Cardiorespiratory fitness has declined among French children since 1999, although the decline appears to be getting smaller

BACKGROUND

Cardiorespiratory fitness (CRF) is a strong marker of current and future health. The aim of this study was to assess the national temporal trends in CRF for French children and adolescents between 1999 and 2022.

METHODS

CRF data were obtained from several cross-sectional studies on 15 420 (51.1% boys) French children and adolescents aged 9-16 years between 1999 and 2022. The 20-m shuttle run test (20mSRT) estimated CRF. Body mass index (BMI) was calculated from measured height and body mass, with BMI z-scores (BMIz) calculated using WHO growth curves. The 20mSRT results were corrected for protocol and converted to z-scores (20mSRTz) using international sex- and age-specific norms. With additional adjustment for BMIz, temporal trends in mean 20mSRT performance (20mSRTz) were estimated using linear regression, with the distance max (Dmax) method used to locate a breakpoint and linear segments fitted to points below and above the breakpoint. Trends in distributional characteristics were assessed visually and described as the ratio of the coefficients of variation (CVs).

RESULTS

After adjustment for protocol, age, sex, and BMIz, a large decline in mean 20mSRT performance (trend per decade (95% CI): -1.42 SDs (-1.45, -1.39) or -18.4% (95% CI: -18.8, -18.0)) between 1999 and 2022 was found. Dmax located a breakpoint for the two-linear-segment model in year 2010. There was a large decline in mean 20mSRT performance pre-2010 (trend per decade (95% CI): -2.31 SDs (-2.39, -2.24)), which reduced 0.06-fold to a negligible decline post-2010 (trend per decade (95% CI): -0.15 SD (-0.20, -0.10)). We also found that the trend in mean 20mSRT performance was not uniform across the population distribution. Between 1999 and 2022, there was a small trend in distributional asymmetry, with slightly smaller declines experienced by the high performers (above the 75th percentile).

CONCLUSIONS

Our data suggest a large decline in the 20mSRT performance of French children and adolescents since 1999. This declining trend seems to have diminished considerably since 2010. Such declines in CRF could translate into declines in health status. Although a slowing in the declining trend in CRF in recent years is encouraging, more data are needed to confirm these findings.

The International Fitness Scale (IFIS): A valid tool to assess physical fitness in French children

BACKGROUND

The need for monitoring regularly physical fitness in youth is well established for public health issues. The aim of this study was to assess the validity and reliability of the International Fitness Scale questionnaire (IFIS) to assess physical fitness in French children in the school context.

METHODS

A sample of 2 060 children (1054 boys), aged 10.6 ± 0.9 years, participated in the validation study while an independent sample of 366 children (175 boys), aged 9 to 11 years, participated in the assessment of reliability. Physical fitness was measured by a self-report of 5 questions with a 5-point Likert-scale (from very poor to very good) (IFIS), and also measured objectively by 4 field tests: cardiorespiratory fitness, muscular strength, speed/agility and flexibility. For the test-retest reliability assessment, children were instructed to complete the questionnaire twice, 1 week apart.

RESULTS

For all physical fitness components studied, children reporting a good or a very good physical fitness in the IFIS had better results in objective measurements of physical fitness tests compared to children reporting a very poor to an average physical fitness (p<0.001) without or with adjustments for sex, age and weight status. The reliability coefficients were acceptable for all components of physical fitness (0.59-0.72).

CONCLUSIONS

These results suggest that IFIS appears to be a useful instrument for teachers to estimate physical fitness levels of French children, possibly on a large scale.

Development of a genetic risk score to predict the risk of hypertension in European adolescents from the HELENA study

Introduction

From genome wide association study (GWAS) a large number of single nucleotide polymorphisms (SNPs) have previously been associated with blood pressure (BP) levels. A combination of SNPs, forming a genetic risk score (GRS) could be considered as a useful genetic tool to identify individuals at risk of developing hypertension from early stages in life. Therefore, the aim of our study was to build a GRS being able to predict the genetic predisposition to hypertension (HTN) in European adolescents.

Methods

Data were extracted from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) cross-sectional study. A total of 869 adolescents (53% female), aged 12.5-17.5, with complete genetic and BP information were included. The sample was divided into altered (≥130 mmHg for systolic and/or ≥80 mmHg for diastolic) or normal BP. Based on the literature, a total of 1.534 SNPs from 57 candidate genes related with BP were selected from the HELENA GWAS database.

Results

From 1,534 SNPs available, An initial screening of SNPs univariately associated with HTN (p < 0.10) was established, to finally obtain a number of 16 SNPs significantly associated with HTN (p < 0.05) in the multivariate model. The unweighted GRS (uGRS) and weighted GRS (wGRS) were estimated. To validate the GRSs, the area under the curve (AUC) was explored using ten-fold internal cross-validation for uGRS (0.802) and wGRS (0.777). Further covariates of interest were added to the analyses, obtaining a higher predictive ability (AUC values of uGRS: 0.879; wGRS: 0.881 for BMI z-score). Furthermore, the differences between AUCs obtained with and without the addition of covariates were statistically significant (p < 0.05).

Conclusions

Both GRSs, the uGRS and wGRS, could be useful to evaluate the predisposition to hypertension in European adolescents.

New indices in predicting cardiometabolic risk and its relation to endothelial dysfunction in adolescents: The HELENA study

BACKGROUND AND AIMS

Blood pressure (BP) changes and insulin resistance (IR) are important cardiometabolic risk (CMR) factors; their early identification can contribute to the reduction of cardiovascular events in adulthood. This necessitates the search for more accessible and easily applied indicators for their prediction. Therefore, this study aimed to evaluate the predictive power of the indices, TyG, TG/HDL-c, height-corrected lipid accumulation product (HLAP), and visceral adiposity index (VAI), in identifying the CMR obtained by high BP and IR and to verify their relationship with biomarkers of endothelial dysfunction (ED) in European adolescents.

METHODS AND RESULTS

The anthropometric data and blood biomarkers of 744 adolescents (343 boys and 401 girls) from the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study (HELENA-CSS), with a mean age of 14.67 (SD 1.15) years, were assessed. The adolescents were then classified according to the presence or absence of high BP and IR. The cut-off points of the indices evaluated for the identification of CMR were determined. The relationship between CMR diagnosed using these indices and ED biomarkers was tested. The HLAP and TG/HDL-c were fair predictors of CMR obtained by IR in male adolescents. These indices showed association with hsCRP in sVCAM-1 in boys, but it lost significance after adjusting for age and body mass index.

CONCLUSION

TG/HDL-c and HLAP indices showed a fair performance in predicting CMR, obtained by IR, in male adolescents. ED showed no association with the CMR identified by the indices.

