Physical activity and obesity prevention

Randomized Trial to Improve Body Composition and Micronutrient Status Among South African Children

INTRODUCTION

Physical activity (PA) promotion combined with multimicronutrient supplementation (MMNS) among school-age children may reduce fat mass accrual and increase muscle mass through different mechanisms and so benefit child health. This study determined the efficacy of combined interventions on body composition among South African schoolchildren and determined if micronutrients mediate these effects.

STUDY DESIGN

Longitudinal cluster randomized controlled trial of children followed from 2019 to 2021. Statistical analyses carried from 2022 to 2023.

SETTING/PARTICIPANTS

A total of 1,304 children 6-12 years of age recruited from public schools in Gqeberha, South Africa.

INTERVENTION

Children were randomized by classes to either: (a) a physical activity group (PA); (b) a MMNS group; (c) a physical activity + multimicronutrient supplementation group (PA + MMNS); and (d) a placebo control group.

MAIN OUTCOME MEASURES

Trajectories of overall and truncal fat free mass (FFM) and fat mass (FM) estimates in modeled at 9 and 21 months using latent growth curve models (LGCM). Changes in micronutrient concentrations at 9 months from baseline.

RESULTS

An increased FFM trajectory was found among children in the MMNS arm at 9 months (Beta 0.16, 95% CI = 0.12, 0.31). The PA and MMNS arms both had positive indirect effects on this trajectory at 9 months (Beta 0.66, 95% CI = 0.44, 0.88 and Beta 0.32 95% CI = 0.1 0.5, respectively) and similarly at 21 months when mediated by zinc concentration changes. A reduced FM trajectory was found among children in the PA promotion arm at 9 months when using this collection point as the referent intercept. This arm was inversely associated with the FM trajectory at 9 months when mediated by zinc changes.

CONCLUSIONS

PA and MMNS promotion in school-based interventions directly contributed to reductions in FM and increased FFM among South African children and indirectly through changes in micronutrient status.

TRIAL REGISTRATION

ISRCTN, ISRCTN29534081. Registered on August 9, 2018 Institutional review board: Ethikkommission Nordwest- und Zentralschweiz" (EKNZ, project number: Req-2018-00608). Date of approval: 2018.

Association of physical activity with increased PI3K and Akt mRNA levels in adipose tissues of obese and non-obese adults

Phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathway regulates glucose and lipid metabolism. We examined the association of PI3K and Akt expression in visceral (VAT) and subcutaneous adipose tissue (SAT) with daily physical activity (PA) in non-diabetic obese and non-obese adults. In this cross-sectional study, we included 105 obese (BMI ≥ 30 kg/m²) and 71 non-obese (BMI < 30 kg/m²) subjects (aged/ ≥ 18 years). PA was measured using a valid and reliable International Physical Activity Questionnaire(IPAQ)-long-form, and the metabolic equivalent of task(MET) was calculated. Real-time PCR was performed to analyze the mRNA relative expression. VAT PI3K expression had a lower level in obese compared to non-obese (P = 0.015), while its expression was higher in active individuals than inactive ones (P = 0.029). SAT PI3K expression was increased in active individuals compared to inactive ones (P = 0.031). There was a rise in VAT Akt expression in the actives compared to the inactive participants (P = 0.037) and in non-obese/active compared to non-obese/inactive individuals (P = 0.026). Obese individuals had a decreased expression level of SAT Akt compared to non-obsesses (P = 0.005). VAT PI3K was directly and significantly associated with PA in obsesses (β = 1.457, P = 0.015). Positive association between PI3K and PA suggests beneficial effects of PA for obese individuals that can be partly described by PI3K/Akt pathway acceleration in adipose tissue.

Vigorous-intensity exercise as a modulator of cardiac adipose tissue in women with obesity: a cross-sectional and randomized pilot study

Cardiac adipose tissue (CAT) has become an important target for the reduction of disease risk. Supervised exercise programs have shown potential to "significantly" reduce CAT; however, the impact of different exercise modalities is not clear, and the relationships between CAT, physical activity (PA) levels and fitness (PFit) remain unknown. Therefore, the purpose of this study was to analyze the relationships between CAT, PA and PFit, and to explore the effects of different exercise modalities in a group of women with obesity. A total of 26 women (age: 23.41 ± 5.78 years-old) were enrolled in the cross-sectional study. PA, cardiorespiratory fitness, muscular strength, body composition and CAT were evaluated. The pilot intervention included 16 women randomized to a control (CON, n=5), high intensity interval training (HIIT, n = 5) and high-intensity circuit training (HICT, n=6) groups. Statistical analysis showed negative correlations between CAT and vigorous PA (VPA) (r _s=-0.41, p=0.037); and between percent body fat (%BF), fat mass (FM), and all PA levels (r _s=-0.41- -0.68, p<0.05); while muscle mass was positively associated with moderate-to-vigorous PA, and upper-body lean mass with all PA levels (r _s =0.40-0.53, p<0.05). The HICT intervention showed significant improvements (p<0.05) in %BF, FM, fat free mass, and whole-body and lower extremities lean mass and strength after three weeks; however, only leg strength and upper extremities' FM improved significantly compared to CON and HICT. In conclusion, although all types of PA showed a positive influence on body fat content, only VPA significantly impacted on CAT volume. Moreover, three weeks of HICT induced positive changes in PFit in women with obesity. Further research is needed to explore VPA levels and high-intensity exercise interventions for short- and long-term CAT management.

The most effective exercise to prevent obesity: A longitudinal study of 33,731 Taiwan biobank participants

Regular physical exercise is recommended to reduce the risk of obesity. However, it remains unclear which activities are more effective in preventing obesity. In this study, five obesity indices and lifestyle factors of 33,731 Taiwan Biobank adults were measured/collected twice with a mean time interval of 4.06 years. A linear mixed effects model was fitted to assess the associations of exercises with obesity indices, in which a random intercept term was used to account for individual differences. The five obesity indices included body mass index (BMI), body fat percentage (BFP), waist circumference (WC), hip circumference (HC), and waist-hip ratio (WHR). Among 23 exercises, jogging and yoga were consistently the most effective choices across all five obesity indices. One more weekly hour to jog was associated with a 0.093 kg/m2 decrease in BMI (p = 4.2E-20), a 0.297% decrease in BFP (p = 3.8E-36), a 0.398 cm decrease in WC (p = 1.6E-21), and a 2.9E-3 decrease in WHR (p = 1.3E-17). One more weekly hour to perform yoga was associated with a 0.225 cm decrease in HC (p = 6.4E-14). Jogging is an exercise for the entire body. Arms swing, waist turn, legs and feet run, and shoulders and abdomen are also involved in this act. By contrast, many yoga poses use muscles around the hips and pelvis, and therefore yoga is the most effective exercise to reduce HC.

