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One- and Two-Year Effects of the Healthy Primary School of the Future on Children's Dietary and Physical Activity Behaviours: A Quasi-Experimental Study.
Bartelink, NHM, van Assema, P, Kremers, SPJ, Savelberg, HHCM, Oosterhoff, M, Willeboordse, M, van Schayck, OCP, Winkens, B, Jansen, MWJ
Nutrients. 2019;11(3)
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Diet and Physical Activity (PA) habits are formed at a young age, and unhealthy habits can lead to childhood obesity and lifelong health problems. Schools are globally recognised as having access to children across all socio-economic backgrounds and to play an important role in influencing healthy habits. This Dutch experimental longitudinal study looks at the impact Primary schools can have on the health of their students by implementing a dedicated Nutrition and PA Program called ‘Healthy Primary Schools for the Future (HPSF), modelled on an American initiative, piloted in 4 schools and 2 control schools. The study tests whether a fully implemented program (focused on Nutrition and PA - including free lunches & daily PA sessions) or a partial program (focused only on PA sessions) influences healthy change in children’s behaviours versus control schools (no program). The data from 1676 children aged 4-12 yrs was used and the study took place over 3 yrs (2015-2017) with a commitment to continue till 2019 where follow-up data could be obtained. The data was collected once a year using parental and child questionnaires. Additional movement data was obtained from accelerometers the children wore for 7 days during each annual measurement week. The results at year 3 show that a combined nutrition and PA program had greatest benefits on improving diet (variety of foods eaten), and reducing unhealthy snacking, and increasing PA. Neither the partial program or control schools displayed positive changes. The researchers reflect that the full program allowed greater involvement from all parties involved (schools, parents, children’s, educational and health partners) which led to changes becoming an integral part of the school routine. Focusing on nutrition and PA together seemed to encourage complementary behavioural changes compared to focusing only on PA.
Abstract
Schools can help to improve children's health. The 'Healthy Primary School of the Future' (HPSF) aims to sustainably integrate health and well-being into the school system. This study examined the effects of HPSF on children's dietary and physical activity (PA) behaviours after 1 and 2 years' follow-up. The study (n = 1676 children) has a quasi-experimental design with four intervention schools, i.e., two full HPSF (focus: nutrition and PA) and two partial HPSF (focus: PA), and four control schools. Accelerometers and child- and parent-reported questionnaires were used at baseline, after 1 (T1) and 2 (T2) years. Mixed-model analyses showed significant favourable effects for the full HPSF versus control schools for, among others, school water consumption (effect size (ES) = 1.03 (T1), 1.14 (T2)), lunch intake of vegetables (odds ratio (OR) = 3.17 (T1), 4.39 (T2)) and dairy products (OR = 4.43 (T1), 4.52 (T2)), sedentary time (ES = -0.23 (T2)) and light PA (ES = 0.22 (T2)). Almost no significant favourable effects were found for partial HPSF compared to control schools. We conclude that the full HPSF is effective in promoting children's health behaviours at T1 and T2 compared with control schools. Focusing on both nutrition and PA components seems to be more effective in promoting healthy behaviours than focusing exclusively on PA.
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Effects of Two Years of Calorie Restriction on Aerobic Capacity and Muscle Strength.
Racette, SB, Rochon, J, Uhrich, ML, Villareal, DT, DAS, SK, Fontana, L, Bhapkar, M, Martin, CK, Redman, LM, Fuss, PJ, et al
Medicine and science in sports and exercise. 2017;49(11):2240-2249
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Caloric restriction (CR) has been shown to increase lifespan and delay age-related disease in many species. As a part of the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) study, this particular study aimed to determine whether long-term CR adversely affects aerobic capacity and muscle strength in 218 healthy, nonobese adults. Participants were randomised to 25% CR or control group, and a VO2max treadmill test, knee flexor and extensor strength were all measured at baseline, one year and two years. This study showed that two years of CR without a structured exercise component did not appear to compromise aerobic capacity in healthy nonobese adults.