Changes in physical activity patterns from adolescence to young adulthood: the BELINDA study

Physical activity (PA) is recognized as a marker of health. The aim was to investigate PA differences from adolescence to young adulthood. European adolescents included in the HELENA study were invited to participate in a follow-up study, 10 years later. The present study included 141 adults (25.0 ± 1.4 years) for whom valid accelerometer data were available in adolescence and adulthood. Changes in PA by sex, weight and maternal education level were explored with interactions. Time spent in sedentary activity, light PA (LPA) and moderate PA (MPA) increased by 39.1, 59.6 and 6.6 min/day, respectively, whereas the time spent in vigorous PA (VPA) decreased by 11.3 min/day compared with adolescent VPA (p < 0.05). Increases in MPA were greater on weekends compared with weekdays, but we found a greater decrease in VPA on weekdays compared with weekends. Moderate-to-vigorous PA (MVPA) decreased significantly on weekdays (-9.6 min/day; 95%CI, -15.9 to -3.4), while it increased on weekends (8.4 min/day; 95%CI, 1.9 to 14.8). Significant heterogeneity was found across sexes for VPA and MVPA, with a stronger decrease in VPA in males compared with females and a significant decrease in MVPA (-12.5 min/day; 95%CI, -20.4 to -4.5) in males but not in females (1.9 min/day; 95%CI, -5.5 to 9.2). No significant heterogeneity was found to be linked to maternal education level or weight, irrespective of PA level.  Conclusion: Our data suggest that the transition from adolescence to young adulthood is a critical period for lifestyle PA habits. A decline in VPA and an increasingly sedentary time were observed. The observed changes are worrying and may increase the risk of developing adverse health consequences later in life. What is Known: • The transition from adolescence to adulthood is marked by many life changes affecting lifestyle habits. Most studies tracking physical activity from adolescence to adulthood were done using PA questionnaires, which is a subjective method. What is New: • Our study bring first data on objective changes in PA patterns between adolescence and young adulthood, taking account of BMI, sex and maternal educational level. Our results suggest that the transition from adolescence to young adulthood is a critical period for lifestyle PA habits, especially for time spent on sedentary activities.

Validation of the IMPACT-III Questionnaire in French Children With Inflammatory Bowel Disease

OBJECTIVES

This study assessed the reliability and validity of the IMPACT-III questionnaire, a health-related quality of life (HRQoL) instrument, in French children with inflammatory bowel disease (IBD).

METHODS

Eighty-four children and adolescents (45 boys, aged 14.3 ± 2.7 years) were included in a validation study of the IMPACT-III questionnaire. Patients completed 2 questionnaires for measuring HRQoL: the IMPACT-III and the Pediatric Quality of Life Inventory 4.0 Generic Core Scale (PedsQL). Internal consistency was assessed using Cronbach α. Factor analysis was performed on data from the IMPACT-III to help construct domains. Concurrent validity was assessed by calculating Spearman correlation coefficients.

RESULTS

Cronbach α for the PedsQL total score was good (0.89). The most robust factor solution was a 3-domain structure: (a) Concerns, (b) Body Image and Physical Condition, and (c) Symptoms and Socializing. All domains had good reliability (0.674-0.863). Only 2 items had to be removed. Discriminant validity was demonstrated by significant differences ( P < 0.001) in median IMPACT-III scores between inactive and active disease for the total score (83.3 vs 72.0), and for Concerns ( P < 0.002) and Symptoms and Socializing ( P < 0.001).

CONCLUSIONS

These results suggest that IMPACT-III appears to be a useful instrument for measuring HRQoL in French children with IBD.

Food portion sizes and their relationship with energy, and nutrient intakes in adolescents: The HELENA study

OBJECTIVES

This study aimed to investigate the associations between portion sizes (PSs) from different food groups and energy, as well as nutrient intakes in European adolescents.

METHODS

A sample of 1631 adolescents (54.2 % girls) were included from the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional (HELENA) study. Mean food PS was calculated by dividing the total intake of the items by the number of eating occasions of these consumed items. To determine the key items for analysis, foods were ranked by frequency of consumption. A one-way between-groups analysis of covariance was used to test for significant differences in means across tertiles. A multivariable linear regression analysis was carried out, adjusting for age, sex, maternal education, body mass index, and using country as a level.

RESULTS

Energy intake increased with elevated intakes of energy-dense foods. Large portions of rice and other grains, starch roots and potatoes, and meat substitutes, nuts, and pulses were associated with increased carbohydrate and fiber intake. Larger portions of cheese and butter and animal fat were significantly associated with a higher fat intake. Lower intakes of some vitamins and micronutrients were noticed with consumption of larger portions of high energy-dense foods, such as desserts and pudding, margarine and vegetable oil, and butter and animal fat.

CONCLUSIONS

Large food PSs may be associated with positive energy, as well as macro- and micronutrient intake. Moreover, the findings from this study may help the future development of dietary guidance in general and specific to PSs, and support targeted strategies to address intakes of certain nutrients in European adolescents.

Safety and adherence of pressure garment therapy in children with upper limb unilateral cerebral palsy. Results from a randomized clinical trial ancillary analysis

Background

This study was conducted to assess the safety and adherence of the use of a PGT (Pressure Garment Therapy) Lycra® sleeve to treat upper limb unilateral cerebral palsy (UCP) in children.

Methods

This study was conducted as a prospective, placebo-controlled, double-blinded, randomized monocenter study. Included in the study were 58 UCP children, 49 of whom were analyzed. 25 children (mean age 6.6 ± 1.6 years; 12 girls) were allocated to the active group vs. 24 (mean age 6.7 ± 1.6 years; 10 girls) in the placebo group. The intervention consisted of an active PGT Lycra® arm sleeve manufactured to generate a homogeneous pressure ranging from 15 to 25 mmHg. The placebo PGT Lycra® sleeve was manufactured to generate a homogeneous pressure under 7 mmHg. The time of wearing period was set at 3 h/day at minimum and 6 h/day at maximum, over the course of 6 months. The main outcome measures were safety outcomes including the number and intensity of Adverse Events of Special Interest (AESIs). AESIs were defined as adverse events imputable to compressive therapy and Lycra® wearing. Level of adherence was expressed in percentage of number of days when the sleeve was worn for at least 3 h per day compared to length of duration in days (start and end date of wearing period).

Results

Frequency of AESIs were very low and no different between groups (4.12 ± 11.32% vs. 1.83 ± 3.38%; p = 0.504). There were no differences in adherence (91.86 ± 13.86% vs. 94.30 ± 9.95%; p = 0.425).

Conclusion

The use of PGT Lycra® arm sleeve in children with UCP is safe and well-tolerated with a very good adherence. The low rate of AESIs is promising for further randomized clinical trials on efficacy.

Changes in (poly)phenols intake and metabolic syndrome risk over ten years from adolescence to adulthood

BACKGROUND AND AIMS

(Poly)phenols might contribute to prevent cardiovascular disease, but limited prospective studies exist among adolescents. This study aimed to evaluate within-subject longitudinal changes in (poly)phenols intakes and food group contributors while also exploring the association with metabolic syndrome risk (MetS) during 10 years of follow up in European adolescents becoming young adults.

METHODS AND RESULTS

In 164 participants (58% girls, 13-18 y at baseline) from Ghent, Zaragoza and Lille, longitudinal data (2006-2016) on (poly)phenol intake was retrieved via 2 or 3 24 h recalls. Linear and logistic longitudinal regression tested the association of (poly)phenols intake (total and classes) with Mets risk or its components (waist-height-ratio, HDL cholesterol, LDL cholesterol, triglycerides, blood pressure and insulin resistance index), adjusted for age, sex, country and other nutrient intakes. The total (poly)phenols intake was 421 ± 107 mg/day (192 mg/1000 kcal/day) at baseline, while 610 ± 101 mg/day (311 mg/1000 kcal/day) at follow-up. The three major food sources for (poly)phenols were 'chocolate', 'fruit and vegetable juices', 'cakes and biscuits' during adolescence and 'coffee', 'tea' and 'chocolate' during adulthood. Phenolic acid intake was associated with less LDL increase over time, while stilbene intake with a steeper increase in triglycerides over time.