Impact of a school-based health intervention program on body composition among South African primary schoolchildren: results from the KaziAfya cluster-randomized controlled trial

BACKGROUND

The prevalence of overweight and obesity is increasing among African children potentially predisposing them to greater obesity and non-communicable diseases (NCDs) in adulthood. This risk may be higher among growth-impaired children who may have greater fat mass. Therefore, we examined the effects of school-based physical activity (PA) promotion and multi-micronutrient supplementation (MMNS) on body composition among South African children enrolled in a longitudinal school-based randomized controlled trial.

METHODS

Children were cluster-randomized by class to one of four groups: (a) a physical activity group (PA), (b) a multi-micronutrient supplementation group (MMNS), (c) a physical activity + multi-micronutrient supplementation group (PA + MMNS), and (d) control group, and were being followed for 3 years. Linear random effects regression models with random intercepts for school classes tested the associations of each intervention arm with overall fat mass (FM), fat-free mass (FFM), truncal fat mass (TrFM), and truncal fat-free mass (TrFFM) at 9 months (T2) for boys and girls. These differences were then explored among children who differed in height velocity (HV).

RESULTS

A total of 1304 children (614 girls, 667 boys) in twelve clusters were assessed at baseline and after 9 months follow-up (T2). At baseline, approximately 15% of children were classified as overweight or obese while approximately 38% of children were classified as mildly stunted or moderately/severely stunted. Among girls, promotion of PA was associated with reduced FM and TrFM at T2 while MMNS was associated with increased FFM. Children with reduced HV in the PA arm had reduced FM while children in the MMNS arm with lower HV had increased FM compared to children in the control arm. Similarly, children with lower HV in the MM and PA groups had reduced TrFM compared to children in the control arm.

CONCLUSIONS

Our study suggests that the promotion of school-based physical activity programs and micronutrient supplementation can reduce childhood adiposity and so reduce the risk of obesity and chronic diseases later in adulthood.

TRIAL REGISTRATION

ISRCTN, ISRCTN29534081 . Registered on August 9, 2018. The trial was designed, analyzed, and interpreted based on the CONSORT protocol (Additional file 1: CONSORT checklist for randomized trial).

Physical activity in the management of obesity in adults: A position statement from Exercise and Sport Science Australia

This Position Statement examines the evidence for physical activity in weight and adiposity loss, prevention of weight and adiposity gain, and in weight regain in adults, and provides guidance on implications for exercise practitioners. Research evidence indicates that >150 min but preferably 300 min per week of aerobic activity of at least moderate intensity is required to prevent weight and adiposity gain, and at least the upper end of this range of activity to prevent weight regain after weight loss. For meaningful weight and total adiposity loss, a minimum of 300-420 min per week of aerobic activity of at least moderate intensity is required. The evidence around the volume of aerobic physical activity required to reduce central adiposity is emerging, and research suggests that it may be substantially less than that required for weight loss. The impact of high-intensity physical activity and resistance exercise for weight management is uncertain. During consultations for weight management, exercise practitioners should advise that metabolic and cardiovascular health benefits can be achieved with physical activity at any weight, and irrespective of weight change.

Physical Activity and Self-Reported Metabolic Syndrome Risk Factors in the Aboriginal Population in Perth, Australia, Measured Using an Adaptation of the Global Physical Activity Questionnaire (GPAQ)

Background: Complex, ongoing social factors have led to a context where metabolic syndrome (MetS) is disproportionately high in Aboriginal Australians. MetS is characterised by insulin resistance, abdominal obesity, hypertension, hypertriglyceridemia, high blood-sugar and low HDL-C. This descriptive study aimed to document physical activity levels, including domains and intensity and sedentary behaviour, and MetS risk factors in the Perth Aboriginal (predominately Noongar) community. Methods: The Global Physical Activity Questionnaire (GPAQ), together with a questionnaire on self-reported MetS risk factors, was circulated to community members for completion during 2014 (n = 129). Results: Data were analysed using chi-squared tests. The average (SD) age was 37.8 years (14) and BMI of 31.4 (8.2) kg/m2. Occupational, transport-related and leisure-time physical activity (PA) and sedentary intensities were reported across age categories. The median (interquartile range) daily sedentary time was 200 (78, 435), 240 (120, 420) and 180 (60, 300) minutes for the 18-25, 26-44 and 45+ year-olds, respectively (p = 0.973). Conclusions: An in-depth understanding of the types, frequencies and intensities of PA reported for the Perth Aboriginal community is important to implementing targeted strategies to reduce the prevalence of chronic disease in this context. Future efforts collaborating with community should aim to reduce the risk factors associated with MetS and improve quality of life.

The Role of Exercise, Diet, and Cytokines in Preventing Obesity and Improving Adipose Tissue

The prevalence of obesity continues to rise worldwide despite evidence-based public health recommendations. The promise to adopt a healthy lifestyle is increasingly important for tackling this global epidemic. Calorie restriction or regular exercise or a combination of the two is accepted as an effective strategy in preventing or treating obesity. Furthermore, the benefits conferred by regular exercise to overcome obesity are attributed not only to reduced adiposity or reduced levels of circulating lipids but also to the proteins, peptides, enzymes, and metabolites that are released from contracting skeletal muscle or other organs. The secretion of these molecules called cytokines in response to exercise induces browning of white adipose tissue by increasing the expression of brown adipocyte-specific genes within the white adipose tissue, suggesting that exercise-induced cytokines may play a significant role in preventing obesity. In this review, we present research-based evidence supporting the effects of exercise and various diet interventions on preventing obesity and adipose tissue health. We also discuss the interplay between adipose tissue and the cytokines secreted from skeletal muscle and other organs that are known to affect adipose tissue and metabolism.

Leisure-time physical inactivity and association with body mass index: a Finnish Twin Study with a 35-year follow-up

Background

We investigated the stability and change of leisure-time physical inactivity in adult men and women during a 35-year follow-up. We also analysed the impact of long-term physical inactivity on the development of body mass index (BMI).

Methods

: In this population-based cohort study, 5254 Finnish twin individuals (59% women) participated in four surveys in 1975, 1981, 1990 and 2011. Mean age at baseline was 23.9 years. Individual long-term leisure-time physical activity (LTPA) was categorized into seven classes varying from 'persistently inactive' to 'persistently active'. We used the multivariate multilevel mixed-effects linear regression model and paired-sample t-test in the analyses. Co-twin control design was used for examining within-pair associations.

Results

: Of men 11%, and of women 8%, were persistently inactive. Among both sexes, the mean BMI slope trajectories were steeper among the persistently inactive and those who became inactive than among those who were persistently active. Overall, the inactive participants gained 1.4 kg/m 2 [95% confidence interval (CI) 1.2 to 1.7] more in weight than did the active participants from 1975 to 2011. Among twin pairs discordant for LTPA, the corresponding difference was 1.4 kg/m 2 (95% CI 0.83 to 2.0) in dizygotic pairs and 0.68 kg/m 2 (95% CI 0.05 to1.3) in monozygotic pairs.

