Longitudinal relationship between screen time, cardiorespiratory fitness, and waist circumference of children and adolescents: a 3-year cohort study.

PURPOSE: The aim of this study was to examine the interaction between screen time and cardiorespiratory fitness (CRF) in their longitudinal association with waist circumference (WC) during a follow-up of 3 years from childhood to adolescence. METHODS: Observational 3-year longitudinal study with 401 students (224 females), seven to 15 years of age at baseline. The CRF was evaluated by estimating peak oxygen uptake (VO2peak) from an indirect field-based test and body mass index. Screen time was assessed using self-reported questionnaires. Moderation analyses were tested using a multiple linear regression model with adjustments for sex, age, puberty stage, and ethnicity. RESULTS: A statistically significant interaction term was observed (B = -0.0003; 95% CI: -0.007; -0.0001). Since screen time was contextualized as the independent variable, the results show that relationship between screen time and WC varies across different CRF levels. CONCLUSION: The findings suggest that higher CRF can attenuate the harmful association that increased sedentary behavior might have on abdominal adiposity.

Dose-response associations of Monitor-Independent Movement Summary with health-related fitness in youth.

The purpose of this study was to determine the dose-response associations between Monitor-Independent Movement Summary (MIMS) units and health-related fitness in youth. The sample comprised US children and adolescents who participated in the 2012 National Youth Fitness Survey (NNYFS; N = 1158, 48.9% female). Health-related fitness domains were assessed using tests of cardiorespiratory endurance (timed maximal and graded treadmill tests), muscular strength (modified pull-up and grip tests), and muscular endurance (plank test). Movement data were collected using wrist-worn ActiGraph accelerometers with raw data processed using MIMS and the calculated metrics of average MIMS/day, Peak 60-min MIMS, and Peak 30-min MIMS. Weighted regression models examined linear associations between MIMS metrics and fitness test scores. Nonlinear associations were examined using weighted spline models with knots placed at the 10th, 50th, and 90th percentiles. Models were adjusted for covariates and fit was examined using the coefficient of determination (R2 ). The strongest adjusted linear relationships included a positive association between MIMS/day (per every 1000 units) and maximal endurance times (b = 5.5 s, p < 0.001) and between Peak 60-min MIMS (per every 10 units) and estimated aerobic capacity (b = 1.7 mL/kg/min, p < 0.001), modified pull-ups (b = 0.7 reps, p < 0.001), and plank test scores (b = 5.0 s, p < 0.001). Linear spline models had slightly higher R2 values (R2 range = 16.9%-74.8%) compared to linear models (R2 range = 15.0%-74.5%). The relationship between MIMS metrics and fitness test scores was best modeled as piecewise linear functions. Although all MIMS metrics associated with cardiorespiratory endurance, Peak 60-min MIMS showed stronger associations with tests of muscular strength and endurance.

The stability of cardiometabolic risk factors clustering in children and adolescents: a 2-year longitudinal study.

Objective: The present study aims to verify the odds of remaining with the clustering of 3 or more, 4 or more, and 5 or more risk factors across a 2-year time span. Methods: Observational longitudinal study that included 358 children and adolescents (10.96 ± 2.28 years of age at baseline). Cardiorespiratory fitness, glucose, systolic blood pressure, total cholesterol/high-density lipoprotein cholesterol ratio, triglycerides, and waist circumference were assessed. The number of children in whom the risk factors were not independently distributed was analyzed. Odds ratios of presenting n risk factors clustered at follow-up according to the number of risk factors observed at baseline were calculated. Results: More participants than expected were found presenting clustering of 4 or more and 5 or more risk factors at both baseline (11.7% and 5.6%, respectively) and follow-up (9.5% and 5.6%, respectively). The odds ratios calculated demonstrated that the odds of presenting the same number of risk factors clustered or more at follow-up increased according to the number of risk factors clustered at baseline. Conclusion: The higher the number of risk factors a child had at baseline, the higher the odds of presenting the same number of risk factors or more after two years of follow-up. Supplementary Information: The online version contains supplementary material available at 10.1007/s40200-022-01174-1.

The genetic predisposition increases the chances of schoolchildren maintaining higher adiposity levels after three years.

