Does Weight Status Impact Metabolic Health in Adolescents When Controlling for Physical Fitness?

Purpose: To determines whether adolescents who are fit with overweight/obesity are similar in their metabolic profile to adolescents who are fit and normal weight. Methods: Adolescents participated in 3 sessions: (1) resting vitals and anthropometrics; (2) maximal aerobic treadmill test () to determine physical fitness; and (3) dual-energy x-ray absorptiometry and fasting laboratory draw for analysis of insulin, glucose, high-density lipoprotein, triglycerides, and C-reactive protein. Results: Of the 30 fit adolescents who are normal weight and 16 adolescents who are fit and overweight/obese (OW/OB), metabolic syndrome was apparent in 1 adolescent who are normal weight and 4 adolescents who are OW/OB. Metabolic syndrome severity was positively associated with body mass index, waist circumference, total body fat, insulin resistance, and C-reactive protein but inversely associated with peak relative, but not lean . Conclusions: Despite good physical fitness, adolescents who are OW/OB demonstrated greater metabolic syndrome than adolescents who are normal weight. Future intervention research is necessary to explore the relation between physical fitness and metabolic syndrome

High-sensitivity C-reactive protein is a predictive factor of adiposity in children : results of the Identification and prevention of Dietary- and lifestyle-induced health Effects in Children and InfantS (IDEFICS) study

Background-Whereas cross-sectional studies have shown that obesity is associated with increased C-reactive protein (CRP) levels in children, little is known about the impact of low-grade inflammation on body mass changes during growth. Methods and Results-We assessed cross-sectionally and longitudinally the association of high-sensitivity (hs)-CRP levels with overweight/obesity and related cardiometabolic risk factors in the Identification and prevention of Dietary-and lifestyle-induced health Effects in Children and InfantS (IDEFICS) cohort. 16 224 children from 8 European countries (2 to 9 years) were recruited during the baseline survey (T0). After the exclusion of 7187 children because of missing hs-CRP measurements and 2421 because of drug use during the previous week, the analysis was performed on 6616 children (Boys=3347; Girls=3269; age=6.3 +/- 1.7 years). Of them, 4110 were reexamined 2 years later (T1). Anthropometric variables, blood pressure, hs-CRP, blood lipids, glucose and insulin were measured. The population at T0 was divided into 3 categories, according to the baseline hs-CRP levels. Higher hs-CRP levels were associated with significantly higher prevalence of overweight/obesity, body mass index (BMI) z-score and central adiposity indices (P values all <0.0001), and with higher blood pressure and lower HDL-cholesterol levels. Over the 2-year follow-up, higher baseline hs-CRP levels were associated with a significant increase in BMI z-score (P<0.001) and significantly higher risk of incident overweight/obesity. Conclusions-Higher hs-CRP levels are associated to higher body mass and overweight/obesity risk in a large population of European children. Children with higher baseline levels of hs-CRP had a greater increase in BMI z-score and central adiposity over time and were at higher risk of developing overweight/obesity during growth

Volume, patterns, and types of sedentary behavior and cardio-metabolic health in children and adolescents: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Cardio-metabolic risk factors are becoming more prevalent in children and adolescents. A lack of moderate-to-vigorous intensity physical activity (MVPA) is an established determinant of cardio-metabolic risk factors in children and adolescents. Less is known about the relationship between sedentary behavior and cardio-metabolic health. Therefore, the objective was to examine the independent associations between volume, patterns, and types of sedentary behavior with cardio-metabolic risk factors among children and adolescents.</p> <p>Methods</p> <p>The results are based on 2527 children and adolescents (6-19 years old) from the 2003/04 and 2005/06 National Health and Nutrition Examination Surveys (NHANES). A cardio-metabolic risk score (CRS) was calculated based on age- and sex-adjusted waist circumference, systolic blood pressure, non-high-density lipoprotein cholesterol, and C-reactive protein values. Volume and patterns of sedentary behavior and moderate-to-vigorous physical activity (MVPA) were measured objectively using accelerometers. Types of sedentary behavior were measured by questionnaire. A series of logistic regression models were used to examine associations.</p> <p>Results</p> <p>Volume and patterns of sedentary behavior were not predictors of high CRS after adjusting for MVPA and other confounders (P > 0.1). For types of sedentary behavior, high TV use, but not high computer use, was a predictor of high CRS after adjustment for MVPA and other confounders. Children and adolescents who watched ≥4 hours per day of TV were 2.53 (95% confidence interval: 1.45-4.42) times more likely to have high CRS than those who watched <1 hour per day. MVPA predicted high CRS after adjusting for all sedentary behavior measures and other confounders. After adjustment for waist circumference, MVPA also predicted high non-obesity CRS; however, the same relationship was not seen with TV use.</p> <p>Conclusion</p> <p>No association was observed between overall volume and patterns of sedentary behavior with cardio-metabolic risk factors in this large sample of children and adolescents. Conversely, high TV use and low MVPA were independently associated with cardio-metabolic risk factors. However, the association between high TV use and clustered cardio-metabolic risk factors appears to be mediated or confounded by obesity. Thus, TV and MVPA appear to be two separate behaviors that need to be targeted with different interventions and policies.</p

Does the Fractionalization of Daily Physical Activity (Sporadic vs. Bouts) Impact Cardiometabolic Risk Factors in Children and Youth?