Conclusions

Over a 35-year time span from young adulthood, persistently inactive participants and those who had become inactive had greater weight increases than those who were persistently active. This association was also found in twin-pair analyses, although attenuated in monozygotic pairs. This may support the importance of LTPA in weight management, although further causal inference is required.

The "ripple effect": Health and community perceptions of the Indigenous Marathon Program on Thursday Island in the Torres Strait, Australia

ISSUE ADDRESSED

Physical inactivity is a key health risk among Aboriginal and Torres Strait Islander (Indigenous) Australians. We examined perceptions of the Indigenous Marathon Program (IMP) in a remote Torres Strait island community.

METHODS

Semi-structured interviews with community and program stakeholders (n = 18; 14 Indigenous) examined barriers and enablers to running and the influence of the IMP on the community. A questionnaire asked 104 running event participants (n = 42 Indigenous) about their physical activity behaviours, running motivation and perceptions of program impact. Qualitative data were analysed using thematic content analysis, and quantitative data were analysed using descriptive statistics.

RESULTS

Interviews revealed six main themes: community readiness, changing social norms to adopt healthy lifestyles, importance of social support, program appeal to hard-to-reach population groups, program sustainability and initiation of broader healthy lifestyle ripple effects beyond running. Barriers to running in the community were personal (cultural attitudes; shyness) and environmental (infrastructure; weather; dogs). Enablers reflected potential strategies to overcome described barriers. Indigenous questionnaire respondents were more likely to report being inspired to run by IMP runners than non-Indigenous respondents.

CONCLUSIONS

Positive "ripple" effects of the IMP on running and broader health were described to have occurred through local role modelling of healthy lifestyles by IMP runners that reduced levels of "shame" and embarrassment, a common barrier to physical activity among Indigenous Australians. A high initial level of community readiness for behaviour change was also reported. SO WHAT?: Strategies to overcome this "shame" factor and community readiness measurement should be incorporated into the design of future Indigenous physical activity programs.

The association between leisure-time physical activity and lung function in older adults: The English longitudinal study of ageing

The longitudinal association between physical activity and lung function is unclear. Therefore, we examined said association over eight years. This study included data from 2966 participants in English Longitudinal Study of Ageing (63±7years [mean±SD]), a prospective study of initially healthy, community dwelling adults. Physical activity was assessed using an interview and lung function using a spirometer at baseline (2004-5) and follow-up (2012-13). General linear regression was used to assess associations between activity and lung function. Logistic regression was used to assess the odds of new cases of abnormal lung function. Some 14% of participants were defined as physically inactive at baseline, 50% were classified into the moderate group, and 36% into the vigorous group. In comparison with remaining inactive at follow-up, remaining active was positively associated with forced vital capacity (FVC) (β=0.09, 95% confidence interval [CI]: 0.01, 0.17; p=0.02) and forced expiratory volume in one second (FEV-1) (β=0.09, 95% CI: 0.02, 0.15; p=0.01) after adjustment for baseline lung function score and other covariates. Using the fifth centile to define the lower limit of normal (that is, -1.64 z scores), there were lower odds of incident abnormal lung function in participants who remained physically active compared to those who remained inactive (FVC odds ratio=0.31, 95% CI: 0.17, 0.55. FEV-1 odds ratio=0.43, 95% CI: 0.26, 0.72). Similar associations were observed in those who became active. This study suggests that remaining physically active or becoming active in older age is positively associated with lung function and reduced odds of abnormal lung function.

Trial baseline characteristics of a cluster randomised controlled trial of a school-located obesity prevention programme; the Healthy Lifestyles Programme (HeLP) trial

Background

We have developed a healthy lifestyles programme (HeLP) for primary school aged children (9–10 years), currently being evaluated in a definitive cluster randomised controlled trial. This paper descriptively presents the baseline characteristics of trial children (BMI, waist circumference, % body fat, diet and physical activity) by gender, cluster level socio-economic status, school size and time of recruitment into the trial.

Methods

Schools were recruited from across the South West of England and allocated 1:1 to either intervention (HeLP) or control (usual practice) stratified by the proportion of children eligible for free school meals (FSM, <19%, ≥19%) and school size (one Year 5 class, >1 Year 5 class). The primary outcome is change in body mass index standard deviation score (BMI sds) at 24 months post-randomisation. Secondary outcomes are BMI sds at 18 months, waist circumference and percentage body fat sds at 18 and 24 months, proportion of children classified as underweight, overweight and obese at 18 and 24 months, physical activity (for a sub-sample) and food intake at 18 months.

Results

At baseline 11.4% and 13.6% of children were categorised as overweight or obese respectively. A higher percentage of girls than boys (25.3% vs 24.8%) and children from schools in FSM category 2 (28.2% vs 23.2%) were overweight or obese. Children were consuming a mean (range) of 4.15 (0–13) energy dense snacks (EDS) and 3.23 (0–9) healthy snacks (HS) per day with children from schools in FSM category 2 consuming more EDS and negative food markers and less HS and positive food markers. Children spent an average 53.6 min per day (11.9 to 124.8) in MVPA and thirteen hours (779.3 min) per day (11 h to 15 h) doing less than ‘light’ intensity activity. Less than 5% of children achieved the Departments of Health’s recommendation of 60 min of MVPA every day.

Conclusion

We have excellent completeness of baseline data for all measures and have achieved compliance to accelerometry not seen before in other large scale studies. Our anthropometric baseline data is representative of local and national data for children this age and reflects the gender and socio-economic variations expected of children this age in relation to physical activity and weight status.

Trial registration

ISRCTN15811706 (1/05/2012).

Overweight and obesity in children and adolescents with Down syndrome-prevalence, determinants, consequences, and interventions: A literature review

BACKGROUND

Children with Down syndrome (DS) are more likely to be overweight or obese than the general population of youth without DS.

AIMS

To review the prevalence of overweight and obesity and their determinants in youth with DS. The health consequences and the effectiveness of interventions were also examined.

METHODS AND PROCEDURES

A search using MEDLINE, Embase, Web of Science, Scopus, CINAHL, PsycINFO, SPORTDiscus, LILACS, and COCHRANE was conducted. From a total of 4280 studies, we included 45 original research articles published between 1988 and 2015.

OUTCOMES AND RESULTS

The combined prevalence of overweight and obesity varied between studies from 23% to 70%. Youth with DS had higher rates of overweight and obesity than youths without DS. Likely determinants of obesity included increased leptin, decreased resting energy expenditure, comorbidities, unfavorable diet, and low physical activity levels. Obesity was positively associated with obstructive sleep apnea, dyslipidemia, hyperinsulinemia, and gait disorder. Interventions for obesity prevention and control were primarily based on exercise-based programs, and were insufficient to achieve weight or fat loss.

CONCLUSIONS AND IMPLICATIONS

Population-based research is needed to identify risk factors and support multi-factorial strategies for reducing overweight and obesity in children and adolescents with DS.

