, antioxidant activity (ferric reducing antioxidant power and trolox equivalent antioxidant capacity), and lipid peroxidation markers (malondialdehyde and oxidized LDL). Diabetic subjects (28.9%) displayed a significant decrease in PON1 status and antioxidant activity as well as increase in oxidized LDL and malondialdehyde. A similar profile was apparent across increasing BMI categories. CIMT was higher in diabetic than nondiabetic subjects (P < 0.0001) but showed no variation across BMI categories. Overall, CIMT correlated negatively with indices of antioxidant activity and positivelywithmeasures of lipid oxidation. Sex, age, BMI, and diabetes altogether explained 29.2% of CIMT,with no further improvement fromadding PON1 and/or antioxidant status indices.Though indices of PON1 and oxidative status correlate with CIMT, their measurements may not be useful for identifying subjects at high CVD risk in this population.
  • Thumbnail Image
    Item
    Negative association of MC3R variants with weight and blood pressure in Cape Town pupils aged 11 - 16 years
    (Health and Medical Publishing Group (HMPG), 2011-06) Yako, Y. Y.; Fanampe, B. L.; Hassan, S. M.; Erasmus, R. T.; Van der Merwe, L.; Matsha, T. E.
    Background. Human and animal studies support the role of MC4R and MC3R in human obesity, but limited data are available on the genetic contribution to obesity in South African populations. Objective. To screen obese-overweight South African pupils for MC3R and MC4R polymorphisms that may play a role in the development of obesity. Design. A cross-sectional study screened 227 obese-overweight (115 black and 112 coloured) and 204 normal weight (94 black, 110 coloured) school pupils for the presence of MC4R and MC3R polymorphisms using a single strand conformation polymorphism, subsequent sequencing, and allele specific restriction enzyme analysis. Results. Two polymorphisms were detected in the MC3R (T6K and V81I) but none in MC4R. After adjusting for age, gender and case-control status, the frequency distributions of T6K and V81I genotype and allele varied significantly between the ethnic groups. The frequency of the V81I A allele was significantly lower in coloured overweight-obesity than normal pupils. In coloured pupils, both polymorphisms were associated with obesity indices and total cholesterol. The T6K A allele was also associated with lower blood pressure. Likewise, different T6K-V81I haplotypes demonstrated negative associations with obesity indices and blood pressure. Conclusion. We demonstrated that the MC3R polymorphisms have a protective effect on metabolic traits; however, further analysis is required to confirm whether this translates to a lower incidence of metabolic syndrome in coloured populations.
  • Thumbnail Image
    Item
    Paraoxonase 1 genetic polymorphisms in a mixed ancestry African population
    (Hindawi Publishing Corporation, 2014-11-16) Macharia, M.; Kengne, A. P.; Blackhurst, D. M.; Erasmus, R. T.; Matsha, T. E.
    Paraoxonase 1 (PON1) activity is markedly influenced by coding polymorphisms, Q/R at position 192 and M/L at position 55 of the PON1 gene. We investigated the frequencies of these polymorphisms and their effects on PON1 and antioxidant activities in 844 South African mixed ancestry individuals. Genotyping was done using allele-specific TaqMan technology, PON1 activities were measured using paraoxon and phenylacetate, oxidative status was determined by measuring the antioxidant activities of ferric reducing antioxidant power and trolox equivalent antioxidant capacity, and lipid peroxidation markers included malondialdehyde and oxidized LDL. The frequencies of Q192R and L55Mwere 47.6% and 28.8%, respectively, and the most common corresponding alleles were 192R (60.4%) and 55M (82.6%).The Q192 was significantly associated with 5.8 units’ increase in PON1 concentration and 15.4 units’ decrease in PONase activity after adjustment for age, sex, BMI, and diabetes, with suggestion of differential effects by diabetes status.The PON1 L55 variant was associated with none of the measured indices. In conclusion, we have shown that the Q192R polymorphism is a determinant of both PON1 concentration and activity and this association appeared to be enhanced in subjects with diabetes.