CONCLUSIONS

Differences in major (poly)phenols contributors over time were partially explained by age-specific dietary changes like increased coffee and tea during adulthood. Some significant (poly)phenols-MetS associations might argue for nutrition-based disease prevention during adolescence, especially since adolescents had low (poly)phenols intake.

Change in physical fitness due to the COVID-19 pandemic lockdown in French adolescents: a comparison between two independent large samples from Diagnoform battery

Numerous studies reported a significant decline in physical activity level in adolescents as a result of the COVID-19 lockdown. Physical fitness is recognized as a powerful marker of health in youth. The aim of this study was to evaluate the impact of the COVID-19 pandemic lockdown on health-related physical fitness in French adolescents. Two cross-sectional studies were performed comparing two different groups of French adolescents, before (sample 1) and after the first lockdown (sample 2). A total of 1231 adolescents (aged to 16.5 ± 1.5 years) participated in the two cross-sectional studies. Complete data for physical fitness and anthropometrics data were obtained. Adolescents from sample 2 showed lower physical fitness levels compared to adolescents from sample 1. Regarding physical fitness for boys and girls, physical fitness levels were significantly lower in both sex between adolescents from the sample 1 and adolescents from the sample 2, except for cardiorespiratory fitness and flexibility for boys and girls, respectively. The physical fitness global score was also significantly lower between adolescents from the sample 1 and 2 for boys (-9.8%, p < 0.01) and girls (-16.2%; p < 0.01), respectively. Overall, the higher difference was found for performance in the speed body displacement test (-30%). A difference of 12.8% and 25% was observed for boys and girls, respectively.   Conclusion: COVID-19 pandemic lockdown had a negative impact on physical fitness in French youth. This study highlights the need to develop, in a near future, prevention programmes in order to improve the physical fitness in youth. What is Known: • COVID-19 pandemic deeply impacted lifestyle habits. A worrying decrease of physical activity, associated to a dramatic increase of time spent in sedentary behaviors was found in many coutries. What is New: • Our study bring first data on the health-related physical fitness consequences due to lockdown in French adolescents. Our study demonstrate the negative impact of COVID-19 pandemic lockdown on health-related physical fitness in French adolescents.

High Fructose Intake Contributes to Elevated Diastolic Blood Pressure in Adolescent Girls: Results from The HELENA Study

BACKGROUND

The association between high fructose consumption and elevated blood pressure continues to be controversial, especially in adolescence. The aim of this study was to assess the association between fructose consumption and elevated blood pressure in an European adolescent population.

METHODS

A total of 1733 adolescents (mean ± SD age: 14.7 ± 1.2; percentage of girls: 52.8%) were analysed from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study in eight European countries. Blood pressure was measured using validated devices and methods for measuring systolic blood pressure (SBP) and diastolic blood pressure (DBP). Dietary data were recorded via repeated 24 h recalls (using specifically developed HELENA-DIAT software) and converted into pure fructose (monosaccharide form) and total fructose exposure (pure fructose + fructose from sucrose) intake using a specific fructose composition database. Food categories were separated at posteriori in natural vs. were non-natural foods. Elevated BP was defined according to the 90th percentile cut-off values and was compared according to tertiles of fructose intake using univariable and multivariable mixed logistic regression models taking into account confounding factors: centre, sex, age and z-score-BMI, MVPA (Moderate to Vigorous Physical Activity) duration, tobacco consumption, salt intake and energy intake.

RESULTS

Pure fructose from non-natural foods was only associated with elevated DBP (DBP above the 10th percentile in the highest consuming girls (OR = 2.27 (1.17-4.40); p = 0.015) after adjustment for cofounding factors.

CONCLUSIONS

Consuming high quantities of non-natural foods was associated with elevated DBP in adolescent girls, which was in part due to high fructose levels in these foods categories. The consumption of natural foods containing fructose, such as whole fruits, does not impact blood pressure and should continue to remain a healthy dietary habit.

Daily physical activity patterns in children and adolescents with inflammatory bowel disease

BACKGROUND

The aim of this study was to assess PA patterns among children and adolescents with inflammatory bowel disease (IBD).

METHODS

Sixty participants with IBD (42 Crohn's disease [CD], 10 ulcerative colitis [UC], and 8 IBD-unclassified [IBD-U], 30 male patients) in remission (n = 45) or with mild disease (n = 15) were compared with 60 healthy age- and sex-matched controls. Each participant wore a triaxial accelerometer during 4 consecutive days for objective daily PA quantification.

RESULTS

Overall, there was no significant difference in daily PA patterns between patients with IBD and healthy controls, with 31.7% of patients with IBD and 38.3% of healthy controls fulfilling the recommendation of 60 min of moderate-to-vigorous physical activity (MVPA) daily (NS). Male patients with IBD spent significantly less time in MVPA compared with matched healthy controls (mean difference, 16.2 min day^-1; p < 0.05). No difference was observed for female patients with IBD. No difference in sedentary pattern between male patients with IBD and controls was found.

CONCLUSIONS

Children and adolescents with inactive or mildly active IBD have similar PA patterns compared with healthy controls, except for male patients who have reduced moderate-to-vigorous PA. By far, most patients with IBD do not fulfill the MVPA recommendations for health benefits.

IMPACT

There is few data on PA patterns in pediatric patients with IBD. Methodological issues to assess PA limit the strengths of these studies. Pediatric IBD patients with inactive or mildly active IBD have similar physical activity patterns compared with healthy controls, except for male patients who have reduced moderate-to-vigorous PA. Most patients with IBD do not fulfill the MVPA recommendations for health benefits.

School time is associated with cardiorespiratory fitness in adolescents: The HELENA study

We assessed the association between school time and physical fitness in adolescents. The study included 2,024 adolescents, aged 12.5-17.5 years, who participated in the Healthy Lifestyle in Europe by Nutrition in Adolescence study. Health-related physical fitness components were assessed using the physical fitness tests battery. Cardiovascular risk was categorized using the sex-specific cut-offs for a healthy cardiorespiratory fitness level in adolescents proposed by FitnessGram®. School time was classified as short or long. Multivariate analysis accounted for confounding factors such age, sex, body mass index, time spent in moderate to vigorous physical activity, pubertal status, and parents' educational level. Cardiorespiratory fitness was higher in adolescents with a long school time than in those with a short school time (42.0 ± 7.6 vs 40.7 ± 7.2 mL.kg^-1.min^-1, respectively; p < 0.05). The percentage of adolescents at cardiovascular risk in adulthood was higher in the short than in the long time group (45.2% vs 31.7%, respectively) (p < 0.05). These findings suggest that a long school day is associated with higher cardiorespiratory fitness in adolescents and that school time should be considered in interventions and health promotion strategies.

Cardiometabolic Risk is Positively Associated with Underreporting and Inversely Associated with Overreporting of Energy Intake Among European Adolescents: The Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) Study

BACKGROUND

Dietary misreporting is the main limitation of dietary assessments and has been associated with BMI during youth. However there are no prior studies assessing misreporting and cardiometabolic risks (CMRs) in adolescence.