High Intensity Interval Training Improves Glycaemic Control and Pancreatic β Cell Function of Type 2 Diabetes Patients

Physical activity improves the regulation of glucose homeostasis in both type 2 diabetes (T2D) patients and healthy individuals, but the effect on pancreatic β cell function is unknown. We investigated glycaemic control, pancreatic function and total fat mass before and after 8 weeks of low volume high intensity interval training (HIIT) on cycle ergometer in T2D patients and matched healthy control individuals. Study design/method: Elderly (56 yrs±2), non-active T2D patients (n = 10) and matched (52 yrs±2) healthy controls (CON) (n = 13) exercised 3 times (10×60 sec. HIIT) a week over an 8 week period on a cycle ergometer. Participants underwent a 2-hour oral glucose tolerance test (OGTT). On a separate day, resting blood pressure measurement was conducted followed by an incremental maximal oxygen uptake (V˙O_2max) cycle ergometer test. Finally, a whole body dual X-ray absorptiometry (DXA) was performed. After 8 weeks of training, the same measurements were performed. Results: in the T2D-group, glycaemic control as determined by average fasting venous glucose concentration (p = 0.01), end point 2-hour OGTT (p = 0.04) and glycosylated haemoglobin (p = 0.04) were significantly reduced. Pancreatic homeostasis as determined by homeostatic model assessment of insulin resistance (HOMA-IR) and HOMA β cell function (HOMA-%β) were both significantly ameliorated (p = 0.03 and p = 0.03, respectively). Whole body insulin sensitivity as determined by the disposition index (DI) was significantly increased (p = 0.03). During OGTT, the glucose continuum was significantly reduced at -15 (p = 0.03), 30 (p = 0.03) and 120 min (p = 0.03) and at -10 (p = 0.003) and 0 min (p = 0.003) with an additional improvement (p = 0.03) of its 1^st phase (30 min) area under curve (AUC). Significant abdominal fat mass losses were seen in both groups (T2D: p = 0.004 and CON: p = 0.02) corresponding to a percentage change of -17.84%±5.02 and -9.66%±3.07, respectively. Conclusion: these results demonstrate that HIIT improves overall glycaemic control and pancreatic β cell function in T2D patients. Additionally, both groups experienced abdominal fat mass losses. These findings demonstrate that HIIT is a health beneficial exercise strategy in T2D patients.

Effectiveness of a school-based physical activity intervention on obesity in school children: a nonrandomized controlled trial

BACKGROUND

Childhood obesity has been a serious public health problem. An effective school-based physical activity (PA) intervention is still lacking in China. This study aimed to assess the effectiveness of a school-based physical activity intervention during 12 weeks on obesity and related health outcomes in school children.

METHODS

It was a non-randomized controlled trial. Altogether 921 children aged 7 to 15 years were recruited at baseline survey. Children in the intervention group (n = 388) participated in a multi-component physical activity intervention during 12 weeks that included improvement of physical education, extracurricular physical activities for overweight/obese students, physical activities at home, and health education lectures for students and parents. Children (n = 533) in the control group participated in usual practice.

RESULTS

Participants had mean age of 10.4 years, mean body mass index (BMI) of 19.59 kg/m2, and 36.8 % of them were overweight or obese at baseline survey. The change in BMI in intervention group (-0.02 ± 0.06 kg/m2) was significantly different from that in control group (0.41 ± 0.08 kg/m2). The adjusted mean difference was -0.43 kg/m2 (95% CI: -0.63 to -0.23 kg/m2, P < 0.001). The effects on triceps, subscapular, abdominal skinfold thickness and fasting glucose were also significant in intervention group compared with control group (all P < 0.05). The change in duration of moderate to vigorous physical activity (MVPA) in intervention group (8.9 ± 4.3 min/day) was significantly different from that in control group (-13.8 ± 3.3 min/day). The adjusted mean difference was 22.7 min/day (95% CI: 12.2 to 33.2 min/day, P < 0.001).

CONCLUSIONS

The school-based, multi-component physical activity intervention was effective to decreasing levels of BMI, skinfold thickness, fasting glucose and increasing duration of MVPA. These findings provided evidence for the development of effective and feasible school-based obesity interventions.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier: NCT02074332 (2014-02-26).

Physical activity and sedentary behaviors associated with risk of progression from gestational diabetes mellitus to type 2 diabetes mellitus: a prospective cohort study

IMPORTANCE

Women with a history of gestational diabetes mellitus (GDM) are at substantially increased risk of type 2 diabetes mellitus (T2DM). The identification of important modifiable factors could help prevent T2DM in this high-risk population.

OBJECTIVE

To examine the role of physical activity and television watching and other sedentary behaviors, and changes in these behaviors in the progression from GDM to T2DM.

DESIGN, SETTING, AND PARTICIPANTS

Prospective cohort study of 4554 women from the Nurses' Health Study II who had a history of GDM, as part of the ongoing Diabetes & Women's Health Study. These women were followed up from 1991 to 2007.

EXPOSURES

Physical activity and television watching and other sedentary behaviors were assessed in 1991, 1997, 2001, and 2005.

MAIN OUTCOMES AND MEASURE

Incident T2DM identified through self-report and confirmed by supplemental questionnaires.

RESULTS

We documented 635 incident T2DM cases during 59,287 person-years of follow-up. Each 5-metabolic equivalent hours per week (MET-h/wk) increment of total physical activity, which is equivalent to 100 minutes per week of moderate-intensity physical activity, was related to a 9% lower risk of T2DM (adjusted relative risk [RR], 0.91; 95% CI, 0.88-0.94); this inverse association remained significant after additional adjustment for body mass index (BMI). Moreover, an increase in physical activity was associated with a lower risk of developing T2DM. Compared with women who maintained their total physical activity levels, women who increased their total physical activity levels by 7.5 MET-h/wk or more (equivalent to 150 minutes per week of moderate-intensity physical activity) had a 47% lower risk of T2DM (RR, 0.53; 95% CI, 0.38-0.75); the association remained significant after additional adjustment for BMI. The multivariable adjusted RRs (95% CIs) for T2DM associated with television watching of 0 to 5, 6 to 10, 11 to 20, and 20 or more hours per week were 1 (reference), 1.28 (1.04-1.59), 1.41 (1.11-1.79), and 1.77 (1.28-2.45), respectively (P value for trend <.001); additional adjustment for BMI attenuated the association.

CONCLUSIONS AND RELEVANCE

Increasing physical activity may lower the risk of progression from GDM to T2DM. These findings suggest a hopeful message to women with a history of GDM, although they are at exceptionally high risk for T2DM, promoting an active lifestyle may lower the risk.

Active commuting to elementary school and adiposity: an observational study

BACKGROUND

Active commuting to school (ACS; walking or cycling to school) appears promising for decreasing children's obesity risk, although long-term studies are sparse. The aim was to examine whether kindergarten ACS was associated with fifth-grade adiposity.

