Oscar L. Veiga

Interplay Between Weight Loss and Gut Microbiota Composition in Overweight Adolescents

The aim of this study was to determine the influence of an obesity treatment program on the gut microbiota and body weight of overweight adolescents. Thirty‐six adolescents (13–15 years), classified as overweight according to the International Obesity Task Force BMI criteria, were submitted to a calorie‐restricted diet (10–40%) and increased physical activity (15–23 kcal/kg body weight/week) program over 10 weeks. Gut bacterial groups were analyzed by quantitative real‐time PCR before and after the intervention. A group of subjects (n = 23) experienced >4.0 kg weight loss and showed significant BMI (P = 0.030) and BMI z‐score (P = 0.035) reductions after the intervention, while the other group (n = 13) showed <2.0 kg weight loss. No significant differences in dietary intake were found between both groups. In the whole adolescent population, the intervention led to increased Bacteroides fragilis group (P = 0.001) and Lactobacillus group (P = 0.030) counts, and to decreased Clostridium coccoides group (P = 0.028), Bifidobacterium longum (P = 0.031), and Bifidobacterium adolescentis (P = 0.044) counts. In the high weight–loss group, B. fragilis group and Lactobacillus group counts also increased (P = 0.001 and P = 0.007, respectively), whereas C. coccoides group and B. longum counts decreased (P = 0.001 and P = 0.044, respectively) after the intervention. Total bacteria, B. fragilis group and Clostridium leptum group, and Bifidobacterium catenulatum group counts were significantly higher (P < 0.001–0.036) while levels of C. coccoides group, Lactobacillus group, Bifidobacterium, Bifidobacterium breve, and Bifidobacterium bifidum were significantly lower (P < 0.001–0.008) in the high weight–loss group than in the low weight–loss group before and after the intervention. These findings indicate that calorie restriction and physical activity have an impact on gut microbiota composition related to body weight loss, which also seem to be influenced by the individuals microbiota.

Shifts in clostridia, bacteroides and immunoglobulin-coating fecal bacteria associated with weight loss in obese adolescents

Objective:To evaluate the effects of a multidisciplinary obesity treatment programme on fecal microbiota composition and immunoglobulin-coating bacteria in overweight and obese adolescents and their relationship to weight loss.Design:Longitudinal intervention study based on both a calorie-restricted diet (calorie reduction=10–40%) and increased physical activity (calorie expenditure=15–23 kcal/kg body weight per week) for 10 weeks.Participants:Thirty-nine overweight and obese adolescents (BMI mean 33.1 range 23.7–50.4; age mean 14.8 range, 13.0–16.0).Measurements:BMI, BMI z-scores and plasma biochemical parameters were measured before and after the intervention. Fecal microbiota was analyzed by fluorescent in situ hybridization. Immunoglobulin-coating bacteria were detected using fluorescent-labelled F(ab′)2 antihuman IgA, IgG and IgM.Results:Reductions in Clostridium histolyticum and E. rectale-C. coccoides proportions significantly correlated with weight and BMI z-score reductions in the whole adolescent population. Proportions of C. histolyticum, C. lituseburense and E. rectale-C. coccoides dropped significantly whereas those of the Bacteroides-Prevotella group increased after the intervention in those adolescents who lost more than 4 kg. Total fecal energy was almost significantly reduced in the same group of adolescents but not in the group that lost less than 2.5 kg. IgA-coating bacterial proportions also decreased significantly in participants who lost more than 6 kg after the intervention, paralleled to reductions in C. histolyticum and E. rectale-C. coccoides populations. E. rectale-C. coccoides proportions also correlated with weight loss and BMI z-score reduction in participants whose weight loss exceeded 4 kg.Conclusions:Specific gut bacteria and an associated IgA response were related to body weight changes in adolescents under lifestyle intervention. These results suggest interactions between diet, gut microbiota and host metabolism and immunity in obesity.

Sedentarismo, adiposidad y factores de riesgo cardiovascular en adolescentes. Estudio AFINOS

Introduccion y objetivos Examinar las asociaciones entre sedentarismo medido de forma objetiva y los factores de riesgo cardiovascular (RC). Un objetivo secundario fue evaluar el grado de asociacion entre adiposidad general y abdominal con factores de RC. Metodos Doscientos diez adolescentes, de 13-17 anos, participaron en este estudio transversal. Se midio la suma de seis pliegues (sum6), perimetro de cintura (PC), presion arterial sistolica (PAS) y diastolica (PAD), glucosa, colesterol total (CT), trigliceridos (TG), colesterol de las lipoproteinas de alta (cHDL) y baja densidad (cLDL) y apolipoproteinas A-1 y B-100. Se calculo un indice de RC (IRC) usando presion arterial media (PAM), TG, cHDL y glucosa. El sedentarismo se valoro con acelerometro durante 7 dias. Se dividio a los participantes en terciles de sedentarismo y en niveles de baja-alta adiposidad general (sum6) y abdominal (PC). Resultados Los adolescentes con niveles altos de sedentarismo tuvieron valores menos favorables de PAS, TG, glucosa e IRC. Los adolescentes con mayor nivel de adiposidad general mostraron diferencias significativas en cinco de once factores analizados (PAD, cLDL, CT, apolipoproteina B-100 e IRC), mientras que los adolescentes con mas adiposidad abdominal tuvieron diferencias en ocho factores (PAS, PAM, cHDL, cLDL, TG, CT, apolipoproteina B-100 e IRC). Los adolescentes con mayor adiposidad general y abdominal y con niveles altos de sedentarismo mostraron un IRC menos favorable. Conclusiones El sedentarismo esta asociado con factores de RC en adolescentes, especialmente en los adolescentes obesos. La adiposidad abdominal parece ser mas importante en el desarrollo de factores de RC que la adiposidad general.