Children and youth accumulate their daily moderate-to-vigorous physical activity (MVPA) in bouts (i.e., ≥ 5 consecutive minutes) and in a sporadic manner (i.e., <5 consecutive minutes). The study objective was to determine, within children and youth, whether MVPA accumulated in bouts is more strongly associated with cardiometabolic risk factors than an equivalent volume of MVPA accumulated sporadically.Participants consisted of 2754 children and youth aged 6-19 years from the 2003-2006 National Health and Nutrition Examination Survey, a representative cross-sectional study. Bouts and sporadic MVPA were measured objectively over 7 days using Actigraph accelerometers. Thresholds of 5 and 10 consecutive minutes were used to differentiate between bouts and sporadic MVPA. A high cardiometabolic risk factor score (CRS) was created based on measures of waist circumference, non-high-density lipoprotein cholesterol, C-reactive protein, and systolic blood pressure. Associations were examined using logistic regression and controlled for covariates (sex, age, ethnicity, socioeconomic status, dietary fat and sodium, smoking, and accelerometry wear time).The odds of a high CRS decreased in a dose-response for both the sporadic and bout MVPA measures. Relative to quartile 1, the odds ratio (95% confidence interval) for a high CRS in quartile 4 was 0.25 (0.10-0.60) for sporadic MVPA, 0.17 (0.09-0.34) for ≥ 5 minute bouts of MVPA, and 0.19 (0.11-0.34) for ≥ 10 minute bouts of MVPA. The sporadic and bout MVPA measures had a similar ability to distinguish between participants with high and normal CRS. Relative to 0 minutes of MVPA, an equivalent number of minutes of sporadic MVPA and bouts of MVPA had an almost identical odds ratio for a high CRS. The findings were consistent for 5 and 10 minute bout thresholds.The relations between sporadic MVPA and bouts of MVPA with cardiometabolic risk factors were remarkably similar in children and youth

Understanding Relationships Between Early Life Toxic Stress, Childhood Socioeconomic Disadvantage, and Allostatic Load in Adolescence

Chronic disease prevalence among children and adolescents is rising, which is thought to result in part from elevations in allostatic load (AL). AL is the cumulative physiological dysregulation that results from exposure to biological, social and environmental stressors over time. Socioeconomic disparities in chronic disease and AL have been well-documented in adult populations, including links between childhood socioeconomic disadvantage (CSD) and AL, yet little is known as to whether CSD may begin to impact AL earlier in life. Differential exposure and vulnerability to stress among racial/ethnic minorities may increase risk for elevated AL among those experiencing CSD. Framed by the Life Course Perspective and the Allostatic Load Framework, the purpose of this dissertation was to determine the best measurement approach for AL, examine direct and indirect pathways between CSD and AL through several environmental and behavioral mediators, and determine whether these relationships varied across race/ethnicity. This was a cross-sectional, correlational study of 1900 adolescents (aged 12 to 18) from four waves (2003 to 2010) of the National Health and Nutrition Examination Survey (NHANES). We constructed latent variables for AL and CSD, based upon biologic and self-reported indicators. Smoking and lead exposure were measured with biomarkers, while nutrition, physical activity, and race/ethnicity were self-reported. Structural equation modeling (SEM) was used to examine relationships between latent construct variables and measured mediating variables across three race/ethnicity groups. The data best supported a unidimensional AL factor structure, with the highest factor loadings found for metabolic indicators. The only significant total effects pathway for CSD on AL was for Whites, indicating the model best explained AL variance for this group. There were small, positive direct effects pathways significant for African Americans (AAs) and Whites, indicating higher CSD predicted higher AL for those groups. A single indirect pathway between CSD and AL mediated by lead was significant for AA adolescents, though the reversed directionality suggests a need for a different measurement approach for cumulative lead exposure. These findings highlight the importance of exposure to CSD as a predictor for development of AL for adolescents, while also elucidating different mechanisms at play across different racial/ethnic populations

Light-intensity physical activity and cardiometabolic biomarkers in US adolescents

