Search

This study examined the effect of ponderal index (PI) at birth on the relationships between eight common polymorphisms of the leptin (LEP) and leptin receptor (LEPR) genes and adiposity in adolescents. A total of 823 European adolescents (45.4% girls) aged 14.8 ± 1.4 years were genotyped for the LEP (rs2167270, rs12706832, rs10244329, rs2071045, and rs3828942) and LEPR (rs1137100, rs1137101, and rs8179183) polymorphisms. The PI was calculated from parental reports of birth weight and length. Fat mass index (FMI) was calculated. Analyses were adjusted for relevant confounders. An "adiposity-risk-allele score" based on genotypes at the three single-nucleotide polymorphisms (SNPs) associated with adolescents' FMI in adolescents within the lower tertile of PI was calculated. The LEP rs10244329 and rs3828942 polymorphisms were associated with higher FMI only in adolescents within the lower PI tertile (+0.55 kg/m(2) per minor T allele, P = 0.040, and +0.58 kg/m(2) per major G allele, P = 0.028, respectively). The LEPR rs8179183 polymorphism was significantly associated with higher FMI in adolescents within the lower PI tertile (+0.87 kg/m(2) per minor C allele, P = 0.006). After correction for multiple comparisons, only the association between the LEPR rs8179183 and FMI persisted. However, each additional risk allele conferred 0.53 kg/m(2) greater FMI in adolescents within the lower tertile of PI (P = 0.008). In conclusion, our results suggest that those adolescents born with lower PI could be more vulnerable to the influence of the LEP rs10244329 and rs3828942 polymorphisms and LEPR rs8179183 polymorphism on total adiposity content. Due to the relatively small sample size, these findings should be replicated in further larger population samples.

Background: The aim of this study was to evaluate the occurrence and severity of mechanical ventilatory constraints in healthy prepubescent children during continuous and intermittent exercise., Methods: Twelve prepubescent children (7-11 years old) performed 7 exercises on a treadmill: one graded test for the determination of maximal aerobic speed (MAS), three continuous exercises (CE) at 60, 70, and 80% of MAS and three intermittent exercises (IE), alternating 15 sec of exercise with 15 sec of passive recovery, at 90, 100, and 110% of MAS. During each CE and IE, tidal flow/volume loops were plotted within a maximal flow/volume loop (MFVL) measured at rest before each exercise. Expiratory flow limitation (expFL expressed in %Vt) was defined as the part of exercise tidal volume (Vt) meeting the boundary of MFVL. Breathing strategy was estimated by measuring inspiratory capacity relative to forced vital capacity and tidal volume relative to inspiratory capacity. Other breathing pattern parameters (ventilation VE, Vt, respiratory frequency f) were continuously recorded during exercise., Results: An "intensity" effect was found for VE during CE (P < 0.001) but not during IE (P = 0.08). The increase in VE was predominantly assumed by an increase in f for both exercise modalities. During each exercise, several children heterogeneously experienced expFL ranging between 10 and 90%Vt. For all exercises, Vt was predominantly regulated by an increase in Vt/IC with no change in IC/FVC from rest to exercise. Finally, no significant "modality" effect was found for mechanical ventilatory constraint parameters (expFL, Vt/IC, and IC/FVC)., Discussion: We could conclude that neither of the modalities studied induced more mechanical ventilatory constraints than the other, but that exercise intensities specific to each modality might be greater sources of exacerbation for mechanical ventilatory constraints., (Copyright © 2011 Wiley-Liss, Inc.)

The authors' aim in this cross-sectional study was to characterize levels of objectively measured physical activity and sedentary time in adolescents from 9 European countries. The study comprised 2,200 European adolescents (1,184 girls) participating in the HELENA cross-sectional study (2006-2008). Physical activity was measured by accelerometry and was expressed as average intensity (counts/minute) and amount of time (minutes/day) spent engaging in moderate- to vigorous-intensity physical activity (MVPA). Time spent in sedentary behaviors was also objectively measured. Cardiorespiratory fitness was measured by means of the 20-m shuttle run test. Level of maternal education was reported by the adolescents. A higher proportion of boys (56.8% of boys vs. 27.5% of girls) met the physical activity recommendations of at least 60 minutes/day of MVPA. Adolescents spent most of the registered time in sedentary behaviors (9 hours/day, or 71% of the registered time). Both average intensity and MVPA were higher in adolescents with high cardiorespiratory fitness, and sedentary time was lower in the high-fitness group. There were no physical activity or sedentary time differences between maternal education categories. These data provide an objective measure of physical activity and amount of time spent in sedentary behaviors in a relatively large number of European adolescents.