METHODS

This study was a secondary analysis of the Early Childhood Longitudinal Study, Kindergarten (n=7938). Enrollment in kindergarten (1998-1999) was nationally representative of the United States and follow-up occurred in 2004. Kindergarten ACS was the main exposure variable and fifth-grade BMI z-score was the main outcome measure. Covariates included (1) neighborhood safety and BMI z-score in kindergarten and (2) demographics (i.e., age, gender, race/ethnicity, socioeconomic status, single- vs. two-parent households, region of country, and urbanicity in fifth grade). Three interactions were included: school travel*neighborhood safety; school travel*BMI z-score (kindergarten); and school travel*socioeconomic status. Analysis of covariance accounted for the complex sampling design.

RESULTS

Kindergarten ACS was associated with lower BMI z-score in fifth grade. The interaction of school travel*neighborhood safety indicated that children from less-safe neighborhoods who did ACS in kindergarten had a lower fifth-grade BMI z-score (p<0.05) than their peers who did not do ACS in kindergarten (i.e., in terms of BMI, this difference was -0.49 kg/m(2) for children of average height in less-safe neighborhoods).

CONCLUSION

Among children from less-safe neighborhoods, kindergarten ACS independently predicted lower BMI z-score in fifth grade among a national US cohort. Interventions and policies to increase ACS among young children, especially from unsafe neighborhoods, are warranted and should address parents' safety concerns.

Predictors of change in weight and waist circumference: 15-year longitudinal study in Australian adults

BACKGROUND/OBJECTIVES

This study examines which socio-demographic and lifestyle characteristics are associated with weight and waist circumference (WC) change in a cohort of Australian adults over a 15-year period (1992-2007). Further, it tests the effect of period of birth (birth cohort) on mean weight and WC at two time points, 15 years apart.

SUBJECTS/METHODS

Up to three repeated measures of weight (n=1437) and WC (n=1317) were used. Self-reported data on socio-demographic and lifestyle characteristics were derived from repeated questionnaires. Multivariable models, stratified by sex, were adjusted for potential confounders.

RESULTS

Participants born more recently were heavier, on average, than those in the same age group 15 years earlier, but there was no such secular trend in WC. Age at baseline was associated with change in weight and WC, but the pattern was different: participants gained weight up to age 55 years, while WC gain continued to 65 years. In women, higher level of recreational physical activity was associated with lower WC gain (P<0.05). Parity was also associated with WC change in women (P<0.05), but there was no linear trend.

CONCLUSIONS

Age was the most important factor associated with change in weight and WC in both sexes, apparently reducing the influence of all potential covariates. Among women, physical activity and parity were also associated with change in weight and WC. This study provides longitudinal evidence to support public health efforts that address the continuous increases in average weight and WC of many populations around the world.

Healthy Alberta Communities: impact of a three-year community-based obesity and chronic disease prevention intervention

OBJECTIVE

To assess the impact of a 3 year (2006-2009) community-based intervention for obesity and chronic disease prevention in four diverse "Healthy Alberta Communities" (HAC).

METHODS

Targeted intervention development incorporated the ANGELO conceptual framework to help community stakeholders identify environmental determinants of obesity amenable to intervention. Several inter-related initiatives were implemented. To evaluate, we surveyed separate samples of adults in HAC communities before and after the interventions and compared responses to identical survey questions asked of adults living in Alberta in two waves of the Canadian Community Health Survey (CCHS).

RESULTS

The HAC sample included 4761 (2006) and 4733 (2009) people. The comparison sample included 9775 and 9784 respondents in 2005 and 2009-10 respectively. Self-reported body mass index showed no change, and neither were there significant changes in behaviors relative to secular trends. Most significant outcomes were relevant to social conditions, specifically sense of belonging to community in the intervention communities.

CONCLUSION

Health outcome indicators at the community level may not be sufficiently sensitive to capture changes which, over a relatively short term, would only be expected to be incremental, given that interventions were directed primarily to creating environmental conditions supportive of changes in behavioral outcomes rather than toward health outcome change directly.

Associations Between Three School-Based Measures of Health

School-based body mass index (BMI) notification programs are often used to raise parental awareness of childhood overweight and obesity, but how BMI results are associated with physical fitness and diet is less clear. This study examined the relationship between BMI, fitness, and diet quality in a diverse sample of urban schoolchildren ( n = 122) utilizing a school-based cardiorespiratory fitness test and a food frequency questionnaire. Fifty-two percent of children were overweight/obese. Fit children were more likely to be normal weight than unfit children ( p < .001). Weight status was not associated with adherence to any specific dietary guidelines; however, greater overall adherence to the recommendations was associated with normal weight ( p < .05). These findings suggest a potential benefit may be gained by combining BMI reports with results of in-school fitness testing and basic information on how children’s diets compare to recommendations.

Energy balance and obesity: a UK perspective on the gluttonyv.sloth debate

Obesity in the UK was assumed to have developed against a population decline in physical activity, with health messages focused on diet and exercise prevention strategies. Doubly-labelled water (DLW) studies of energy expenditure have indicated the alternative scenario that the increased obesity prevalence reflects excessive food energy intake with physical activity levels unchanged. This analysis is questionable, deriving in part from a weakness of the DLW methodology in identifying changing physical activity levels within populations of increasing body weight. This has resulted in an underestimation of the reduction in physical activity in the overweight and obese, as revealed by direct studies of such behaviour. Furthermore, a close examination of food energy supply, household food purchases and individual food energy consumption since 1955, in relation to likely estimates of current intakes indicated by simple modelling of predicted energy expenditure, identifies: (a) food energy supply as markedly overestimating energy intakes; (b) individual food energy consumption as markedly underestimating energy intakes; and (c) household food purchase data as the closest match to predicted current food energy intakes. Energy intakes indicated by this latter method have fallen by between 20 to 30 %, suggesting comparable falls in physical activity. Although unequivocal evidence for a matching UK trend in falling physical activity is limited, as is evidence that obesity follows reductions in physical activity, such a link has been recently suggested in a large prospective study in adolescents. Thus, for the UK, obesity has developed within a ‘move less–eat somewhat less but still too much’ scenario. A focus on both diet and exercise should remain the appropriate public health policy.

The Healthy Lifestyles Programme (HeLP), a novel school-based intervention to prevent obesity in school children: study protocol for a randomised controlled trial

Background

Over the last three decades there has been a substantial increase in the proportion of children who are overweight or obese. The Healthy Lifestyles Programme (HeLP) is a novel school-based intervention, using highly interactive and creative delivery methods to prevent obesity in children.