BACKGROUND: The behavior of anthropometrics and the relationship with genetic factors through a long-term perspective should be better explored. This study aims to verify the odds of maintaining the nutritional status classification after three years, according to the rs9939609 polymorphism (FTO gene). METHODS: It was a retrospective longitudinal study with 355 schoolchildren (7-17 years). Body mass index, body-fat percentage (BF%), and waist circumference (WC) were measured at baseline and follow-up. The FTO gene was evaluated from blood collection and genotyping performed by real-time polymerase chain reaction. Odds ratios and 95% confidence intervals were calculated. RESULTS: For those homozygous with the A allele, the odds of being at less favorable classification at follow-up were 2.29 (1.24; 4.22) and 4.05 (2.08; 7.86) times higher than expected for BF% and WC, respectively, whereas the odds of being in the more favorable classification at follow-up were 0.34 (0.12; 0.93) and 0.11 (0.01; 0.78) for BF% and WC, respectively. The odds of being at less favorable classification were higher for AA carriers with less favorable classification at baseline for BF% and WC compared to AT and TT carriers. CONCLUSIONS: Schoolchildren with a genetic predisposition to obesity and unfavorable anthropometric profile at baseline had more chances of maintaining their nutritional status after three years of follow-up.

Identifying the ideal "body shape" associated with athletic performance using three dimensional (height, body mass and waist) allometry.

The purpose of the current study was to identify the most appropriate "body shape" associated with six athletic performance (AP) tests, using three-dimensional allometry (height (HT), body mass (M), and waist circumference (WC)), in a sample of Brazilian children and adolescents. The sample consisted of 11018 Brazilian children/adolescents (5147 boys) aged 7-17 years. The 6 AP tests were, a 20 m sprint test, an agility test, a 6/9 minute walk/run endurance test, an upper body strength test, an abdominal muscular endurance test, and a lower limb strength test. The "three-dimensional" allometric model was, AP= a⋅ Mk1⋅ HTk2⋅ WCk3. Results indicated that two of the three body-size dimensions (HT and WC) were consistently associated with all six athletic performance tests. These were a positive HT exponent/term together with a negative WC exponent/term, confirming that being taller benefited all six performance tests but excess WC was always detrimental. The contribution of M depended on whether the athletic performance required the children/adolescent to perform the exercise/test in a "weight-baring" protocol, i.e. having to perform the test carrying their own body weight or not. In conclusion, three-dimensional allometry provides new insights into what constitutes the "ideal" athletic shape associated with children/adolescents.

Body fat percentage, cardiorespiratory fitness and arterial blood pressure in children and adolescents: a longitudinal analysis.

BACKGROUND: A better understanding of how cardiorespiratory fitness (CRF) and adiposity interact to associate with arterial blood pressure over time remains inconclusive. Thus, the aim of the present study was to examine whether changes in CRF moderates the association between body fat percentage (BF%) and arterial blood pressure in children and adolescents. METHODS: This is an observational longitudinal study with 407 children and adolescents aged 8-17 years followed-up for three years from a city in Southern Brazil. Participants were evaluated in 2011 and 2014. CRF was measured by validated field-based tests following the Projeto Esporte Brazil protocols and peak oxygen uptake (VO2peak) was estimated. BF% was determined by the measures of tricipital and subscapular skinfolds using equations according to sex. Systolic and diastolic blood pressure (SBP, DBP) were measured with a sphygmomanometer according to standard procedures. Moderation analyses included multiple linear regression models adjusted for sex, age, pubertal status, height, socioeconomic level, skin color, and the arterial blood pressure variable itself at baseline. RESULTS: It was observed a significant inverse association between VO2peak at baseline with SBP (ß = - 0.646 CI95% = - 0.976 - 0.316) and DBP (ß = - 0.649 CI95% = - 0.923 - 0.375) at follow-up and a positive association between BF% at baseline with SBP (ß = 0.274; CI95% = 0.094 0.455) and DBP (ß = 0.301; CI95% = 0.150 0.453) at follow-up. In addition, results indicated a significant interaction term between changes in VO2peak and BF% at baseline with both SBP (p = 0.034) and DBP at follow-up (p = 0.011), indicating that an increase of at least 0.35 mL/kg/min and 1.78 mL/kg/min in VO2peak attenuated the positive relationship between BF% with SBP and DBP. CONCLUSION: CRF moderates the relationship between BF% and SBP and DBP in children and adolescents.