Objective: Genetic variability in the NR1H3 gene (encoding LXRα) and in several of its target genes is associated with serum HDL-cholesterol (HDL-C) concentrations. We sought to assess if these associations could be detected in adolescents., Methods: Thirty-nine polymorphisms in NR1H3, ABCA1, APOE, CETP, PLTP and LPL were analysed in the HELENA study (n = 1144 European adolescents)., Results: The minor alleles of rs11039155 in NR1H3, rs2575879 in ABCA1, rs708272, rs17231506 and rs5882 in CETP and rs328 in LPL were associated with higher serum HDL-C concentrations (p ≤ 0.0012). The minor alleles of rs12221497 in NR1H3, rs1800978 in ABCA1 and the APOE ɛ4 allele were associated with lower HDL-C concentrations (p ≤ 0.01). The combined set of associated polymorphisms accounted for ∼6.6% of the variance in HDL-C., Conclusion: We report for the first time that polymorphisms in NR1H3 and its target genes ABCA1, APOE, CETP and LPL contribute to the genetic variance for HDL-C concentrations in adolescence., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

The objective of the present study was to evaluate the effect of a paediatric tube feed supplemented with a multifibre mixture on the gut microbiota and nutritional and micronutrient status of children on long-term enteral nutrition (EN). A randomised, controlled, double-blind, cross-over trial (2 × 3 months) with a washout period of 1 month was carried out. Twenty-seven children (80% neurologically impaired) aged 11.9 (SD 3.9) years, on long-term EN (4.8 (SD 3.9) years) were recruited. The analyses of the children's faecal pH, microbiota along with anthropometric measures, bowel movements and markers of blood micronutrient status were made. Twenty children completed the study. A significant increase in the proportion of stool bifidobacteria (+16.6%, P < 0.05) was observed during the multifibre period than during the fibre-free period, together with a significant reduction in stool pH (P < 0.001). Stool frequency and consistency as well as growth did not differ between the two periods. There was a significant increase (P < 0.05) in plasma ferritin at the end of the fibre-free period, but plasma ferritin levels remained within normal ranges during both periods. No diet effects on other blood parameters were observed. In conclusion, addition of a multifibre mixture with prebiotic components to paediatric EN is well tolerated, promotes bifidobacteria and reduces stool pH, indicating an improved gut health.

The aim of this article is to determine correspondences between three levels of continuous and intermittent exercise (CE and IE, respectively) in terms of steady-state oxygen uptake (VO(2SS)) and heart rate (HR) in children. Fourteen healthy children performed seven exercises on a treadmill: one graded test for the determination of maximal aerobic speed (MAS), three CE at 60, 70 and 80% of MAS (CE60, CE70 and CE80) and three IE (alternating 15 s of exercise intercepted with 15 s of passive recovery) at 90, 100 and 110% of MAS (IE90, IE100 and IE110). Mean VO(2SS) and mean HR were determined for both continuous and intermittent exercises. For comparison, three associations were designed: CE60 versus IE90, CE70 versus IE100 and CE80 versus IE110. No VO(2SS) difference was observed for CE60 versus IE90 and CE70 versus IE100 whereas a significant difference (P < 0.01) was found for CE80 versus IE110 (1.36 +/- 0.45 vs. 1.19 +/- 0.38 L min(-1), respectively). Significant linear regressions were found for the three CE versus IE associations for VO(2SS) (0.60 < r (2) < 0.99, P < 0.05). For the three associations, mean HR presented no significant difference. Only one significant relation was found for CE80 versus IE110 association (r(2) = 0.49, P < 0.05). Correspondences between CE and IE intensities are possible in terms of VO(2SS) whatever the level of exercise; even if for high intensities, VO(2SS) was higher during CE. These results demonstrated that it is possible to diversify the exercise modality while conserving exercise individualization.