OBJECTIVES

To examine the associations between dietary misreporting and CMR factors in adolescents and to assess the potential bias in the association between CMR and energy intake (EI) driven by dietary misreporting.

METHODS

Two 24-hour dietary recalls were obtained from 1512 European adolescents (54.8% girls) aged 12.5-17.5 years. Physical activity was measured by accelerometry. Cut-offs suggested by Huang were applied to identify misreporters. Height, waist circumference (WC), the sum of 4 skinfold thicknesses, diastolic blood pressure (DBP), systolic blood pressure (SBP), and cardiorespiratory fitness (CRF) measurements were taken and serum triglycerides and total-/high-density lipoprotein cholesterol ratio were analyzed. A sex- and age-specific clustered CMR score (n = 364) was computed. Associations were investigated by multilevel regression analyses adjusting for age, sex, center, socioeconomic status, and physical activity.

RESULTS

Underreporting (24.8% adolescents) was significantly (P < 0.05) associated with a higher WC, waist-to-height ratio (WHeR), and sum of skinfold thickness, whereas overreporting (23.4% adolescents) was significantly associated with a lower WC, WHeR, sum of skinfold thickness, and SBP. Associations between CMR factors and EI were significantly affected by misreporting, considering various approaches. Significant, positive associations became inverse after adjusting for misreporting for WC and WHeR. The opposite was true for the sum of skinfold thickness, SBP, and CMR score. The associations between EI and DBP and CRF did not remain significant after adjusting for misreporting.

CONCLUSIONS

CMR factors differed among misreporting groups, and both abdominal and total fat mass indicators were more strongly associated with all forms of misreporting than was BMI. Moreover, misreporting seems to bias EI and CMR associations in adolescents. Therefore, energy misreporting should be taken into account when examining diet-CMR associations.

Free Sugar Consumption and Obesity in European Adolescents: The HELENA Study

Few studies have evaluated the association between dietary free sugars intake (FSI) and obesity in adolescents. We examined the relation between FSI and their contributors from the main food groups and obesity in European adolescents. We included 843 adolescents (51.6% male) from the cross-sectional HELENA study with two completed 24 h recalls and anthropometric data. Linear mixed models were applied to investigate the relation between FSI and different anthropometric indices. Odds ratios for having a high body mass index (BMI) were also estimated by multilevel ordinal regression. Total FSI was higher in males than females (102.60 g and 87.58 g, respectively, p < 0.001). No effect was observed between free sugar from the main food groups and BMI. Consumers of FSI from "cakes, pies and biscuits" in males (odd ratio (OR) = 0.455; 95% Confidence interval (CI) 0.251, 0.824) and from "breakfast cereals" in females had a lower probability of having obesity (OR = 0.423; 95%CI 0.204, 0.878), whereas females consuming FSI from 'fruit and vegetables juices' had a higher probability of obesity (OR= 2.733; 95% CI 1.286, 5.810). This study provides no evidence that increased FSI is associated with obesity in adolescents. Further studies are needed to assess the longitudinal exposure to FSI and their effect on obesity development.

Single nucleotide polymorphisms of ADIPOQ gene associated with cardiovascular disease risk factors in European adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence study

OBJECTIVES

Cardiovascular diseases (CVDs) are responsible of 31% of all deaths worldwide. Genetic predisposition to CVDs in adolescents remains largely unknown. Aims of present research are to examine the association of ADIPOQ gene polymorphisms with cardiovascular disease risk factors in European adolescents.

METHODS

A total of 14 polymorphisms in the ADIPOQ gene were genotyped in 1057 European adolescents (12-18 years old) from the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study. We measured serum lipids and a CVD risk score, along with weight, height, triceps, and subscapular skinfold thickness, leptin, insulin and other markers of glucose regulation.

RESULTS

The rs822393, rs822395 and rs7649121 polymorphisms of ADIPOQ gene were significantly associated with several CVD risk factors [i.e. high-density lipoprotein cholesterol (HDL-C), apolipoprotein (Apo) A1, SBP and CVD risk score] in European adolescents. We also found an association of the TGAAGT ADIPOQ haplotype (rs822393, rs16861210, rs822395, rs822396, rs12495941 and rs7649121) with HDL-C and ApoA1 levels.

CONCLUSION

Several individual polymorphisms (rs822393, rs822395 and rs7649121) and a haplotype of ADIPOQ gene were significantly associated with cardiovascular disease risk factors in European adolescents.

Severe preschool asthmatics have altered cytokine and anti-viral responses during exacerbation

BACKGROUND

Preschool asthma/recurrent wheeze is a heterogeneous condition. Different clinical phenotypes have been described, including episodic viral wheeze (EVW), severe intermittent wheeze (SIW), and multiple-trigger wheeze (MTW).

OBJECTIVE

To compare clinical, viral, and inflammatory/immune profiling at exacerbation between MTW, SIW, and EVW phenotypes.

METHODS

Multicenter, prospective, observational cohort (VIRASTHMA-2). Children (1-5 years) with preschool asthma were enrolled during hospitalization for a severe exacerbation. History and anamnestic data, plasma, and nasal samples were collected at exacerbation (T1) and at steady state, 8 weeks later (T2), and sputum samples were collected at T1.

RESULTS

A total of 147 children were enrolled, 37 (25%) had SIW, 18 (12.2%) EVW, and 92 (63%) MTW. They were atopic (47%), exposed to mold (22%) and cigarette smoke (50%), and prone to exacerbations (≥2 in the previous year in 70%). At exacerbation, at least one virus was isolated in 94% and rhinovirus in 75%, with no difference between phenotypes. Children with MTW and SIW phenotypes displayed lower plasma concentrations of IFN-γ (P = .002), IL-5 (P = .020), TNF-α (P = .038), IL-10 (P = .002), IFN-β (P = .036), and CXCL10 (P = .006) and lower levels of IFN-γ (P = .047) in sputum at exacerbation than children with EVW. At T2, they also displayed lower plasma levels of IFN-γ (P = .045) and CXCL10 (P = .013).

CONCLUSION

Among preschool asthmatic children, MTW and SIW, prone to exacerbations, display lower systemic levels of Th1, Th2 cytokines, pro- and anti-inflammatory cytokines, and antiviral responses during severe virus-induced exacerbation.

Association between lipoprotein lipase gene polymorphisms and cardiovascular disease risk factors in European adolescents: The Healthy Lifestyle in Europe by Nutrition in Adolescence study

OBJECTIVES

To examine the association of lipoprotein lipase (LPL) polymorphisms with cardiovascular disease (CVD) risk factors in European adolescents, along with the influence of physical activity on these associations.

METHODS

A total of 13 LPL polymorphisms were genotyped in 1.057 European adolescents (12-18 years old) from the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study. Serum lipids, glucose, insulin, and leptin (LEP) levels were measured and a CVD risk score was computed. We also measured body weight and height, waist and hip circumferences, and triceps and subscapular skinfold thickness. Physical activity was objectively measured by accelerometry for 7 days.