What is the role of cardiorespiratory fitness and sedentary behavior in relationship between the genetic predisposition to obesity and cardiometabolic risk score?

BACKGROUND: Genetic factors along with inadequate lifestyle habits are associated with the development of cardiometabolic alterations. Thus, the present study aimed to examine the role of sedentary behavior on the relationship between rs9939609 polymorphism (fat mass and obesity-associated gene-FTO) and cardiometabolic risk score according to cardiorespiratory fitness (CRF) levels in children and adolescents. METHODS: A cross-sectional study with 1215 children and adolescents (692 girls), aged between 6 and 17 years. Screen time as a marker of sedentary behavior was evaluated through a self-reported questionnaire and CRF was estimated using the 6-min walking and running test. The genotyping of the FTO rs9939609 polymorphism was performed using a real-time polymerase chain reaction. Clustered cardiometabolic risk score (cMetS) was calculated by summing z-scores of total cholesterol/high-density lipoprotein cholesterol ratio, triglycerides, glucose, systolic blood pressure, and waist circumference, and dividing it by five. Moderation analyses were tested using multiple linear regression models. RESULTS: The coefficient of the interaction term of FTO (rs9939609) and screen time indicated that screen time was a significant moderator on the relationship between FTO rs9939609 polymorphism and cMetS (p = 0.047) in children and adolescents classified with low CRF (ß = 0.001; 95% CI = 0.001; 0.002). It was observed a significant association between genotype risk (AA) of FTO polymorphism and cMetS, in participants that spent more than 378 min a day in front of screen-based devices (ß = 0.203; 95% CI = 0.000; 0.405). No interaction term was found for those with high CRF. CONCLUSIONS: High sedentary behavior seems to influence the relationship between genetic predisposition to obesity and cardiometabolic risk factors in children and adolescents with low CRF.

Clustering of cardiometabolic risk factors and the continuous cardiometabolic risk score in children from Southern Brazil: a cross-sectional study.

PURPOSE: The present study aimed to verify the clustering of cardiometabolic risk factors for cardiovascular diseases (CVD) and its relationship with the continuous cardiometabolic risk score (cMetS). METHODS: Cross-sectional study with 631 children aged 6 to 9 years. Cardiorespiratory fitness, glucose, systolic blood pressure, total cholesterol/high-density lipoprotein cholesterol ratio, triglycerides, and waist circumference were assessed. The number of children in whom the risk factors were not independently distributed was analyzed. Z-scores were computed for each risk factor to calculate the cMetS. RESULTS: There was a high proportion of children with clustering of risk factors for CVD. The clustering of risk factors was apparent in 11.3% of the children for four or more risk factors, and 21.9% had three or more risk factors. The cMetS showed a linear relationship with the increase in the number of risk factors. A cMetS value higher than 0.91 indicated clustering of cardiometabolic risk factors amongst children. CONCLUSION: The use of clustering of cardiometabolic risk factors identified a high proportion of children with the presence of relevant cardiometabolic alterations. A cMetS value higher than 0.91 (relative to an international standard) indicated higher clustering of cardiometabolic risk factors amongst children. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40200-021-00845-9.

Cardiorespiratory Fitness and Muscular Strength Moderates the Relationship between FNDC5 Polymorphism and Adiposity in Children and Adolescents.

The human locus FNDC5 rs16835198 contributes positively to anthropometric phenotypes in children and adolescents. However, the role of specific components of physical fitness in this relationship is not known. The present study aimed to verify the moderator role of cardiorespiratory fitness (CRF) and muscular strength in the relationship between rs16835198 polymorphism FNDC5 and adiposity in children and adolescents. This cross-sectional study was carried out by genotyping the rs16835198 FNDC5 polymorphism in 1701 children and adolescents (mean age 11.73 ± 2.75 years). Obesity was assessed using waist circumference and body mass index (BMI) z-scores. To evaluate CRF and muscular strength, the 6 min run/walk test and lower limb strength (LLS) were used. Linear regression models were applied, and all analyses were adjusted for age, sex, skin color, living area, and school type. A significant interaction term for CRF (p = 0.038) and LLS (p = 0.040) × rs16835198 FNDC5 with WC was identified. Regarding BMI, a significant interaction term for CRF (p = 0.007) and LLS (p = 0.044) × rs16835198 FNDC5 was observed. Moreover, medium and high CRF and LLS levels protected against higher WC and BMI. In conclusion, adiposity levels of children and adolescents with a genetic predisposition to obesity might be modified by improving CRF and muscular strength.