Context: Plasma-borne angiopoietin-like proteins (ANGPTL) act as endocrine factors on their target tissues. Because ANGPTL3 and ANGPTL4 play important roles in lipid metabolism and the regulation of adiposity in mice, we hypothesized that genetic variability at the ANGPTL3 and ANGPTL4 genes loci might influence lipid metabolism and fat deposition in humans., Objective: The aim of the study was to examine the association between ANGPTL3 and ANGPTL4 genetic polymorphisms and metabolic phenotypes in adolescent and adult samples., Design and Participants: Two independent population-based studies, one composed of 1144 adolescents (mean age, 14.8 +/- 1.4 yr) from nine European countries (the HELENA study) and the other composed of 1155 adults (age range, 35-65 yr) from Northern France (the MONICA Lille study), were genotyped for one ANGPTL3 polymorphism and four ANGPTL4 polymorphisms., Results: The ANGPTL3 rs11207997 polymorphism (minor allele frequency, 0.32) was associated with lower plasma HDL-cholesterol and apolipoprotein A-I levels in both adolescents (P = 0.0004, P = 0.00006, respectively) and adults (P = 0.03, P = 0.02, respectively). The ANGPTL4 rs4076317 polymorphism (minor allele frequency, 0.29) was associated with a higher percentage of body fat (P = 0.02) in adolescents and a higher waist-to-hip ratio (in interaction with the peroxisome proliferator-activated receptor gamma Pro12Ala polymorphism) in adults (P = 0.0004)., Conclusion: The present study underlines the role of ANGPTL3 in HDL-cholesterol metabolism as early as in adolescence. Our data also suggest possible associations between ANGPTL4 polymorphisms and body fat, but these findings require replication.

The aim of this study was to compare equivalence and agreement of physical activity output data collected by a Research Tri-axial accelerometer (R3T) during walking and running on a treadmill versus on land. Fifty healthy volunteers, 35 males (age 21.9 +/- 1.8 years) and 15 females (age 21.6 +/- 0.7 years), underwent a series of tests on a treadmill and on land with the order of testing administered randomly. Each participant walked for 10 min at 4 km x h(-1) and 6 km x h(-1), and ran at 8 km x h(-1) and 10 km x h(-1), with the same accelerometer. Analysis of output data was assessed by two statistical tests: the equivalence test and Bland and Altman method. Mean differences for walking were 41.2 +/- 129.8 counts per minute and -68.8 +/- 173.15 counts per minute at 4 km . h(-1) and km x h(-1), respectively. Mean differences for running were 19.1 +/- 253.20 counts per minute and 38.9 +/- 270.2 counts per minute at 8 km x h(-1) and 10 km x h(-1), respectively. The physical activity output data from the treadmill were higher by an average of 3.5% than the data collected on land. The differences obtained between the treadmill and on land were small and non-significant. The equivalence test showed that output data from the treadmill versus on land were equivalent (P < 0.05). The Bland and Altman method showed good agreement between the counts obtained on the treadmill and on land (P < 0.05). In conclusion, physical activity output data were similar as measured by the RT3 accelerometer on a treadmill and on land. The findings suggest that the RT3 may be used in a laboratory and extrapolated to data obtained on land.

Introduction: Exercise testing is useful in the respiratory evaluation of patients with cystic fibrosis. The shuttle walk test (SWT) is a progressive, externally paced, exercise test requiring the subject to walk/run back and forth between two fixed points. The aim is to assess the reproductibility of the SWT in paediatric patients with cystic fibrosis., Methods: This prospective study recruited 31 children with stable disease. The patients performed two SWT one day (SWT 1 and 2) and two others (SWT 3 and 4) within 15 days. Only SWT 2 and 4 were assessed for reproducibility., Results: 61% were boys, median age (range): 12.9 (7-18.9) years, median Shwachman score (range): 80 (65-100), median values for FEV1 and FVC (range): 92 (55-154) and 92 (64-140)% predicted, respectively. Median distance for SWT 2-4 (range): 910 (580-1020) and 925 (540-1020) metres. Reproducibility for SWT distance and physical activity measured by an accelerometer is very good (intra-class correlation coefficient=0.90 and 0.92, respectively). SWT distance correlated with physical activity (p=3.10(-4)) and weight (p=0.03). SWT distance was independent of the following parameters: height, weight-for-age Z-score, FEV1, FVC, Shwachman score, colonisation with Pseudomonas aeruginosa., Conclusions: The SWT is reproducible in paediatric patients with cystic fibrosis and provides assessment of respiratory performance that complements spirometric measures of lung function.