Physical activity growth curves relate to adiposity in adolescents

PurposeFindings from prospective studies on associations between physical activity and adiposity among youth are inconsistent. Our aim was to describe physical activity trajectories during secondary school and examine the association with change in adiposity in youth.MethodsPhysical activity was measured in 20 survey cycles from 1999 to 2005; anthropometrics were measured in survey cycles 1, 12, and 19. Individual growth curves modeling moderate-to-vigorous physical activity (MVPA) and vigorous physical activity (VPA) were estimated. Estimates of initial level and rate of decline in MVPA and VPA bouts per week were included as potential predictors of body fat% and body mass index using age- and sex-specific linear regression.ResultsComplete data were available for 840 and 760 adolescents aged 12–13 years at baseline, followed from survey cycles 1–12 and 12–19, respectively. Among girls, yearly declines of one MVPA and one VPA bout per week during earlier adolescence were associated with increases of 0.19 (95% confidence interval [CI], 0.02–0.36) and 0.47 (95% CI, 0.015–0.92) units of body fat%, respectively. In boys, a yearly decline of one MVPA bout per week was associated with an increase of 0.38 (95% CI, 0.05–0.70) units of body fat% during later adolescence.ConclusionsObesity prevention programs should include strategies to prevent declines in physical activity.     

Food Availability en Route to School and Anthropometric Change in Urban Children

This study examined food availability along children’s paths to and from elementary school, and associations with change in body mass index (BMI) and waist circumference over 1 year. Secondary data from 319 children aged 8–13 years from the “Multiple Opportunities to Reach Excellence” Project was used. Child anthropometry and demographic variables were obtained at baseline (2007) and 1 year follow-up. Food outlet locations (n = 1,410) were obtained from the Baltimore City Health Department and validated by ground-truthing. Secondary data on healthy food availability within select food stores in Baltimore City in 2007 were obtained via a validated food environment assessment measure, the Nutrition Environments Measures Study. Multilevel models were used to examine associations between availability of healthy food and number of various food outlets along paths to school and child anthropometric change over 1 year. Controlling for individual-, neighborhood-, and school-level characteristics, results indicated that higher healthy food availability within a 100 m buffer of paths to school was associated with 0.15 kg/m² lower BMI gain (p = 0.015) and 0.47 cm smaller waist circumference gain (p = 0.037) over 1 year. Although prior research has illuminated the importance of healthy food choices within school and home environments, the current study suggests that exposure to the food environment along paths to school should be further explored in relation to child health outcomes.

Electronic supplementary material

The online version of this article (doi:10.1007/s11524-012-9785-4) contains supplementary material, which is available to authorised users.     

Cardiac response to progressive cycle exercise in moderately obese adolescent females

PURPOSE: To assess cardiac responses to exercise and cardiac functional capacity in moderately obese adolescent females. METHODS: Thirteen healthy females (mean age 13.6 +/- 1.5 years) with a body mass index from 30 to 43 kg per m(2) underwent maximal cycle testing. Cardiac responses were measured by Doppler echocardiogram, and gas exchange variables were determined with open circuit spirometry. Data were analyzed by independent Student's t-tests. RESULTS: Peak oxygen uptake relative to height(3.0) was significantly greater in the obese (570 +/- 90 ml m(-3)) compared to the nonobese controls (485 +/- 60 ml m(-3)). This difference was explained by a higher peak cardiac output (4.50 +/- 1.06 L m(-3) vs. 3.81 +/- 58 L m(-3)) and stroke volume (24 +/- 5 ml m(-3) vs. 19 +/- 3 ml m(-3)) in the obese. Maximal cardiac index was similar in the two groups. There was no evidence of myocardial dysfunction during exercise in either group. CONCLUSIONS: Low aerobic fitness in obese adolescents as indicated by depressed peak VO(2) per kg body mass and limited endurance performance does not reflect decreased cardiac functional capacity.     