RESULTS

The rs1534649, rs258, rs320, and rs328 polymorphisms were associated with several CVD risk factors (ie, body mass index, triglycerides [TG], LEP, and cholesterol/high-density lipoprotein [HDL], low-density lipoprotein [LDL]/HDL, TG/HDL ratios). TG and TG/HDL were associated with haplotype blocks 3 (rs282, rs285 polymorphisms) and 4 (rs3126, rs320, rs328, rs10099160 polymorphisms), being the latter also associated with the CVD risk score. Physical activity modulated the association of adiposity with rs1534649 and rs258 polymorphisms.

CONCLUSIONS

Polymorphisms rs1534649, rs258, rs320 and rs328, and two haplotypes of LPL were significantly associated with CVD risk factors in European adolescents. Higher levels of moderate to vigorous physical activity may attenuate the effects of rs1534649 and rs258 polymorphisms on adiposity.

Fermented infant formula (with Bifidobacterium breve C50 and Streptococcus thermophilus O65) with prebiotic oligosaccharides is safe and modulates the gut microbiota towards a microbiota closer to that of breastfed infants

BACKGROUND & AIMS

Microbiome-modulators can help positively steer early-life microbiota development but their effects on microbiome functionality and associated safety and tolerance need to be demonstrated. We investigated the microbiome impact of a new combination of bioactive compounds, produced by the food-grade microorganisms Bifidobacterium breve C50 and Streptococcus thermophilus ST065 during a fermentation process, and prebiotics in an infant formula. Tolerance and safety were also assessed.

METHODS

An exploratory prospective, randomized, double-blind, controlled, multi-centre study was designed to investigate the effect of bioactive compounds and prebiotics (short-chain galacto-oligosaccharides (scGOS)/long-chain fructo-oligosaccharides (lcFOS) 9:1). Experimental formulas containing these bioactive compounds and prebiotics (FERM/scGOS/lcFOS), prebiotics (scGOS/lcFOS), or bioactive compounds (FERM), were compared to a standard cow's milk-based control formula (Control). Exclusively breastfed infants were included as a reference arm since exclusive breastfeeding is considered as the optimal feeding for infants. The study lasted six months and included visits to health care professionals at baseline, two, four and six months of age. Stool SIgA concentration was the primary study outcome parameter.

RESULTS

There were 280 infants randomized over the experimental arms and 70 infants entered the breastfed-reference arm. Demographics were balanced, growth and tolerance parameters were according to expectation and adverse events were limited. At four months of age the median SIgA concentration in the FERM/scGOS/lcFOS group was significantly higher compared to the Control group (p = 0.03) and was more similar to the concentrations found in the breastfed-reference group. Bifidobacterium increased over time in all groups. The FERM/scGOS/lcFOS combination resulted in a microbiota composition and metabolic activity closer to the breastfed infants' microbiome.

CONCLUSION

The FERM/scGOS/lcFOS combination showed a significant positive effect on SIgA levels. All formulas tested were associated with normal growth and were well-tolerated. Additionally, at four months of age the FERM/scGOS/lcFOS formula brought the microbiome composition and metabolic activity closer towards that of breastfed infants.

CLINICAL TRIAL REGISTRY

Registration number NTR2726 (Netherlands Trial Register; www.trialregister.nl/).

Association between CNTF Polymorphisms and Adiposity Markers in European Adolescents

OBJECTIVE

To examine the association between polymorphisms of the ciliary neurotrophic factor gene (CNTF) and total and central adiposity markers in adolescents.

STUDY DESIGN

This cross-sectional study involved 1057 European adolescents aged 12-18 years enrolled in the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study. Five polymorphisms of CNTF were genotyped, and the weight, height, waist and hip circumference, and triceps and subscapular skinfold thickness of the subjects were measured and recorded.

RESULTS

The T allele of rs2509914, the C allele of rs2515363, and the G allele of rs2515362 were significantly associated (after Bonferroni correction) with higher values for several adiposity markers under different inheritance models. The CNTF CCGGA haplotype (rs2509914, rs17489568, rs2515363 rs1800169, and rs2515362) was also significantly associated with lower body mass index, waist circumference, waist/height ratio, and waist/hip ratio values compared with the TCCGG haplotype under several inheritance models.

CONCLUSIONS

Three polymorphisms-rs2509914, rs2515363, and rs2515362-and the CCGGA haplotype of CNTF were significantly associated with adiposity in European adolescents. These results suggest the potential role of CTNF in the development of obesity-related phenotypes.

Physical activity is associated with improved bone health in children with inflammatory bowel disease

BACKGROUND & AIMS

Bone health is an important concern in patients with inflammatory bowel disease (IBD). Low bone mineral density (BMD) is a powerful predictor of fracture risk in IBD patients. Physical activity (PA) plays an important role in bone health. However, PA data for children and adolescents with IBD are scarce. The primary aim is to evaluate the relationship between PA and BMD in children with IBD. The secondary aim was to assess the relationship between PA and quality of life.

METHODS

Eighty-four IBD paediatric patients (45 boys) aged 14.3 ± 2.7 years were included (disease activity: (i) remission, n = 62; (ii) mild, n = 18; (iii) severe disease, n = 1). BMD was measured using dual-energy X-ray absorptiometry and expressed as age- and sex-based Z-scores. Each patient wore a triaxial accelerometer for seven consecutive days for objective PA quantification. Quality of life was assessed using the PedsQL™ and energy intake was assessed prospectively for three days using a dietary diary.

RESULTS

BMD Z-score was -0.96 ± 1.11. Only five patients (6%) fulfilled the recommendation of 60 min of daily moderate-to-vigorous PA (MVPA). The proportion of children with osteopenia and osteoporosis was 51% and 4%, respectively. After adjustment for confounders (pubertal status and body mass index), total PA and time in MVPA were positively associated with BMD (regression coefficient per one standard deviation increase in PA parameters = 0.26; P < 0.05). There was no association between time spent in MVPA and total PA, and total quality of life score.

CONCLUSIONS

PA likely is associated with improved bone health in IBD children. Intervention studies investigating a causal relationship between PA and BMD in paediatric patients with IBD are warranted.

Comparison and validation of accelerometer wear time and non-wear time algorithms for assessing physical activity levels in children and adolescents

Background

Accelerometers are widely used to measure sedentary time and daily physical activity (PA). However, data collection and processing criteria, such as non-wear time rules might affect the assessment of total PA and sedentary time and the associations with health variables. The study aimed to investigate whether the choice of different non-wear time definitions would affect the outcomes of PA levels in youth.

Methods

Seventy-seven healthy youngsters (44 boys), aged 10–17 years, wore an accelerometer and kept a non-wear log diary during 4 consecutives days. We compared 7 published algorithms (10, 15, 20, 30, 60 min of continuous zeros, Choi, and Troiano algorithms). Agreements of each algorithm with the log diary method were assessed using Bland-Altmans plots and by calculating the concordance correlation coefficient for repeated measures.

Results

Variations in time spent in sedentary and moderate to vigorous PA (MVPA) were 30 and 3.7%. Compared with the log diary method, greater discrepancies were found for the algorithm 10 min (p < 0.001). For the time assessed in sedentary, the agreement with diary was excellent for the 4 algorithms (Choi, r = 0.79; Troiano, r = 0.81; 30 min, r = 0.79; 60 min, r = 0.81). Concordance for each method was excellent for the assessment of time spent in MVPA (> 0.86). The agreement for the wear time assessment was excellent for 5 algorithms (Choi r = 0.79; Troiano r = 0.79; 20 min r = 0.77; 30 min r = 0.80; 60 min r = 0.80).

