The relationship between indices of iron status and selected anthropometric cardiovascular disease risk markers in an African population: the THUSA study.

There is evidence that certain indices of iron status are associated with anthropometric measures, which are used independently as markers of cardiovascular disease (CVD) risk. This study examined whether this association exists in an African population. The study was a cross-sectional comparative study that examined a total of 1 854 African participants. Ferritin was positively associated with body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), percentage body fat and subscapular skinfold thickness. Serum ferritin concentration was higher in the high-WHR category than the normal-WHR category for both genders. Additionally, WC and WHR increased with increasing ferritin concentrations in both genders. Serum iron was lower in the obese than the normal-weight and pre-obese women only. In this population-based study, increased serum ferritin concentrations associated positively with increased WHR and WC, indicating that individuals or populations at risk of iron overload as defined by high serum ferritin concentrations may be at a greater risk of developing CVD.

Association between insulin-like growth factor-1, insulin-like growth factor-binding protein-1 and leptin levels with nutritional status in 1-3-year-old children, residing in the central region of Limpopo Province, South Africa.

The present study evaluated levels of growth factors and their associations with nutritional status with emphasis on stunting in children at 1 and 3 years of age. A follow-up study on a birth cohort (n 219) of children from villages in the central region of the Limpopo Province was undertaken. Of the original cohort, 156 and 162 could be traced and assessed at ages 1 and 3 years, respectively. Data collected included socio-demographic characteristics, anthropometric measurements, dietary intake and fasting blood (collected from 116 and 145 children at 1 and 3 years, respectively) for growth factor analysis (insulin-like growth factor (IGF)-1, IGF binding protein (BP)-1, IGFBP-3, leptin, glucose and insulin). At 1 year it was found that stunted children had lower leptin levels while their IGFBP-1 levels were higher than that in normal children. These differences were, however, not observed at 3 years. Furthermore at 1 year the biochemical parameters were more related to length measures whereas at 3 years the parameters were more associated with weight measures. The observed stunting in this group of children may be a result of chronic undernutrition resulting in long-term growth faltering which is already evident at 1 year. Thus the observed phenomenon might be an adaptive mechanism adopted by children's metabolic processes as they grow up in an environment with inadequate essential nutrients due to poor weaning practices and consumption of a diet of poor quality, resulting in them gaining more weight at the expense of linear growth.

Habitual physical activity and body composition of black township adolescents residing in the North West Province, South Africa.

OBJECTIVE: It is known that stunting and obesity affect a large proportion of children in the world, and these can be affected by the physical activity levels of the children. In the present study, we evaluated the association between physical activity, physical development and body composition in black adolescent children. DESIGN: Cross-sectional study. SETTING: Black township schools in the North West Province, South Africa. METHODS: Three-hundred and thirteen grade 8 children were included in the Physical Activity in Youth study. Anthropometric measurements, body composition measures and maturity level as assessed by Tanner stages were determined in these children. In addition, Previous Day Physical Activity Recall questionnaires were administered on the children to record the various activities they undertake daily. RESULTS: The demographic characteristics of the children showed a high level of homogeneity. A high prevalence of stunting (16.3%) was observed in the children, which was higher in boys than in girls (21.6 vs. 12.3%). Also prevalent was overweight/obesity (8.6%), but this was higher in girls than in boys (13.4 vs. 1.6%). The children also showed a reduction in levels of physical activity with advancement in maturity; furthermore, boys showed a more central form of fat deposition whilst girls showed more gynoid deposition. CONCLUSIONS: The study revealed that physical activity plays a role in determining body composition, and further indicated that physical activity is associated with favourable body composition measures. Children who were more active were likely to have less fat deposits.

Prevalence of gestational diabetes mellitus and the effect of weight on measures of insulin secretion and insulin resistance in third-trimester pregnant rural women residing in the Central Region of Limpopo Province, South Africa.

AIMS: To examine the prevalence of gestational diabetes in third-trimester pregnant women as well as to assess their insulin secretion and insulin resistance (IR). METHODS: Third-trimester pregnant women (n= 262) attending antenatal care at local clinics in the central region of the Limpopo Province underwent a 2-h oral glucose tolerance test (OGTT) with blood collected at 0, 30 and 120 min. Glucose and insulin were measured. RESULTS: The prevalence of gestational impaired glucose tolerance (GIGT) and gestational diabetes mellitus (GDM) was 8.8% (7.3% GIGT; 1.5% GDM). Women with GIGT/GDM were significantly older and had more children compared with women with a normal response to the OGTT. Homeostasis model assessment(HOMA)-IR and fasting insulin were lower in the GIGT/GDM group compared with the normal group, as were measures of insulin secretion (HOMA B-cell function and insulinogenic index). Furthermore, women with body mass index (BMI)> or =30.0 kg/m2 were significantly older and had higher parity, systolic and diastolic blood pressure measurements than those with BMI 25.0-29.9 kg/m2 and BMI < 25.0 kg/m2. However,increased BMI was not associated with an increased risk of GIGT/GDM. CONCLUSION: The present study shows that there is a high prevalence of GIGT/GDM, with most women having IGT. The GIGT/GDM present in these women is characterized by increased insulin sensitivity accompanied by reduced pancreatic B-cell function. Additionally, heavier women appear to have increased first phase insulin secretion, suggesting the presence of insulin resistance.