Relationships between Iron Status and Selected Physical Fitness Components of South African Adolescents: The PAHL-Study.

Poor iron status is detrimental to physical and cognitive performance in adolescents. Due to the limited studies investigating the association between iron status and physical fitness components in adolescents from low- and middle-income countries, we aimed to determine the association of iron status with selected physical fitness components in South African adolescents. A cross-sectional study design, including 178 adolescents (102 girls and 76 boys) from the Physical Activity and Health Longitudinal Study (PAHLS), was followed. Height and weight were measured to calculate the body mass index (BMI). Subsequently, WHO BMI-for-age-specific categorised body fatness. Cardiorespiratory fitness was determined with a 20-m shuttle run test (V˙O2max), and lower-body explosive power by the standing broad jump (SBJ). Fasting haemoglobin (Hb) and ferritin were analysed from blood samples. Correlation analyses determine the association between iron status, explosive power and cardiorespiratory fitness. Of the 178 participants, 18.5% (n = 33) had low Hb, and 14% (n = 25) iron deficiency without anaemia. Significant positive correlations were found between the selected physical fitness components, ferritin, and Hb. In boys, a positive association was found between Hb and SBJ (r = 0.30, p = 0.006), whilst in girls, positive associations were found between ferritin (r = 0.25, p = 0.04) and SBJ, and Hb with both SBJ (r = 0.21, p = 0.03) and V˙O2max (r = 0.32, p = 0.001). Hb concentration remained associated with V˙O2max and SBJ in girls after adjustment for age, whilst in boys, Hb concentration was associated with SBJ. Higher iron status in South African adolescents is associated with higher lower-limb explosive power and cardiorespiratory fitness. We suggest monitoring of haematological parameters, and interventions to improve the iron status of South African adolescents.

Assessment of non-communicable disease risk factors, functional performance, and health-related quality of life in adults: a comparative analysis in low-resourced urban and rural areas of South Africa.

BACKGROUND: Globally, disparities between non-communicable disease (NCD) risk factors, functional performance, and health-related quality of life (HRQoL) exist in people living in rural and low-resourced urban settings. Evidence of these health differences determined with objective NCD risk factors and functional performance measurements in South Africa, is scarce. Therefore, the study aimed to determine the differences in NCD risk factors, functional performance and HRQoL between rural and low-resourced urban areas. METHODS: The study recruited 311 adults (35-80 years) presenting with at least one NCD risk factor from low-resourced urban- (n = 183) and rural (n = 128) communities. Objective measurements of physical activity (PA) by means of combined heart rate and accelerometery, body composition employing skinfolds, peripheral lipid and glucose concentrations, blood pressure, functional performance indicators (handgrip, single leg stand, sit-to-stand, timed-up-and-go speed, predicted peak VO2 max); and HRQoL were measured according to standard procedures. Independent t-tests, Mann-Whitney U, and chi-square tests were performed to determine differences between the variables of low-resourced urban and rural settings. RESULTS: The participants from the low-resourced urban setting were significantly older than the rural residents (59.1 ± 10.7 years vs. 52.8 ± 11.3 years; p = 0.001). NCD risk factors were significantly more prevalent in the low-resourced urban participants compared to rural participants, in particular for elevated systolic (85.8% vs. 62.5%; p = 0.001), and diastolic blood pressure (88.5% vs. 65.6%; p = 0.001), physical inactivity (95.9% vs. 87.7%; p = 0.026), increased cholesterol concentrations (22.1% vs. 8.7%; p = 0.002), and increased waist circumference (61.9% vs. 49.2%; p = 0.027). Low-resourced urban residents presented with a higher average body fat percentage (27.69% ± 7.65% vs. 12.23% ± 4.67%; p < 0.001), and lower moderate to vigorous PA levels (37.19 ± 49.55 [95% CI = 29.12-45.27] vs. 62.92 ± 60.43 min/week [95% CI = 47.95-77.90]; p = 0.003) compared to rural residents. Rural residents showed significantly better functional performance, including peak VO2 (23.99 ± 9.89 vs. 16.95 ± 7.64 ml/min/kg; p = 0.001) and single leg stand (right leg: 44.96 ± 18.47 vs. 20.87 ± 19.18 s; p = 0.001) as well as higher HRQoL for the physical (51.06 ± 8.14% vs. 45.62 ± 11.13%; p < 0.001) and mental (54.75 ± 8.24% vs. 48.91 ± 12.27%; p < 0.001) component scores compared to participants from the low-resourced urban areas. CONCLUSION: NCD risk factors, functional performance, and HRQoL significantly differ in rural communities compared to low-resourced urban communities in South Africa. Urban areas' most prevalent risk factors were elevated blood pressure, physical inactivity, and increased waist circumference. Participants from rural areas demonstrated significantly better functional performance, such as fitness and balance. HRQoL was better in rural settings than in urban settings. Future intervention programmes should be tailored for specific settings.

The relationship between physical activity, body fatness and metabolic syndrome in urban South African school teachers: The sympathetic activity and ambulatory blood pressure in Africans study.