Conclusions

The choice of non-wear time rules may considerably affect the sedentary time assessment in youth. Using of appropriate data reduction decision in youth is needed to limit differences in associations between health outcomes and sedentary behaviors and may improve comparability for future studies. Based on our results, we recommend the use of the algorithm of 30 min of continuous zeros for defining non-wear time to improve the accuracy in assessing PA levels in youth.

Trial registration

NCT02844101 (retrospectively registered at July 13th 2016).

Electronic supplementary material

The online version of this article (10.1186/s12874-019-0712-1) contains supplementary material, which is available to authorized users.

Gender influences physical activity changes during adolescence: The HELENA study

BACKGROUND

We compared differences in physical activity (PA) between pre/mid-pubertal and post-pubertal participants according to gender.

METHODS

The study included a total of 1842 healthy participants aged 12.5-17.4 years, who participated in the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study. Participants wore a uniaxial accelerometer (ActiGraph© GT1M, Pensacola, FL, USA) attached to their lower back for seven consecutive days to measure PA. Pubertal status was assessed by physical examination and the population was classified as pre/mid-pubertal (Tanner stages 1-3) or post-pubertal (Tanner stages 4-5). PA was compared between these groups according to gender during the whole week, on school-free days and on school days, before and after school, and during lessons and recesses.

RESULTS

When comparing the pre/mid-pubertal group with the post-pubertal group, girls' total PA did not differ between groups. However, a slight difference was observed in boys, among whom PA on school-free days showed a difference of 17.6% between the pre/mid-pubertal group and the post-pubertal group (679 kcounts vs 564 kcounts, respectively; P = 0.0007) and 20% (162 kcount vs 135 kcounts; P = 0.006) for school recess. There was no difference among girls.

CONCLUSIONS

A reduced level of PA in the post-pubertal groups was only observed in boys during non-organized times such as on school-free days and during school recesses, with a moderate impact on total PA.

Physical Fitness Reference Standards in French Youth: The BOUGE Program

The aim of this study was to establish sex- and age-specific physical fitness percentiles in French youth. A sample of 11,186 children and adolescents (5,546 boys and 5,640 girls), aged between 10 and 15 years, was assessed in the French national BOUGE study. Participants were tested for their cardiorespiratory fitness, muscular endurance, speed, flexibility, and agility using the following tests: 20-m shuttle run tests, curl-ups test, 50-m sprint test, back-saver sit and reach test, and 10 × 5-m shuttle run test. Percentile values were estimated for French youth as a function of age stratified by sex using the generalized additive model for location, scale, and shape (GAMLSS). In general, physical fitness was better in boys than in girls, except for the back-saver sit and reach test, in which girls performed better. Except for the back-saver sit and reach test and 10 × 5-m shuttle run test, physical fitness performance was significantly associated with age. Sex- and age-specific normative values for physical fitness tests in French youth expressed as percentiles from the fifth to the 95th are provided. Reference values provide normative data for French youth. The data are useful in identifying special needs for appropriate intervention programs.

Awareness of wearing an accelerometer does not affect physical activity in youth

BACKGROUND

This study aimed to investigate whether awareness of being monitored by an accelerometer has an effect on physical activity in young people.

METHODS

Eighty healthy participants aged 10-18 years were randomized between blinded and nonblinded groups. The blinded participants were informed that we were testing the reliability of a new device for body posture assessment and these participants did not receive any information about physical activity. In contrast, the nonblinded participants were informed that the device was an accelerometer that assessed physical activity levels and patterns. The participants were instructed to wear the accelerometer for 4 consecutive days (2 school days and 2 school-free days).

RESULTS

Missing data led to the exclusion of 2 participants assigned to the blinded group. When data from the blinded group were compared with these from the nonblinded group, no differences were found in the duration of any of the following items: (i) wearing the accelerometer, (ii) total physical activity, (iii) sedentary activity, and (iv) moderate-to-vigorous activity.

CONCLUSIONS

Our study shows that the awareness of wearing an accelerometer has no influence on physical activity patterns in young people. This study improves the understanding of physical activity assessment and underlines the objectivity of this method.

TRIAL REGISTRATION

NCT02844101 (retrospectively registered at July 13th 2016).

Physical activity awareness of European adolescents: The HELENA study

The aim of this study was to assess physical activity (PA) awareness of adolescents and to identify anthropometric and psychosocial factors that can lead to under or overestimation of PA. This study included 2044 adolescents. Participants wore a uniaxial accelerometer for 7 days to measure PA and completed a self-rated questionnaire about PA. Adolescents were classified into four PA awareness subgroups (realistically active, overestimators, underestimators and realistically inactive) according to the self-rated and objective assessment of PA. Characteristics and psychosocial factors of the self-rated physically active groups were compared using bivariate and multivariate mixed logistic regression models. Forty-five percent of adolescents reported their PA levels correctly (34.8% realistically active and 10.1% realistically inactive). Among the 59.4% who were objectively inactive, 82.9% tended to overestimate their PA level. Adolescents who overestimated their PA level were older (P < .05), had more support from mother and a best friend (P < .05) and had higher cardiorespiratory fitness (P < .001) compared with those who were realistically active. A significant number of adolescents believe that they are physically active when they are not. Improving awareness, especially in the high-risk groups identified here, might help to bring about behavioural changes in physically inactive adolescents.

Do adolescents accurately evaluate their diet quality? The HELENA study

BACKGROUND & AIMS

The aim of this study was to assess the diet quality awareness and associated factors in a large sample of European adolescents.

METHODS

The study included 3389 healthy adolescents, aged 12.5-17.5 years, who participated in the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) Study. The adolescents' diet quality was based on repeated 24 h recalls and scored into a Diet Quality Index for Adolescents (DQI-A) considering four components: meal, equilibrium, diversity and quality. A self-rated diet quality questionnaire was administered to adolescents to assess their dietary awareness. The association of DQI-A with dietary awareness was studied using a linear mixed model including the center as the random effect and dietary awareness as the fixed effect.

RESULTS

There was a positive association between DQI-A scores and diet quality perception levels (p < 0.0001). The mean DQI-A was 59.0 (SD = 14.8) in adolescents with a low dietary awareness compared with 65.4 (SD = 12.6) in adolescents with high dietary awareness (p < 0.0001). Similar results were found for all the DQI components. When analyses were stratified, we found a significant heterogeneity across the nutritional status, with no significant association between DQI-A and dietary awareness level in obese adolescents, but a positive association in overweight, normal and undernourished groups. We found also a significant heterogeneity associated with the lunch location (school or home). No other factor affected dietary awareness (gender, pubertal status and maternal educational level).

CONCLUSION

European adolescents evaluate well their food quality whatever their pubertal status, gender and parental educational level, except for the obese who are not able to assess their diet quality. Improving the dietary awareness in obese adolescents might help to induce behavioral changes.

[Physical fitness levels in French adolescents: The BOUGE program]

BACKGROUND

A high level of physical fitness is associated with cardiovascular health in adolescents. The aims of this study were to assess the levels of physical fitness of French adolescents and to determine the prevalence of these adolescents below the minimum level of cardiorespiratory fitness needed to guarantee future favorable cardiovascular profile.

