Relationships between different nutritional anthropometric statuses and health-related fitness of South African primary school children.

BACKGROUND: A double burden of both under- and over-nutrition exists among South African children. AIM: To describe associations between nutritional statuses and health-related fitness test performances. SUBJECTS AND METHODS: Height and weight of 10 285 children (6-13 years; n = 5604 boys and 4681 girls) were measured and used to calculate body mass index (BMI) and prevalence of overweight and obesity, stunting, wasting and underweight. Physical fitness scores for standing long jump, shuttle run, sit-and-reach, sit-up (EUROFIT) and cricket ball throw were assessed. Age- and gender-specific z-scores were calculated for these variables. Physical fitness for each nutritional status group was compared to children of normal weight. RESULTS: Compared to normal weight children, overweight and obese children scored lower on all fitness tests (p < .001), except cricket ball throw (p = .235) and sit-and-reach (p = .015). Stunted and underweight children performed poorer than normal weight children on most fitness tests (p < .001), except sit-and-reach (stunted: p = .829; underweight: p = .538) and shuttle run (underweight: p = .017). Performance of wasted children was not as highly compromised as other under-nourished groups, but they performed poorer on the cricket ball throw (p < .001). CONCLUSIONS: When compared to normal weight children, both under- and over-nourished children performed poorer on some, but not all, health-related fitness tests.

Shift work and chronic disease: the epidemiological evidence.

BACKGROUND: Shift work, including night work, has been hypothesized to increase the risk of chronic diseases, including cancer, cardiovascular disease (CVD), metabolic syndrome and diabetes. Recent reviews of evidence relating to these hypotheses have focussed on specific diseases or potential mechanisms, but no general summary of the current data on shift work and chronic disease has been published. METHODS: Systematic and critical reviews and recent original studies indexed in PubMed prior to 31 December 2009 were retrieved, aided by manual searches of reference lists. The main conclusions from reviews and principle results from recent studies are presented in text and tables. RESULTS: Published evidence is suggestive but not conclusive for an adverse association between night work and breast cancer but limited and inconsistent for cancers at other sites and all cancers combined. Findings on shift work, in relation to risks of CVD, metabolic syndrome and diabetes are also suggestive but not conclusive for an adverse relationship. CONCLUSIONS: Heterogeneity of study exposures and outcomes and emphasis on positive but non-significant results make it difficult to draw general conclusions. Further data are needed for additional disease endpoints and study populations.

Secular trends in the prevalence of stunting, overweight and obesity among South African children (1994-2004).

BACKGROUND/OBJECTIVES: Various nutrition programs and free health care for children less than 6 years old were introduced in South Africa in the mid-1990s. We aim to describe secular trends for nutritional status of South African (SA) children in the 10-year period following these reforms. SUBJECTS/METHODS: The SA National Primary Schools' Anthropometric Survey (n=105 000) is a cross-sectional survey of children from all SA Education Departments sampled during 1994. The Health of the Nation Study (n=10 295) is a cross-sectional study, including children from primary schools in five SA Provinces sampled from 2001 to 2004. Height and weight of SA children were measured during both surveys. In 8-11 year olds, the National Centre for Health Statistics reference was used to calculate the prevalence of mild and moderate stunting, and overweight and obesity were calculated according to the International Obesity Task Force reference. Coexistence of stunting, overweight and obesity among these two age- and sex-matched cohorts were also calculated. RESULTS: When compared with previous SA data, moderate stunting (24.6-4.9%, P<0.001) decreased over the 7-10 years considered, whereas overweight (1.2-13.0%, P<0.001) and obesity (0.2-3.3%, P<0.001) prevalence increased. There were lower levels of mild stunting and similar levels of moderate stunting among overweight/obese children when compared with non-overweight/non-obese children. CONCLUSIONS: Our findings suggest that feeding policies may have been effective in reducing the prevalence of under-nutrition. However, inter-sectoral policies should recognize the apparent secular trend for an increased prevalence in overweight/obesity among young South Africans.

Obesity and overweight in South African primary school children -- the Health of the Nation Study.

OBJECTIVES: To determine the prevalence of overweight and obesity in a sample of South African children aged 6 - 13 years. DESIGN: Random sampling of schools within each provincial and socio-economic category. SETTING: Primary school children from 5 South African provinces. SUBJECTS: 10 195 (5 611 male and 4 584 female) primary school children. OUTCOME MEASURE: Height and weight were measured and body mass index (BMI) (weight (kg)/height (m) (2)) was calculated for each grouping (age x gender x ethnic group). Cut-off points for BMI defining obese and overweight for gender and age (6 - 13 years) were calculated in accordance with international standards. RESULTS: There were significant differences in height and mass between the different ethnic groups and genders. This trend was not evident for the BMI values. The prevalence of obesity within the sample was 3.2% for boys and 4.9% for girls, whereas overweight prevalence was 14.0% for boys and 17.9% for girls. When the contribution of each ethnic group was adjusted to the demographics of South Africa these values were only slightly different. The prevalence of obesity and overweight among boys was 2.4% and 10.9% respectively, while obese and overweight girls comprised 4.8% and 17.5%, respectively. CONCLUSIONS: South African children show trends of obesity and overweight, similar to values in developed countries about 10 years ago. Intervention strategies to combat an increasingly sedentary lifestyle may need to be developed for the South African context.