Methods/Design

We describe a cluster randomised controlled trial to evaluate the effectiveness and cost effectiveness of HeLP. The intervention has been developed using intervention mapping (involving extensive stakeholder involvement) and has been guided by the Information, Motivation, Behavioural Skills model. HeLP includes creating a receptive environment, drama activities, goal setting and reinforcement activities and runs over three school terms. Piloting showed that 9 to 10 year olds were the most receptive and participative. This study aims to recruit 1,300 children from 32 schools (over half of which will have ≥19% of pupils eligible for free school meals) from the southwest of England. Participating schools will be randomised to intervention or control groups with baseline measures taken prior to randomisation. The primary outcome is change in body mass index standard deviation score (BMI SDS) at 24 months post baseline. Secondary outcomes include, waist circumference and percent body fat SDS and proportion of children classified as overweight or obese at 18 and 24 months and objectively measured physical activity and food intake at 18 months. Between-group comparisons will be made using random effects regression analysis taking into account the hierarchical nature of the study design. An economic evaluation will estimate the incremental cost-effectiveness of HeLP, compared to control, from the perspective of the National Health Service (NHS)/third party payer. An in-depth process evaluation will provide insight into how HeLP works, and whether there is any differential uptake or engagement with the programme.

Discussion

The results of the trial will provide evidence on the effectiveness and cost effectiveness of the Healthy Lifestyles Programme in affecting the weight status of children.

Trial registration

ISRCTN15811706

TV viewing and obesity among Norwegian children: the importance of parental education

AIM

To analyse the effect of lifestyle factors on the prevalence of overweight and obesity in 6-15-year-old Norwegian children.

METHODS

Questionnaire data on lifestyle factors (sedentary behaviour, activity and eating habits) and prevalence numbers of overweight and obesity based on measured height and weight were analysed using multinomial logistic regression in a sample of 2281 children included in the Bergen Growth Study.

RESULTS

More screen time increased the risk of overweight (odds ratio (OR): 1.25; p = 0.02) and obesity (OR: 1.12; p = 0.02) as did the presence of a TV in the child's bedroom (OR: 1.26 (overweight), OR: 1.81 (obese); p = 0.04). The obese children reported less sugar intake than the not overweight children (OR: 0.58; p = 0.01). Higher parental education was associated with less screen time (p = 0.02), lower frequency of TV in the child's bedroom (p = 0.001), more sports (p = 0.005), as well as eating more fruit and vegetables, less sweets, soft drinks and fast food, and more regular meals (for all, p < 0.03).

CONCLUSION

Indicators of sedentary lifestyle, such as screen time and the presence of a TV in the child's bedroom, were associated with overweight and obesity in Norwegian schoolchildren. Higher parental education was generally associated with less obesogenic lifestyle.

Correlates of adiposity among Latino preschool children

BACKGROUND

Childhood obesity is at record high levels in the US and disproportionately affects Latino children; however, studies examining Latino preschool children's obesity-related risk factors are sparse. This study determined correlates of Latino preschoolers' (ages 3-5 years) adiposity to inform future obesity interventions and policies.

METHODS

Latino preschoolers (n = 96) from 4 Head Start centers in Houston, Texas were recruited. Parents reported acculturation and neighborhood safety. Children's and parents' height and weight were measured. Children's television (TV) viewing was measured by TV diaries and physical activity by accelerometers. Linear regression was used with body mass index (BMI) z-score as the dependent variable and covariates sequentially added and retained in 4 blocks: 1) child age, gender, parent education, and BMI; 2) neighborhood safety and parent and child acculturation; 3) TV viewing; and 4) moderate-to-vigorous physical activity (MVPA).

RESULTS

In the final model (n = 96), only neighborhood disorder (β = 0.30, P = .005) and MVPA (β = -0.21, P = .049) were significantly associated with BMI z-score.

CONCLUSIONS

Among Latino preschoolers, higher neighborhood disorder and lower MVPA were associated with greater children's BMI z-scores.

A 12-week double-blind randomized clinical trial of vitamin D₃ supplementation on body fat mass in healthy overweight and obese women

BACKGROUND

Vitamin D concentrations are linked to body composition indices, particularly body fat mass. Relationships between hypovitaminosis D and obesity, described by both BMI and waist circumference, have been mentioned. We have investigated the effect of a 12-week vitamin D3 supplementation on anthropometric indices in healthy overweight and obese women.

METHODS

In a double-blind, randomized, placebo-controlled, parallel-group trial, seventy-seven participants (age 38 ± 8.1 years, BMI 29.8 ± 4.1 kg/m²) were randomly allocated into two groups: vitamin D (25 μg per day as cholecalciferol) and placebo (25 μg per day as lactose) for 12 weeks. Body weight, height, waist, hip, fat mass, 25(OH) D, iPTH, and dietary intakes were measured before and after the intervention.

RESULTS

Serum 25(OH)D significantly increased in the vitamin D group compared to the placebo group (38.2 ± 32.7 nmol/L vs. 4.6 ± 14.8 nmol/L; P<0.001) and serum iPTH concentrations were decreased by vitamin D3 supplementation (-0.26 ± 0.57 pmol/L vs. 0.27 ± 0.56 pmol/L; P<0.001). Supplementation with vitamin D3 caused a statistically significant decrease in body fat mass in the vitamin D group compared to the placebo group (-2.7 ± 2.1 kg vs. -0.47 ± 2.1 kg; P<0.001). However, body weight and waist circumference did not change significantly in both groups. A significant reverse correlation between changes in serum 25(OH) D concentrations and body fat mass was observed (r = -0.319, P = 0.005).

CONCLUSION

Among healthy overweight and obese women, increasing 25(OH) D concentrations by vitamin D3 supplementation led to body fat mass reduction.

Time use and physical activity: a shift away from movement across the globe

Technology linked with reduced physical activity (PA) in occupational work, home/domestic work, and travel and increased sedentary activities, especially television viewing, dominates the globe. Using detailed historical data on time allocation, occupational distributions, energy expenditures data by activity, and time-varying measures of metabolic equivalents of task (MET) for activities when available, we measure historical and current MET by four major PA domains (occupation, home production, travel and active leisure) and sedentary time among adults (>18 years). Trends by domain for the United States (1965-2009), the United Kingdom (1961-2005), Brazil (2002-2007), China (1991-2009) and India (2000-2005) are presented. We also project changes in energy expenditure by domain and sedentary time (excluding sleep and personal care) to 2020 and 2030 for each of these countries. The use of previously unexplored detailed time allocation and energy expenditures and other datasets represents a useful addition to our ability to document activity and inactivity globally, but highlights the need for concerted efforts to monitor PA in a consistent manner globally, increase global PA and decrease sedentary behavior. Given the potential impact on weight gain and other cardiometabolic health risks, the differential declines in MET of activity and increases in sedentary time across the globe represent a major threat to global health.