METHODS

Participants were 12,082 French children and adolescents (5975 boys, 6107 girls) aged to 9 from 16 years. Cardiorespiratory fitness, muscular endurance, speed, flexibility and speed agility were tested. The associations of physical fitness measures with adolescent's characteristics were analyzed using Student t test, one-way ANOVA, or Pearson correlations as appropriate.

RESULTS

Boys were physically fitter than girls, expected for flexibility (P<0.0001). Subjects of normal weight adolescents had significantly better results than overweight or obese adolescents (P<0.05 for all comparisons), but also in comparison with underweight adolescents for muscular endurance, flexibility, cardiorespiratory fitness test (P<0.05). Our findings indicate that, on the basis of cardiorespiratory fitness, 16% of French boys and 7.7% of French girls have a risk of future cardiovascular disease (P<0.0001). This subgroup also performed poorly in all other tests of physical fitness used (P<0.0001). Aerobic fitness decreased significantly with the age (r=-0.168 for boys; r=-0.261 for girls).

CONCLUSIONS

Our results indicate that the physical fitness of French adolescents must be improved to help protect against cardiovascular disease in adulthood, especially in boys. The study showed also a dramatically decrease of the cardiorespiratory fitness during the adolescence period. Developing and introducing a health promotion curriculum in the French schools is suggested to improve health and physical fitness.

Relationship between school rhythm and physical activity in adolescents: the HELENA study

The aim was to assess the relationship between school rhythm and physical activity (PA) in adolescents. The study included 2024 adolescents (12.5-17.4 years). Participants wore an accelerometer for 7 days. A short school rhythm was defined as a short time at school with short recesses and less time in teaching per day (Group 1). A long school rhythm was defined as a longer time at school with more time in teaching and recess (Group 2). Adolescents in Group 1 performed less moderate to vigorous PA (MVPA) than those in Group 2 per week (P < .0001), especially during school days (recess: 3.9 ± 4.0 vs. 9.8 ± 7.9 min · day^-1; P < .0001; teaching hours: 14.5 ± 9.8 vs. 19.1 ± 12.0 min · day^-1; P < .0001). Adolescents in Group 1 were less likely to meet the PA recommendations than were adolescents in Group 2: 30.7% vs. 34.1% (P < .0001). During school days, the percentage of adolescents who spent more than 2 h · day^-1 in sedentary activities was greater in the Group 1 (P < .001). Our results suggest that leisure-time out-of-school hours is used mainly for sedentary activities, and that school time provides a good opportunity for promoting PA.

Doubling diet fat on sugar ratio in children with mitochondrial OXPHOS disorders: Effects of a randomized trial on resting energy expenditure, diet induced thermogenesis and body composition

BACKGROUND & AIMS

Mitochondrial OXPHOS disorders (MODs) affect one or several complexes of respiratory chain oxidative phosphorylation. An increased fat/low-carbohydrate ratio of the diet was recommended for treating MODs without, however, evaluating its potential benefits through changes in the respective contributions of cell pathways (glycolysis, fatty acid oxidation) initiating energy production. Therefore, the objective of the present work was to compare Resting Energy Expenditure (REE) under basal diet (BD) and challenging diet (CD) in which fat on sugar content ratio was doubled. Diet-induced thermogenesis (DIT) and body compositions were also compared. Energetic vs regulatory aspects of increasing fat contribution to total nutritional energy input were essentially addressed through measures primarily aiming at modifying total fat amounts and not the types of fats in designed diets.

METHODS

In this randomized cross-over study, BD contained 10% proteins/30% lipids/60% carbohydrates (fat on sugar ratio = 0.5) and was the imposed diet at baseline. CD contained 10% proteins/45% lipids/45% carbohydrates (fat on sugar ratio = 1). Main and second evaluation criteria measured by indirect calorimetry (QUARK RMR^®, Cosmed, Pavona; Italy) were REE and DIT, respectively. Thirty four MOD patients were included; 22 (mean age 13.2 ± 4.7 years, 50% female; BMI 16.9 ± 4.2 kg/m²) were evaluated for REE, and 12 (mean age 13.8 ± 4.8 years, 60% female; BMI 17.4 ± 4.6 kg/m²) also for DIT. OXPHOS complex deficiency repartition in 22 analysed patients was 55% for complex I, 9% for complex III, 27% for complex IV and 9% for other proteins.

RESULTS

Neither carry-over nor period effects were detected (p = 0.878; ANOVA for repeated measures). REE was similar between BD vs CD (1148.8 ± 301.7 vs 1156.1 ± 278.8 kcal/day; p = 0.942) as well as DIT (peak DIT 260 vs 265 kcal/day; p = 0.842) and body composition (21.9 ± 13.0 vs 21.6 ± 13.3% of fat mass; p = 0.810).

CONCLUSION

Doubling diet fat on sugar ratio does not appear to improve, per se, energetic status and body composition of patients with MODs.

Physical activity using wrist-worn accelerometers: comparison of dominant and non-dominant wrist

The purpose of this study was to determine whether there is a difference in physical activity assessment between a wrist-worn accelerometer at the dominant or non-dominant arm. The secondary purpose was to assess the concurrent validity of measures of physical activity from the wrist-worn accelerometer and the waist-worn accelerometer. Forty adults wore three accelerometers simultaneously, one on the waist and one each on the non-dominant wrist and dominant wrist, respectively, for 24 consecutive hours of free-living conditions. Data were uploaded from the monitor to a computer following a 1-day test period. There were no significant differences in physical activity when comparing the dominant versus the non-dominant wrist, regardless of axis (P>0·05). Mean daily accelerometer output data from both wrists were strongly correlated with average counts per minute from the ActiGraph worn around the waist (r = 0·88, P<0·001). Findings suggest that the choice to wear the accelerometer on the non-dominant or dominant wrist has no impact on results. Data from this study contribute to the knowledge of how to best assess physical activity habits.

Physical Activity Is Associated with Attention Capacity in Adolescents

OBJECTIVE

To assess the relationships among physical activity, measured objectively, and attention capacity in European adolescents.

STUDY DESIGN

The study included 273 adolescents, aged 12.5-17.5 years, who participated in the Healthy Lifestyle in Europe by Nutrition in Adolescence Study. Participants wore a uniaxial accelerometer for 7 days to measure physical activity. The d2 Test of Attention was administered to assess attention capacity. Multivariate analyses were used to study the association of attention capacity with each measure of physical activity. Receiver operating characteristic analysis was performed to determine thresholds that best discriminate between low and good attention capacity.

RESULTS

After controlling for potential confounding variables (age, sex, body mass index, parental educational level, fat mass, aerobic fitness, and center), adolescents' attention capacity test performances were significantly and positively associated with longer time spent in moderate or moderate-to-vigorous physical activity (MVPA) in free-living conditions (P < .05). Receiver operating characteristic curve analyses revealed that the physical activity thresholds that best discriminated between low/good attention capacities were ≥41 min·day(-1) for moderate, ≥12 min·day(-1) for vigorous, and ≥58 min·day(-1) for MVPA.

CONCLUSION

These findings suggest that promoting MVPA may be have a beneficial effect on attention capacity, an important component of cognition, in adolescents.

