Abstract:The rising prevalence of obesity and excessive adiposity are global public health concerns. Understanding determinants of changes in adiposity over time is critical for informing effective evidence-based prevention or treatment. However, limited information is available to achieve this objective. Cultural, demographic, environmental, and behavioral factors including socio-economic status (SES) likely account for obesity development. To this end, we related these variables to anthropometric measures in 1058 black adult Tswana-speaking South Africans who were HIV negative in a prospective study over five years. Body mass index (BMI) and waist circumference increased in both sexes, whereas triceps skinfold thickness remained the same. Over the five years, women moved to higher BMI categories and more were diagnosed with central obesity. Age correlated negatively, whereas SES, physical activity, energy, and fat intake correlated positively with adiposity markers in women. In men, SES, marital status, physical activity, and being urban predicted increases in adiposity. For women, SES and urbanicity increased, whereas menopause and smoking decreased adiposity. Among men, smokers had less change in BMI than those that never smoked over five years. Our findings suggest that interventions, focusing on the urban living, the married and those with the highest SES-the high-risk groups identified herein-are of primary importance to contain morbidity and premature mortality due to obesity in black South Africans.

Although studies have suggested that milk and milk-product consumption may influence growth during childhood and puberty, results are inconsistent. This meta-analysis was performed to evaluate the available evidence of randomized controlled trials (RCTs) assessing whether milk and milk-product consumption could affect growth and body composition among children and adolescents aged 6-18 y. PubMed, EMBASE, Web of Science, and The Cochrane Library databases were systematically searched for all RCTs published up to December 2017 that investigated milk and milk-product consumption (≥12 wk) on growth and body composition among participants (aged 6-18 y) without undernourishment or diseases. Study screening and data extraction by 2 reviewers followed established PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The Cochrane Collaboration's tool was used to assess the quality of the trials. Data were pooled using a random-effects model. Seventeen trials with 2844 children and adolescents were included. Milk and milk-product interventions resulted in a greater increase in body weight (0.48 kg; 95% CI: 0.19, 0.76 kg; P = 0.001), lean mass (0.21 kg; 95% CI: 0.01, 0.41 kg; P = 0.04), and attenuated gain in percentage body fat (−0.27%; 95% CI: −0.45%, −0.09%; P = 0.003) compared with control groups. However, there were no significant changes in fat mass, height, or waist circumference in the intervention groups compared with the control groups (P ≥ 0.05). In subgroup analyses, the baseline weight and age, and the duration of intervention were associated with the efficacy of milk and milk-product intake on the change in lean mass, percentage body fat, and waist circumference, respectively (test for subgroup differences: P < 0.05). Children and adolescents aged 6-18 y consuming milk and milk products are more likely to achieve a lean body phenotype. This meta-analysis was registered in the International Prospective Register of Systematic Reviews (PROSPERO) as CRD42018086850.

Lean mass and fat mass were positively associated with femoral neck, spine and hip BMDs and negatively associated with fracture risk in urban black South African women. Our finding suggests that increasing lean mass rather than fat mass is beneficial to bone health. Our study emphasises the importance of positive lifestyle changes, intake of calcium from dairy and adequate weight to maintain and improve bone health of postmenopausal women.

Background Intrauterine exposure to maternal vitamin D status &lt;50 nmol/L of serum 25-hydroxyvitamin D (25(OH)D) may adversely impact infant body composition. Whether postnatal interventions can reprogram for a leaner body phenotype is unknown. Objectives The primary objective was to test whether 1000 IU/d of supplemental vitamin D (vs. 400 IU/d) improves lean mass in infants born with serum 25(OH)D &lt;50 nmol/L. Design Healthy term breastfed infants (Montréal, Canada, March 2016–2019) were assessed for serum 25(OH)D (immunoassay) 24-36 h postpartum. Infants with serum 25(OH)D &lt;50 nmol/L at 24-36 h were eligible for the trial and randomized at baseline (1 month postpartum) to 400 (29 males, 20 females) or 1000 IU/d (29 males, 20 females) of vitamin D until 12 months. Infants (23 males, 18 females) with 25(OH)D ≥50 nmol/L (sufficient) formed a non-randomized reference group provided 400 IU/d. Anthropometry, body composition (dual-energy x-ray absorptiometry) and serum 25(OH)D concentrations were measured at 1, 3, 6 and 12 months. Results At baseline, mean serum 25(OH)D concentration in infants allocated to the 400 and 1000 IU/d vitamin D groups were 45.8 ± 14.1 and 47.6 ± 13.4, respectively, and the reference group 69.2 ± 16.4 nmol/L. Serum 25(OH)D concentration increased on average to ≥50 nmol/L in the trial groups at 3 to 12 months. Lean mass varied differently among groups over time; at 12 months it was higher in the 1000 IU/d vitamin D group compared to the 400 IU/d group (7013 ± 904.6 vs. 6690.4 ± 1121.7 g, P = 0.0428), but not the reference (6715 ± 784.6 g, P = 0.19). Whole body fat mass was not different among groups over time. Conclusions Vitamin D supplementation (400 or 1000 IU/d) during infancy readily corrects vitamin D status, whereas 1000 IU/d modestly increases lean mass by 12 months. The long-term implications require further research.