FTO gene polymorphism and longitudinal changes in nutritional/obesity status in children and adolescents: Schoolchildren's health cohort study.

The fat mass and obesity-associated gene (FTO) has been extensively reported in the literature related to nutritional status, but there has been limited description of the genetic contribution to obesity risk during childhood and adolescence, especially in Latin Americans. This study aims to associate the rs9939609 polymorphism, of the FTO gene, with changes in nutritional status in Brazilian schoolchildren followed for 3 years. A longitudinal study was conducted with 355 schoolchildren, aged 7-15 years in 2011/2012 and subsequently re-evaluated in 2014/2015. Nutritional (obesity) status was classified by identifying those exceeding recommended thresholds for waist circumference (WC), waist-to-height ratio (WHtR), body mass index (BMI), and body fat percentage (BF%). The rs9939609 polymorphism was genotyped by a real-time polymerase chain reaction. Relative risk (RR with 95% confidence interval) of obesity status by FTO gene polymorphism was calculated by Poisson regression. The risk group was determined for genotypes with the allele A polymorphism, and regression models were adjusted for age, sex, height, ethnicity, and geographical location. Considering the longitudinal changes in status over the 3-year follow-up, the RR of developing a WC exceeding the threshold recommended (WC >75th age and sex-standardized percentile), or remaining with this condition, was higher in children with AT/AA genotype. For WC, the RR was 1.66 (1.07; 2.58) in crude analysis and 1.17 (1.01; 1.35) following adjustment for age (years), gender, ethnicity, and geographical location. The comparative risk of abdominal obesity, assessed by WHtR (not recommended threshold ≥0.50), was 53% and 8%, respectively, higher in AT/AA compared to TT genotype.Conclusion: This is one of the first longitudinal investigations to show a significant association between the A allele of the rs9939609 polymorphism and individuals with higher than recommended WC and WHtR measures in Brazilian children and adolescents. What is known: • The FTO has an effect on increases in body mass index (BMI) among children and adolescents. • It established the association between FTO and overweight/obesity in Caucasians. What is new: • The presence of the risk allele of rs9939609 (FTO gene) polymorphism is associated with increased abdominal fat in Brazilian schoolchildren. • Was detected an association between FTO gene polymorphism (rs9939609) with WC in follow-up cohort and changes in WC and WHtR follow-up over 3 years, during childhood and adolescence growth.

Low levels of cardiorespiratory fitness and abdominal resistance are associated with metabolic risk in schoolchildren.

Background Low levels of physical fitness are associated with metabolic disorders in adults. However, this relationship has been little explored in children and adolescents. The aim of the present study was to investigate whether there is an association between physical fitness related to health and the presence of metabolic risk in schoolchildren. Methods The sample for this cross-sectional study was composed of 1251 schoolchildren of both genders between 7 and 17 years of age. Three indicators of physical fitness related to health were evaluated: cardiorespiratory fitness (CRF), flexibility and abdominal resistance. The continuous metabolic syndrome score (cMetS) was calculated by using the sum of the Z scores of the following indicators: body mass index (BMI), systolic blood pressure, glucose, total cholesterol, high- and low-density lipoprotein cholesterol (HDL-c and LDL-c) and triglycerides. Subsequently, the cMetS was dichotomized, considering the presence or absence of metabolic risk. The data were analyzed using prevalence ratio (PR) values and 95% confidence intervals (CI), using Poisson regression. Results A higher prevalence of metabolic risk was found among students with low levels of CRF (PR: 1.48; CI: 1.10-1.98) and abdominal resistance (PR: 1.45; CI: 1.08-1.95). No association with flexibility was found. Conclusions Low levels of CRF and abdominal resistance are associated with the presence of metabolic risk in schoolchildren.