Physical activity and exercise in the regulation of human adipose tissue physiology

Physical activity and exercise are key components of energy expenditure and therefore of energy balance. Changes in energy balance alter fat mass. It is therefore reasonable to ask: What are the links between physical activity and adipose tissue function? There are many complexities. Physical activity is a multifaceted behavior of which exercise is just one component. Physical activity influences adipose tissue both acutely and in the longer term. A single bout of exercise stimulates adipose tissue blood flow and fat mobilization, resulting in delivery of fatty acids to skeletal muscles at a rate well-matched to metabolic requirements, except perhaps in vigorous intensity exercise. The stimuli include adrenergic and other circulating factors. There is a period following an exercise bout when fatty acids are directed away from adipose tissue to other tissues such as skeletal muscle, reducing dietary fat storage in adipose. With chronic exercise (training), there are changes in adipose tissue physiology, particularly an enhanced fat mobilization during acute exercise. It is difficult, however, to distinguish chronic "structural" changes from those associated with the last exercise bout. In addition, it is difficult to distinguish between the effects of training per se and negative energy balance. Epidemiological observations support the idea that physically active people have relatively low fat mass, and intervention studies tend to show that exercise training reduces fat mass. A much-discussed effect of exercise versus calorie restriction in preferentially reducing visceral fat is not borne out by meta-analyses. We conclude that, in addition to the regulation of fat mass, physical activity may contribute to metabolic health through beneficial dynamic changes within adipose tissue in response to each activity bout.

Evaluation of obesity clinic program in public community health centers in South Korea

The purpose of this study was to evaluate the obesity clinic program in the public community health centers in Korea in 2006-2007. The authors conducted a telephone questionnaire survey for participants to evaluate the outcome of the program. Samples were selected through convenient sampling: 30 persons per one public health center among 2560 participants. The level of improvement in obesity, regular exercise, and the effort for calorie reduction of the participants were analyzed. There were significant differences: The participants who were provided continuously the information of obesity clinic program reduced calories for weight loss (odds ratio [OR] = 2.37, 95% confidence interval [CI] = 1.34-4.19, P < .01), and showed concern about body weight (OR = 2.17, 95% CI = 1.07-4.41, P < 0.05). This study found that when the program information was provided continually and the participants were motivated, the community obesity program goals could be achieved.

Behavioural and weight status outcomes from an exploratory trial of the Healthy Lifestyles Programme (HeLP): a novel school-based obesity prevention programme

OBJECTIVES

To assess the behavioural and weight status outcomes in English children in a feasibility study of a novel primary school-based obesity prevention programme.

DESIGN

Exploratory cluster randomised controlled trial of the Healthy Lifestyles Programme.

SETTING

Four city primary schools (two control and two intervention) in the South West of England.

PARTICIPANTS

202 children aged 9-10 years, of whom 193 and 188 were followed up at 18 and 24 months, respectively. No child was excluded from the study; however, to be eligible, schools were required to have at least one single Year 5 class.

INTERVENTION

Four-phase multicomponent programme using a range of school-based activities including lessons, assemblies, parents' evenings, interactive drama workshops and goal setting to engage and support schools, children and their families in healthy lifestyle behaviours. It runs over the spring and summer term of Year 5 and the autumn term of Year 6.

PRIMARY AND SECONDARY OUTCOMES

Weight status outcomes were body mass index, waist circumference and body fat standard deviation scores (SDS) at 18 and 24 months, and behavioural outcomes were physical activity, television (TV) viewing/screen time and food intake at 18 months.

RESULTS

At 18 months of follow-up, intervention children consumed less energy-dense snacks and more healthy snacks; had less 'negative food markers', more 'positive food markers', lower mean TV/screen time and spent more time doing moderate-vigorous physical activity each day than those in the control schools. Intervention children had lower anthropometric measures at 18 and 24 months than control children, with larger differences at 24 months than at 18 months for nearly all measures.

CONCLUSIONS

Results from this exploratory trial show consistent positive changes in favour of the intervention across all targeted behaviours, which, in turn, appear to affect weight status and body shape. A definitive trial is now justified.

Longitudinal change in diet quality in Australian adults varies by demographic, socio-economic, and lifestyle characteristics

Knowledge of determinants of change in diet quality is needed, but it is relatively limited to date and mostly available from cross-sectional studies. We investigated longitudinal change in diet quality and its associations with period of birth (birth cohort) and socio-demographic and lifestyle characteristics. We used dietary intake data collected by FFQ in 1992, 1996, and 2007 from a population-based random sample of adults comprising 1511 men and women aged 25-75 y at baseline and applied generalized estimating equations to examine determinants of long-term change in diet quality, calculated using a diet quality index reflecting dietary guidelines for Australian adults. Information on socio-demographic and lifestyle factors was derived from self-reported questionnaires. Multivariable models, stratified by sex, were adjusted for confounders. We showed that there was an overall increase in diet quality in both men and women, but scores related to intake of fruit (men only), cereals, and food variety decreased during a 15-y follow-up. Younger age, higher occupational level (men only), and low to medium level of physical activity and hormone replacement therapy use in women were independently associated with greater improvement in diet quality over time (P < 0.05). In conclusion, despite an overall improvement in diet quality over time, this study suggests that efforts to further improve diet quality in Australia should focus on increasing consumption of fruit, cereals, and a greater variety of foods. More evidence from studies that assess change in dietary quality in longitudinal studies is needed to corroborate these findings.

Diet quality and change in anthropometric measures: 15-year longitudinal study in Australian adults

Evidence from longitudinal studies on the association between diet quality and change in anthropometric measures is scarce. We therefore investigated the relationship between a recently developed food-based dietary index and change in measured BMI and waist circumference (WC) in Australian adults (1992–2007). We used data from the Australian population-based Nambour Skin Cancer Study comprising 1231 adults aged 25–75 years at baseline (1992). We applied generalised estimating equations (GEE) to examine the association between diet quality and change in anthropometric measures. Dietary intake was assessed by an FFQ in 1992, 1996 and 2007. Diet quality was estimated using the dietary guideline index (DGI), developed to reflect the dietary guidelines for Australian adults; a higher score indicating increased compliance. Multivariable models, stratified by sex, were adjusted for sociodemographic and lifestyle characteristics. We show that men with higher diet quality had a lower gain in BMI as compared to those with low diet quality during the 15-year follow-up. In a multivariable adjusted model, as compared to men in quartile 1 (reference), those in the highest quartile had the lowest gain in BMI (mean (95 % CI): 0·05 (0·00, 0·09) v. 0·11 (0·06, 0·16) kg/m2 per year, P =0·01). Diet quality was inversely, but non-significantly associated with change in WC. In women, DGI score was unrelated to change in any body measure. Energy underreporting did not explain the lack of association. We conclude that adherence to a high-quality diet according to Australian dietary guidelines leads to lower gain in BMI and WC in middle-aged men, but not in women.

Active commuting to school and association with physical activity and adiposity among US youth

BACKGROUND

Walking or bicycling to school (ie, active commuting) has shown promise for improving physical activity and preventing obesity in youth. Our objectives were to examine, among US youth, whether active commuting was inversely associated with adiposity and positively associated with moderate-to-vigorous physical activity (MVPA). We also examined whether MVPA mediated the relationships between active commuting and adiposity.