Recommended levels of physical activity to avoid an excess of body fat in European adolescents: the HELENA Study.

BACKGROUND It is unclear how much physical activity is necessary to prevent obesity during adolescence. PURPOSE The purpose of this study was to examine whether the current physical activity guidelines for youth are associated with a lower risk of excess of body fat in European adolescents. METHODS A sample of 2094 adolescents from the HELENA cross-sectional study was selected. Levels of moderate, vigorous, and moderate to vigorous physical activity (MVPA) were assessed using accelerometers. BMI and percentage of body fat (skinfolds) were calculated and used to categorize the adolescents as normal-weight/normal-fat, overweight/overfat, and obese. Data were collected during 2006-2007. Receiver operating characteristic (ROC) analysis, performed in 2009, was used to determine thresholds that best discriminate between weight and body fat categories. RESULTS ROC analysis showed that >/=18 minutes/day in vigorous physical activity and >/=55 minutes/day in MVPA significantly discriminated between normal-weight and overweight+obesity categories. Moreover, >/=9 minutes/day of vigorous physical activity and >/=49 minutes/day of MVPA discriminated between normal-fat and overfat/obese adolescents. Adolescents who did not meet the current physical activity guidelines for youth of 60 minutes/day in MVPA increased the risk of having overweight+obesity (OR=1.24, 95% CI=1.01, 1.534) and overfat+obesity (OR=1.79, 95% CI=1.33, 2.42). ORs increased when adolescents did not meet the guidelines of at least 15 minutes/day in vigorous physical activity. CONCLUSIONS Current physical activity guidelines seem to be appropriate to prevent excess of body fat in European adolescents. However, participation in vigorous physical activity might have additional importance in preventing obesity.

Fiabilidad y validez del cuestionario de actividad física PAQ-A en adolescentes españoles

Reliability and Validity of the PAQ-A Questionnaire to Assess Physical Activity in Spanish Adolescents Background: Questionnaires are feasible instruments to assess physical activity (PA) in large samples. The aim of the current study was to evaluate the reliability and validity of the PAQ-A questionnaire in Spanish adolescents using the measurement of PA by accelerometer as criterion. Methods: In a sample of 82 adolescents, aged 12 to 17 years, 1week PAQ-A test-retest was administered. Reliability was analyzed by the Intraclass Correlation Coefficient (ICC) and the internal consistency by the Cronbach’s α Coefficient. Two hundred thirty-two adolescents, aged 13-17 years, completed the PAQ-A and wore the ActiGraph GT1M accelerometer during 7-days. The PAQ-A was compared against total PA and moderate to vigorous PA (MVPA) obtained by the accelerometer. Results: Test-retest reliability showed ICC = 0.71 for the final score of PAQ-A. Internal consistency was α = 0.65 in the first selfreport, α = 0.67 in the retest in 82 adolescents sample, and α = 0.74 in the 232 adolescents sample. The PAQ-A was moderately correlated with total PA (rho = 0.39) and MVPA (rho= 0.34) assessed by the accelerometer. The PAQ-A obtained significantly moderate correlations in boys but not in girls against the accelerometer. Conclusions: The PAQ-A questionnaire shows an adequate reliability and a reasonable validity for assessing PA in Spanish adolescents.

Physical activity and cognition in adolescents: A systematic review

OBJECTIVES The purpose of this report is to perform a systematic review of the evidence on the associations between physical activity and cognition by differentiating between academic and cognitive performance measures. Second-generation questions regarding potential mediators or moderators (i.e., sex, age and psychological variables) of this relationship were also examined. DESIGN Systematic review. METHODS Studies were identified from searches in PubMed, Sportdiscus and ERIC databases from 2000 through 2013. The search process was carried out by two independent researchers. RESULTS A total of 20 articles met the inclusion criteria, 2 of them analyzed both cognitive and academic performance in relation to physical activity. Four articles (18%) found no association between physical activity and academic performance, 11 (50%) found positive association and one showed negative association (5%). Five articles (23%) found positive association between physical activity and cognitive performance and one showed negative association (5%). The findings of these studies show that cognitive performance is associated with vigorous physical activity and that academic performance is related to general physical activity, but mainly in girls. Results of the review also indicate that type of activity and some psychological factors (i.e., self-esteem, depression) could mediate the association between physical activity and academic performance. CONCLUSIONS Results of the review support that physical activity is associated with cognition, but more research is needed to clarify the role of sex, intensity and type of physical activity and some psychological variables of this association.