Abstract
PURPOSE Calorie restriction (CR) improves health span and delays age-related diseases in many species. The multicenter Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) study was the first randomized controlled trial of CR in nonobese humans. The aim of this investigation was to determine the effects of CR on V˙O2max and muscle strength in the CALERIE trial. METHODS Healthy, normal-weight, and mildly overweight women and men (n = 218, mean ± SE age = 37.9 ± 0.5 yr) were randomized to 25% CR or an ad libitum (AL) control condition in a 2:1 allocation (143 CR, 75 AL). V˙O2max was determined with an incremental treadmill test; the strength of the knee flexors and extensors was assessed by dynamometry at baseline, 1 yr, and 2 yr. RESULTS The CR group achieved an average 11.9% ± 0.7% CR during the 2-yr intervention. Body weight decreased in CR (-7.7 ± 0.4 kg), but not AL (+0.2 ± 0.5 kg). Absolute V˙O2max (L·min) decreased at 1 and 2 yr with CR, whereas V˙O2max expressed relative to body mass increased at both time points (1 yr: +2.2 ± 0.4; 2 yr: +1.9 ± 0.5 mL·kg·min) and relative to AL. The CR group increased their treadmill test time and workload at 1 and 2 yr. Strength results in CR were similar, with decreases in absolute flexor and extensor strength, but increases when expressed relative to body mass. No changes were observed for V˙O2max expressed relative to lean body mass or leg lean mass. CONCLUSIONS Two years of modest CR without a structured exercise component did not appear to compromise aerobic capacity in healthy nonobese adults. The clinical implications of the observed changes in V˙O2max and muscle strength will be important to explore in future studies.
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Association Between Single Gene Polymorphisms and Bone Biomarkers and Response to Calcium and Vitamin D Supplementation in Young Adults Undergoing Military Training.
Gaffney-Stomberg, E, Lutz, LJ, Shcherbina, A, Ricke, DO, Petrovick, M, Cropper, TL, Cable, SJ, McClung, JP
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research. 2017;32(3):498-507
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The risk of stress fracture is increased in initial military training (IMT) largely because of unaccustomed activity, resulting in a change in calcium and vitamin D levels. Genetic polymorphisms are variations in a gene that affect the level of gene expression, and bone metabolism and absorption is impacted by this. The primary aim of this randomised, double-blind, placebo controlled trial was to determine whether genes related to Calcium and vitamin D were associated with markers of bone metabolism in 748 young adults entering military training. Participants were randomised to consume bars between meals that were either supplemented with Calcium and vitamin D or placebo that were matched in taste and appearance. Fasting blood samples were taken before and after the 7- to 9-week IMT programme to assess circulating biomarkers and genes. This study found that genetic polymorphisms related to Calcium and vitamin D were associated with vitamin D status and markers of bone metabolism. It also found that genes could predict change in vitamin D absorption levels. Based on these results, the authors conclude this study provides novel insight that helps further understanding between genetics, environment and bone metabolism.
Abstract
Initial military training (IMT) is associated with increased stress fracture risk. In prior studies, supplemental calcium (Ca) and vitamin D provided daily throughout IMT reduced stress fracture incidence, suppressed parathyroid hormone (PTH), and improved measures of bone health compared with placebo. Data were analyzed from a randomized, double-blind, placebo-controlled trial to determine whether single-nucleotide polymorphisms (SNPs) in Ca and vitamin D-related genes were associated with circulating biomarkers of bone metabolism in young adults entering IMT, and whether responses to Ca and vitamin D supplementation were modulated by genotype. Associations between SNPs, including vitamin D receptor (VDR), vitamin D binding protein (DBP), and 1-alpha-hydroxylase (CYP27B1), and circulating biomarkers were measured in fasting blood samples from volunteers (n = 748) starting IMT. Volunteers were block randomized by race and sex to receive Ca (2000 mg) and vitamin D (1000 IU) or placebo daily throughout Army or Air Force IMT (7 to 9 weeks). Total Ca and vitamin D intakes were calculated as the sum of supplemental intake based on intervention compliance and dietary intake. Relationships between SNPs, Ca, and vitamin D intake tertile and change in biomarkers were evaluated in trial completers (n = 391). At baseline, the minor allele of a DBP SNP (rs7041) was positively associated with both 25OHD (B = 4.46, p = 1.97E-10) and 1,25(OH)2 D3 (B = 9.63, p < 0.001). Combined genetic risk score (GRS) for this SNP and a second SNP in the VDR gene (rs1544410) was inversely associated with baseline 25OHD (r = -0.28, p < 0.001) and response to Ca and vitamin D intake differed by GRS (p < 0.05). In addition, presence of the minor allele of a second VDR SNP (rs2228570) was associated with lower P1NP (B = -4.83, p = 0.04) and osteocalcin (B = -0.59, p = 0.03). These data suggest that VDR and DBP SNPs are associated with 25OHD status and bone turnover and those with the highest GRS require the greatest vitamin D intake to improve 25OHD during IMT. © 2016 American Society for Bone and Mineral Research.