METHODS

Using data of participants aged 12 to 19 years from the US National Health and Nutrition Examination Survey 2003 to 2004 (n=789 unweighted), we constructed multiple linear regression models that controlled for dietary energy intake and sociodemographics. The main exposure variable was active commuting. The outcomes were BMI z-score, waist circumference, skinfolds and objectively measured MVPA. The product-of-coefficients method was used to test for mediation.

RESULTS

Active commuting was inversely associated with BMI z-score (β=-0.07, P=.046) and skinfolds (β=-0.06, P=.029), and positively associated with overall daily (β=0.12, P=.024) and before- and after-school (β=0.20, P<.001) MVPA. Greater before- and after-school MVPA explained part of the relationship between active commuting and waist circumference (Sobel z=-1.98, P=.048).

CONCLUSIONS

Active commuting was associated with greater MVPA and lower measures of adiposity among US youth. Before- and after-school MVPA mediated the relationships between active commuting and waist circumference.

Distribution of physical activity facilities in Scotland by small area measures of deprivation and urbanicity

BACKGROUND

The aim of this study was to examine the distribution of physical activity facilities by area-level deprivation in Scotland, adjusting for differences in urbanicity, and exploring differences between and within the four largest Scottish cities.

METHODS

We obtained a list of all recreational physical activity facilities in Scotland. These were mapped and assigned to datazones. Poisson and negative binomial regression models were used to investigate associations between the number of physical activity facilities relative to population size and quintile of area-level deprivation.

RESULTS

The results showed that prior to adjustment for urbanicity, the density of all facilities lessened with increasing deprivation from quintiles 2 to 5. After adjustment for urbanicity and local authority, the effect of deprivation remained significant but the pattern altered, with datazones in quintile 3 having the highest estimated mean density of facilities. Within-city associations were identified between the number of physical activity facilities and area-level deprivation in Aberdeen and Dundee, but not in Edinburgh or Glasgow.

CONCLUSIONS

In conclusion, area-level deprivation appears to have a significant association with the density of physical activity facilities and although overall no clear pattern was observed, affluent areas had fewer publicly owned facilities than more deprived areas but a greater number of privately owned facilities.

The influence of a high intensity physical activity intervention on a selection of health related outcomes: an ecological approach

Background

Cardiovascular disease (CVD) is the main cause of mortality throughout the world. With accumulating evidence suggesting that CVD has its origins in childhood, it is unsurprising that research into obesity prevalence within school aged youth is burgeoning.

Within this study our primary objective will be to examine whether high intensity interval training (HIT) improves the CVD risk profile of secondary school aged adolescents. Our secondary objective will be to identify the prevalence of CVD risk factors and examine factors associated with these in adolescents aged 15 - 18 years.

Method/Design

A South Lanarkshire school of low socioeconomic status (SES) was selected to participate in the study intervention. Participants from secondary 5 (15 - 17 years) and 6 (16 - 18 years) will be recruited for this study. Participants from secondary 6 will be randomly assigned to Group A (HIT) or Group B (moderate-vigorous) and will perform each protocol three times weekly. The secondary 5 participants will act as the control group. Data collection will take place during the Physical Education (PE) lessons and on school premises and will include: anthropometrical variables (height, weight, waist and hip circumferences, skinfold thickness at two sites), physiological responses (blood pressure, aerobic fitness, heart rate (HR) response, vertical jump performance, 10-metre (m) sprint, 50-m sprint and 505-agility test), diet (self-reported seven-day food diary), physical activity (Physical Activity Questionnaire for Adolescents (PAQ-A)) and blood tests (fasting glucose, insulin, total cholesterol (TC), high-density lipoprotein (HDL), high-sensitivity C-reactive protein (hs-CRP), fibrinogen (Fg), interleukin-6 (IL-6), adiponectin (high molecular weight), triglyceride and plasminogen activator inhibitor-1 (PAI-1). An environmental audit of the secondary school and the health related quality of life (HRQOL) of the participants will also be measured. Finally, all exercise sessions will be video recorded and rate of perceived exertion (RPE) and mood states will also be taken after each exercise session.

Discussion

Our study may be able to demonstrate a time efficient means of reducing CVD risk factors in adolescents.

Trial Registration

NCT01027156

Prospective associations between objective measures of physical activity and fat mass in 12-14 year old children: the Avon Longitudinal Study of Parents and Children (ALSPAC)

OBJECTIVE

To investigate associations between physical activity at age 12 and subsequent adiposity at age 14.

DESIGN

Prospective birth cohort study with data collected between 2003 and 2007.

SETTING

Original recruitment in 1991-2 of 14,541 pregnant women living in the former County of Avon (United Kingdom).

PARTICIPANTS

At age 12, 11,952 children were invited to attend the research clinic. Of these, 7159 attended, and 4150 (1964 boys, 2186 girls) provided sufficient data on exposure, outcome, and confounding variables.

MAIN OUTCOME MEASURE

Fat mass at age 14, measured by dual emission x ray absorptiometry, associated with physical activity at age 12, measured by accelerometry.

RESULTS

Prospective associations of fat mass at age 14 (outcome) with physical activity at age 12 (exposure) were strong for both total activity (accelerometer counts/min) and for daily amount of moderate-vigorous physical activity (min/day). An extra 15 minutes of moderate-vigorous physical activity per day at age 12 was associated with lower fat mass at age 14 in boys (by 11.9% (95% confidence interval 9.5% to 14.3%)) and girls (by 9.8% (6.7% to 12.8%)). The proportion of physical activity due to moderate-vigorous physical activity was between 20% and 30% in boys and girls at the two ages.

CONCLUSIONS

Higher levels of physical activity, in particular activity of moderate to higher intensities, are prospectively associated with lower levels of fat mass in early adolescence. Interventions to raise levels of physical activity in children are likely to be important in the fight against obesity.

Asian Indians of Guadeloupe are less physically active than their island counterparts

The status of ethnic minority has been reported to be associated with a tendency toward sedentary behavior. The Guadeloupean population is composed of Afro-Caribbeans and an Asian Indian minority. This study examined the association of ethnicity and physical activity on the island. Energy expenditures (EE), energy intakes (EI), and macronutrient intakes of 122 Guadeloupean workers (60 Indians and 62 controls) were assessed by three consecutive 24-h recalls. Two-way analyses of variance were conducted to test the hypothesis of an effect of ethnicity, taking the potential effect of sex into account, on these variables. Asian Indians reported lower EE (P=0.011), lower EE/EI ratios (P=0.001), and lower physical activity (P=0.003) than their Afro-Carribean counterparts. Their food intakes were not different in terms of EI or macronutrient intake. No sex x ethnicity interactions were significant. The present study reports a tendency toward physical inactivity in Asian Indians of Guadeloupe associated with EI similar to those of controls. Sedentary lifestyles and energetic imbalances are well-documented risk factors for several diseases, including type 2 diabetes and cardiovascular disease, both major public health concerns in Guadeloupe. Strategies to prevent sedentary lifestyles should be considered for Asian Indian Guadeloupeans.