BACKGROUND:  Globally, the prevalence of metabolic syndrome (MS) is rising because of increased levels of physical inactivity and obesity. In South Africa, information about teachers' physical activity (PA), body fatness and MS is limited. AIM:  To assess the relationship between PA, body fatness and MS in urban South African teachers. SETTING:  The study setting was in Dr Kenneth Kaunda District in the North West province of South Africa. METHODS:  A cross-sectional study was conducted using secondary data drawn from the sympathetic activity and ambulatory blood pressure in Africans (SABPA) study of 216 teachers (aged 25-65 years). Variables included anthropometry, biochemical measurements, objectively measured PA and lifestyle behaviours. RESULTS:  Twenty-nine percent of the total participants were classified with MS, with 46% in men compared to 13% in women; 33% were sedentary and 67% participated in light activity. A weak significant negative relationship was found between the mean 7-day awake metabolic equivalent of tasks (METs) and triglycerides (r = -0.29; p = 0.02) and gamma-glutamyl transferase (r = -0.25; p = 0.06), activity energy expenditure (r = -0.24; p = 0.06) and PA level (r = -0.23; p = 0.07). After adjusting for age, self-reported smoking and alcohol use or consumption, a weak significant negative relationship between mean 7-day awake METs and triglycerides (r = -0.28; p  0.01) was observed. CONCLUSION:  In the teachers with MS, only one MS marker (triglycerides) showed a negative association with PA. Physical activity could therefore be beneficial in the regulation of triglycerides. Participation in regular PA could be beneficial in the regulation of triglycerides. Focused PA interventions in school teachers that advocate the benefits of PA and healthy lifestyle choices to reduce dietary fat intake (and alcohol) are recommended.

The Role of Physical Activity Status in the Relationship between Obesity and Carotid Intima-Media Thickness (CIMT) in Urban South African Teachers: The SABPA Study.

Globally, the prevalence of physical inactivity and obesity are on the rise, which may increase carotid intima-media thickness (CIMT) as a marker of subclinical atherosclerosis. This study assessed the association between physical activity (PA), obesity, and CIMT. A cross-sectional study design was used, including a sub-sample (n = 216) of teachers who participated in the Sympathetic Activity and Ambulatory Blood Pressure in Africans (SAPBA) study. Measurements included the following: physical activity status (measured with ActiHeart devices over 7 consecutive days), body mass index (BMI), waist circumference (WC), waist-to-height ratio (WtHR), CIMT (measured by SonoSite Micromax ultrasound), blood pressure (BP), fasting C-reactive protein (CRP), and cholesterol and glucose levels. Data were analysed using the Statistical Package for Social Science. One-third of the teachers were physically inactive (33%) and had low-grade inflammation CRP ≥ 3 mg/L (41%). Males were more sedentary and had higher BP and CIMT (p < 0.05). Independent of age and sex, WC or central obesity was 2.63 times more likely (p = 0.02) to contribute to atherosclerosis, especially in females (OR: 4.23, p = 0.04). PA levels were insignificantly and negatively (ß −0.034; 0.888; 0.240) related to subclinical atherosclerosis. The cardiovascular disease risk profiles and limited PA status may have curbed the beneficial impact of PA on the obesity and atherosclerosis.

Correction: Relationship between physical activity and carotid intima-media thickness among teachers in South Africa: the SABPA study.

In the Abstract, in Methods: Ultrasound CIMT imaging was done using the SonoSite Micromaxx. Physical activity was done over seven consecutive days. In the Abstract, in Results: The prevalence of obesity according to BMI and sedentary behaviour was above 30%; hypertension was 38.9% and low-grade inflammation (CRP) was 41.1%.

Relationship between physical activity and carotid intima-media thickness among teachers in South Africa: the SABPA study.

OBJECTIVE: To determine the relationship between objectively measured physical activity (PA) and carotid intima-media thickness (CIMT) in teachers in South Africa. METHODS: A cross-sectional study was conducted among 215 teachers aged 25 to 65 years (mean age 49.67 ± 8.43 years) who participated in the Sympathetic Activity and Ambulatory Blood Pressure in Africans (SABPA) prospective cohort study. CIMT was measured using the SonoSite Micromaxx ultrasound over seven consecutive days. Other measurements obtained included body mass index (BMI), waist circumference, 24-hour ambulatory blood pressure, and C-reactive protein (CRP) and fasting blood total cholesterol levels. Data were analysed using Statistical Package for Social Sciences (SPSS) version 25. RESULTS: The prevalence of obesity according to BMI and sedentary behaviour was above 30%; hypertension was 38.9% and CRP 41.1 mg/dl. Male teachers showed higher mean values for CIMT than female teachers (0.75 ± 0.16 vs 0.66 ± 0.12 mm; p ≤ 0.05). A borderline negative association existed between CIMT and mean seven-day awake metabolic equivalent of task (r = -0.19; p = 0.08) in female teachers in the light-PA group. CIMT was inversely associated with total energy expenditure (r = -0.31; p = 0.05) in sedentary male teachers. CONCLUSIONS: Participation in light PA was associated with lower CIMT values in female teachers. Given the health implications of cardiovascular disease risk among teachers, PA intervention studies are recommended to determine effective interventions to provide information on how to decrease the progression of subclinical atherosclerosis in this population.