Number of aberrant crypt foci associated with adiposity and IGF1 bioavailability

Background  Dysregulation of the insulin-like growth factor (IGF) system, a common consequence of adiposity-induced insulin resistance, may be a key underlying mechanism linking excess body weight with colon cancer. Evidence has been derived from studies of cancer and polyps. Supporting data about aberrant crypt foci (ACF), putative pre-polyp changes, have been generated only from animal studies to date. Methods  We randomly selected 26 patients with sex-specific elevated waist-hip-ratio (WHR) and 26 with normal values from a series of 150 patients seeking routine colonoscopy at the University of Connecticut Health Center. Cross-sectional analyses were performed of ACF number (<5, ≥5) in relation to total IGF1, IGF-binding protein-3 (IGFBP3), insulin, body mass index (BMI), WHR and waist circumference (WC). Visualized ACF in the 20 cm of the distal colon were counted using advanced endoscopic imaging. Results  Patients with ≥5 ACF had higher BMI, WHR, and WC compared with patients with >5 ACF (p = 0.04, p = 0.03, and p = 0.01, respectively). IGFBP3 was reduced (p = 0.02) and IGF1:IGFBP3 molar ratio was greater (p = 0.03) in patients with ≥5 ACF. We did not observe significant associations between ACF number and insulin or total IGF1. Conclusions  Our study provides the first report in humans of a possible association of ACF prevalence and IGF1 bioavailability as characterized by IGF1:IGFBP3 molar ratio and IGFBP3 level. More research is needed to determine whether this relationship is varied by ACF features (e.g., size, dysplasia, molecular changes), synchronous cancer and polyps, and is modified by colon cancer risk factors.     

Body composition measured by dual-energy X-ray absorptiometry half-body scans in obese children

Aim: To perform a methods comparison of a left or right half‐body scan versus whole‐body scan for measuring body composition in a sample of obese children. Methods: A group of obese children (n = 58; ≥95th BMI percentile; 8–18 years) were required to undergo a dual‐energy X‐ray absorptiometry (DXA) body composition measurement as part of an ongoing cohort study; 34 fit within the imaging field of the DXA scanner and were eligible for inclusion in the present analysis. Percent fat, total mass, fat mass, lean mass and bone mineral content (BMC) were estimated from half‐body scans and compared with the whole‐body results. Assessment was completed using GE enCORE 11.40 software. Results: In comparing left‐ and right‐side scans to whole‐body scans, there was significant correlation for all body composition variables (p ≤ 0.005, R² = 0.996–1.0). Bland Altman analyses also showed high levels of agreement between half‐body estimates and whole‐body measurements. Conclusion: This study supports using a half‐body scan methodology for percent fat, total mass, fat mass, lean mass, and BMC as a valid alternative to full‐body analysis in obese children and youth.     

Effects of body composition profiles on oncological outcomes and postoperative intraabdominal infection following colorectal cancer surgery

BackgroundAnthropometric data as prognostic factors of colorectal cancer are promising but contradictory. The aim of this study was to assess the preoperative body composition profiles as predictive factors for postoperative, oncologic, and inflammation outcomes.ObjectivesWe sought to assess the impact of body composition profiles on short- and long-term outcomes and on postoperative inflammatory response in a clinical setting for patients following curative intent surgery for colorectal cancer.SettingUniversity hopsitalMethodsWe analyzed 122 patients from a prospective cohort (IMACORS) with colorectal cancer undergoing curative-intent surgery from 2011 to 2014. Musculature, total, visceral, and subcutaneous adiposity were measured from a preoperative CT scan and outcomes were compared between profiles.ResultsPreoperative myopenia was an independent predictive factor of recurrence (HR = 3.3 95% CI = 1.6–6.9; P = .002) while subcutaneous adiposity was a protective factor (HR = .4 95% CI = .2–.9; P = .03). No anthropometric measurement was predictive of overall survival and postoperative intra abdominal infection was not determined by body composition profiles. Preoperative and D4 CRP levels were significantly higher in patients with subcutaneous adiposity.ConclusionsMyopenia and subcutaneous adiposity seemed to have independent and opposite prognostic effects on recurrence. Muscle mass loss may represent a modifiable risk factor while the amount of subcutaneous adipose tissue reflects an energetic storage favorable to face this pathologic process.     

Prevalence of adiposity and its association with sleep duration,quality, and timing among 9–12-year-old children in Guangzhou,China

Background

Short sleep duration has been reported to be associated with obesity in children, but findings are not consistent. Since few studies have examined the relationship between more complex sleep characteristics and obesity, we examined the association between adiposity and self-reported sleep duration, bedtime, and sleep quality in 9–12-year-old Chinese children using multilevel mixed models.