[Assessment of nutritional status in pediatric ambulatory research]

Nutritional status, an important measure in health promotion and certain childhood and adolescent pathologies, includes anthropometric, diet and physical activity evaluation. Choosing the best assessment of nutritional status for your research must consider objectives of clinician, study design, number of subjects, frequency of measurement, and cost. The purpose of this paper is to present reliable and valid field techniques available for pediatric ambulatory clinical research. These techniques do not interfere with free living conditions and represent a good alternative compared to reference assessment. The techniques are compatible with the quality assurance and ethics in clinical and epidemiological research requirements.

[BOUGE-fitness test battery: health-related field-based fitness tests assessment in children and adolescents]

Physical fitness is an important determinant of global health in children and adolescents. Key components of physical fitness include cardiorespiratory fitness, flexibility, speed, and muscular and endurance strength. The school environment provides a great opportunity to assess the physical fitness level in children and adolescents. The french national program "Bouge... Une priorité pour ta santé! "(Move ... A priority for your health!) aims to assess the physical fitness of children and adolescents aged 6 to 18 years old in French schools. The aim of this paper is to describe the interest to assess different health-related physical fitness components. It presents the chosen tests within said battery for children and adolescents and explains how the battery was conceived. The health-related physical fitness tests included in "BOUGE" were chosen for their validity, reliability, low cost and feasibility for all schools.

A favorable built environment is associated with better physical fitness in European adolescents

OBJECTIVE

To assess the association between the built environment and physical fitness and physical activity in adolescents.

METHODS

The study included 3528 adolescents, aged 12.5-17.5 years, who participated in the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study. The health-related physical fitness components were assessed using the physical fitness tests. Participants wore a uniaxial accelerometer (ActiGraph®) for 7 days to measure physical activity. A specific questionnaire addressing the built environment was used. Potential confounding factors including age, gender, body mass index, body composition, pubertal status, smoking, educational level of parents, and socioeconomic status were analyzed using backward stepwise linear regression analysis.

RESULTS

Heavy traffic in the neighborhood was the strongest factor negatively associated with both physical fitness and physical activity (both P<0.05). Conversely, a secure bicycling or walking route from home to school was positively associated with various components of physical fitness and physical activity (P<0.01). Outdoor fields and gymnasiums near home were also associated with better physical fitness (P<0.01), but not with physical activity.

CONCLUSIONS

A favorable built environment may contribute to health-related physical fitness and physical activity of adolescents and should be considered in future interventions and health promotion strategies.

Seasonal variation in physical activity and sedentary time in different European regions. The HELENA study

This report aims (1) to examine the association between seasonality and physical activity (PA) and sedentary time in European adolescents and (2) to investigate whether this association was influenced by geographical location (Central-North versus South of Europe), which implies more or less extreme weather and daylight hours. Valid data on PA, sedentary time and seasonality were obtained in 2173 adolescents (1175 females; 12.5-17.5 years) included in this study. Physical activity and sedentary time were measured by accelerometers. ANCOVA was conducted to analyse the differences in PA and sedentary time across seasons. Results showed that girls had lower levels of moderate to vigorous PA (MVPA) and average PA, and spent more time in sedentary activities in winter compared with spring (all P < 0.05). Stratified analyses showed differences in PA and sedentary time between winter and spring in European girls from Central-North of Europe (P < 0.05 for sedentary time). There were no differences between PA and sedentary time across seasonality in boys. In conclusion, winter is related with less time spent in MVPA, lower average PA and higher time spent in sedentary activities in European adolescent girls, compared with spring. These differences seem to mainly occur in Central-North Europe.

[Assessment of cardiorespiratory functional fitness in children: walking tests and running tests]

Cardiorespiratory fitness (CF) is an important factor in treating various paediatric pathologies. As a consequence, assessing CF has widespread clinical application as part of paediatric intervention programs. Several methods have been developed for the purpose of measuring CF. The aim of this review is to describe and evaluate test procedures that are currently in use. Direct measurement in a laboratory setting has the advantage of high validity and reliability. The disadvantage, however, is that laboratory assessment of CF requires trained personnel, takes more time than field tests, and necessitates costly equipment. Conversely, field tests are easier to administer, require less time and utilise less expensive equipment. The choice of the test mode must take into account the age and health of the subject. The availability of a variety of tests makes it possible for the clinician/researcher to choose the most assessment that is most appropriate for the target population, study objectives, and available resources according to the research methods of the study.

Genetic and molecular insights into the role of PROX1 in glucose metabolism

Genome-wide association studies have shown that the rs340874 single nucleotide polymorphism (SNP) in PROX1 is a genetic susceptibility factor for type 2 diabetes. We conducted genetic and molecular studies to better understand the role of PROX1 in type 2 diabetes. We assessed the impact of the whole common genetic variability of PROX1 (80 SNPs) on type 2 diabetes-related biochemical traits in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study (n = 1,155). Three SNPs (rs340838, rs340837, and rs340836) were significantly associated with fasting plasma insulin levels (P ≤ 0.00295). We evaluated the impact of nine PROX1 SNPs (the three insulin-associated SNPs plus six SNPs in strong linkage disequilibrium) on luciferase reporter gene expression. The insulin-lowering alleles of rs340874, rs340873, and rs340835 were associated with lower luciferase activity in MIN6 and HepG2 cells (except for rs340874, which was in HepG2 cells only). Electrophoretic mobility shift assays indicated that specific nuclear protein bindings occur at the three SNPs in HepG2 cells, with allele-binding differences for rs340874. We also showed that the knockdown of Prox1 expression by small interfering RNAs in INS-1E cells resulted in a 1.7-fold reduction in glucose-stimulated insulin secretion. All together, we propose that reduced expression of PROX1 by cis-regulatory variants results in altered β-cell insulin secretion and thereby confers susceptibility to type 2 diabetes.

Nutritional and pubertal status influences accuracy of self-reported weight and height in adolescents: the HELENA Study

BACKGROUND AND AIMS

The aim of this study was to assess factors that have an effect on the accuracy of self-reported weight and height in adolescents.

METHODS

Weight and height of 3,865 European adolescents aged 12.5 to 17.5 years were self-reported via specific questionnaire. Then real weight and height were measured using accurate equipment and standardized protocols. Differences (D) between self-reported and measured weight and height were calculated, and factors that could have influenced the accuracy of self-reported weight and height were assessed. Data were analyzed using ANOVA, Student's t test and multivariate regression.

RESULTS

Adolescents underestimated their weight (D = -0.81 kg; n = 2,968) and overestimated their height (D = +0.74 cm; n = 3,308). Obese girls underestimated their weight (D = -4.70 kg) and overestimated their height (D = +0.22 cm) to a greater extent (p < 0.05) than obese boys (D = -3.13 kg and +0.14 cm for weight and height, respectively). Underestimation of weight (D = -1.25 kg) and overestimation of height (D = +0.15 cm) were only significant for girls who had finished puberty (Tanner stage 5). Socioeconomic status, nutritional knowledge, physical fitness, physical activity level, food choice and preference, and healthy eating behaviour had no significant influence on the accuracy of self-reported weight and height.

CONCLUSION

Our data confirms that self-reports of weight and height made by adolescents are inaccurate and demonstrate that inaccuracy is strongly influenced by nutritional status, pubertal status and gender.