Sedentary Behavior, Adiposity, and Cardiovascular Risk Factors in Adolescents. The AFINOS Study

INTRODUCTION AND OBJECTIVES To investigate the association between objective measures of sedentary behavior and cardiovascular risk factors (CRFs) in adolescents. A secondary aim was to evaluate the degree of association between overall and abdominal adiposity and CRFs. METHODS This cross-sectional study involved 210 adolescents aged 13-17 years. Measurements were made of the sum of the skinfold thicknesses at six locations (sum6), waist circumference (WC), systolic (SBP) and diastolic blood pressure (DBP), glucose, total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and apolipoproteins A-1 and B-100. A CRF score was calculated from the mean arterial pressure (MAP) and TG, HDL-C and glucose levels. Sedentary behavior was assessed over 7 days using an accelerometer. Participants were divided into tertiles according to sedentary behavior and into low and high levels of overall (sum6) and abdominal (WC) adiposity. RESULTS Adolescents with a high level of sedentary behavior had less favorable SBP, TG and glucose levels and CRF scores. Adolescents with a high level of overall adiposity demonstrated significant differences in five of the 11 variables analyzed (i.e. DBP, LDL-C, TC, apolipoprotein B-100 and CRF score), while adolescents with a high level of abdominal adiposity had differences in eight (i.e. SBP, MAP, HDL-C, LDL-C, TG, TC, apolipoprotein B-100 and CRF score). Adolescents with high levels of both overall and abdominal adiposity and sedentary behavior had the least favorable CRF scores. CONCLUSIONS Sedentary behavior was associated with CRFs in adolescents, especially in obese adolescents. Abdominal adiposity seemed to play a more significant role in the development of CRFs than overall adiposity.

Recommended levels and intensities of physical activity to avoid low‐cardiorespiratory fitness in European adolescents: The HELENA study

The purpose of this study was to determine the sex‐specific physical activity (PA) intensity thresholds that best discriminate between unhealthy/healthy cardiorespiratory fitness (CRF).

Active commuting to school and cognitive performance in adolescents: the AVENA study.

OBJECTIVE To examine the associations between active commuting to school and cognitive performance in adolescents. DESIGN Cross-sectional study. SETTING Five cities (Granada, Madrid, Murcia, Santander, and Zaragoza) in Spain. PARTICIPANTS A total of 1700 adolescents (892 girls) aged 13 to 18.5 years. MAIN EXPOSURES Mode and duration of transportation to school and participation in extracurricular physical activity were self-reported. MAIN OUTCOME MEASURES Cognitive performance (verbal, numeric, and reasoning abilities and an overall score) was measured by the Spanish version of the SRA Test of Educational Ability. RESULTS Active commuting to school was associated with better cognitive performance (all P < .05) in girls but not in boys, independent of potential confounders including participation in extracurricular physical activity. In addition, adolescent girls who spent more than 15 minutes actively commuting to school had better scores in 3 of the 4 cognitive performance variables (all P < .05) than those who spent less time actively commuting to school (≤15 minutes) as well as better scores in all of the cognitive performance variables (all P < .001) than girls inactively commuting. CONCLUSION Active commuting to school and its duration may positively influence cognitive performance in adolescent girls.

Excessive sedentary time and low cardiorespiratory fitness in European adolescents: the HELENA study

Background The aims of this study were to examine what amount of sedentary time is associated with low cardiorespiratory fitness (CRF) in adolescents and whether this association is independent of physical activity. Methods The study comprised 1808 adolescents aged 12.5–17.5 years from 10 European cities. Sedentary time and moderate-to-vigorous physical activity (MVPA) were measured by accelerometer. CRF was assessed by the 20 m shuttle-run test. Adolescents were divided into two groups (high/low) according to FITNESSGRAM guidelines. Receiver-operating characteristic (ROC) analysis was used to determine thresholds that best discriminate between high and low CRF in adolescents. Results Adolescent girls had more sedentary time than boys (p<0.001). ROC analysis showed that girls spending ≥69% of waking time in sedentary activities had low CRF, but no significant threshold discriminated between high and low CRF in boys. Adolescent girls who exceeded this threshold had lower levels of CRF (p≤0.001) and were more likely to have a low CRF (OR 1.68, 95% CI 1.22 to 2.31) independent of centre, age and body mass index. The negative influence of excessive sedentary time on CRF remained significant (p=0.045) in adolescent girls who did not meet the physical activity guidelines (<60 min/day in MVPA) but was abolished (p>0.05) in those who met the recommendation (≥60 min/day in MVPA). Conclusion Excessive sedentary time is associated with low CRF in adolescent girls but not in boys. However, this adverse effect might be attenuated if adolescent girls meet the current physical activity guidelines.