BackgroundThe minimal physical activity intensity that would confer health benefits among adolescents is unknown. The purpose of this study was to examine the associations of accelerometer-derived light-intensity (split into low and high) physical activity, and moderate- to vigorous-intensity physical activity with cardiometabolic biomarkers in a large population-based sample.MethodsThe study is based on 1,731 adolescents, aged 12&ndash;19 years from the 2003/04 and 2005/06 National Health and Nutrition Examination Survey. Low light-intensity activity (100&ndash;799 counts/min), high light-intensity activity (800 counts/min to &lt;4 METs) and moderate- to vigorous-intensity activity (&ge;4 METs, Freedson age-specific equation) were accelerometer-derived. Cardiometabolic biomarkers, including waist circumference, systolic blood pressure, diastolic blood pressure, HDL-cholesterol, and C-reactive protein were measured. Triglycerides, LDL- cholesterol, insulin, glucose, and homeostatic model assessments of &beta;-cell function (HOMA-%B) and insulin sensitivity (HOMA-%S) were also measured in a fasting sub-sample (n=807).ResultsAdjusted for confounders, each additional hour/day of low light-intensity activity was associated with 0.59 (95% CI: 1.18&ndash;0.01) mmHG lower diastolic blood pressure. Each additional hour/day of high light-intensity activity was associated with 1.67 (2.94&ndash;0.39) mmHG lower diastolic blood pressure and 0.04 (0.001&ndash;0.07) mmol/L higher HDL-cholesterol. Each additional hour/day of moderate- to vigorous-intensity activity was associated with 3.54 (5.73&ndash;1.35) mmHG lower systolic blood pressure, 5.49 (1.11&ndash;9.77)% lower waist circumference, 25.87 (6.08&ndash;49.34)% lower insulin, and 16.18 (4.92&ndash;28.53)% higher HOMA-%S.ConclusionsTime spent in low light-intensity physical activity and high light-intensity physical activity had some favorable associations with biomarkers. Consistent with current physical activity recommendations for adolescents, moderate- to vigorous-intensity activity had favorable associations with many cardiometabolic biomarkers. While increasing MVPA should still be a public health priority, further studies are needed to identify dose-response relationships for light-intensity activity thresholds to inform future recommendations and interventions for adolescents.</div

Childhood Obesity

This book aims to provide readers with a general as well as an advanced overview of the key trends in childhood obesity. Obesity is an illness that occurs due to a combination of genetic, environmental, psychosocial, metabolic and hormonal factors. The prevalence of obesity has shown a great rise both in adults and children in the last 30 years. It is known that one third of children who are obese in childhood and 80% of adolescents who are obese in their adolescent years continue to be obese later in life. Obesity is an important risk factor in serious illnesses such as heart disease, hyperlipidemia, hyperinsulinemia, hypertension and early atherosclerosis

Oxidative Status and Hypertension: An Examination of the Prospective Association Between Urinary F2-isoprostanes and Hypertension

Background: Hypertension is a pathological increase in blood pressure that affects nearly 30% of the U.S. population and is a primary modifiable risk factor for cardiovascular disease. Despite advancements in prevention and treatment, hypertension is still one of the most common conditions around the world, and for a majority of cases the causal mechanisms remain to be fully elucidated. A growing body of literature suggests that oxidative stress status may play an etiological role in many chronic conditions, including hypertension. Specifically, a systemic overabundance of reactive oxygen species may give rise to endothelial dysfunction, increased sodium and H2O retention, and alterations in sympathetic outflow, leading to an increase in blood pressure. Purpose: The main objective of this study is to investigate the prospective association between F2-isoprostanes, a validated biomarker of oxidative status, and development of hypertension in a large, multi-centered, multi-ethnic cohort of adults aged 40-69 at baseline. Methods: This is a secondary data analysis that utilized previously collected data from the Insulin Resistance Atherosclerosis Study. 844 participants were included in the analysis. Briefly, four urinary F2-isoprostane isomers (F2-IsoP1, F2-IsoP2, F2-IsoP3, and F2-IsoP4) were quantified using liquid chromatography/ tandem mass spectrometry and adjusted for urinary creatinine levels. Hypertension was assessed at baseline and follow-up visits and defined as systolic blood pressure \u3e 140 mm Hg and/or diastolic blood pressure \u3e 90 mm Hg and/or currently taking antihypertensive medications. Crude associations between study population characteristics and hypertensive status were analyzed with the chi-square and Wilcoxon-rank sum tests. Crude associations between study population characteristics and F2-isoprostane levels were analyzed with Wilcoxon-rank sum, Kruskal-Wallis, and Spearman’s rank correlation measures. Finally, the adjusted prospective associations between hypertensive status and F2-isoprostane concentrations were modeled using logistic regression. Results: Of the 844 participants who were included in the study, 258 (31%) were classified as hypertensive at baseline. Among the 586 participants who were normotensive at baseline, 123 (21%) developed hypertension over the five-year study period. Importantly, none of four F2-isoprostane isomers predicted a significant increase in the odds of developing hypertension, as indicated by their odds ratio 95% confidence intervals; F2-IsoP1: (0.85, 1.31), F2-IsoP2: (0.62, 1.13), F2-IsoP3: (0.80, 1.27), and F2-IsoP4: (0.84, 1.29). Conclusion: Previous studies have investigated the association between oxidative status and hypertension prevalence, however the cross sectional nature of the study designs have made it difficult to establish temporality between exposure and outcome. To our knowledge, this is the first study to model the odds of developing hypertension as a function of F2-isoprostane levels. The results of this study suggest that oxidative status is not involved in the development of hypertension

Cardiorespiratory Fitness, Metabolic Risk, and Inflammation in Children

The aim of this study was to investigate the independent associations among cardiorespiratory fitness, metabolic syndrome (MetS), and C-reactive protein (CRP) in children. The sample consisted of 112 children (11.4  ±  0.4 years). Data was obtained for children's anthropometry, cardiorespiratory fitness, MetS components, and CRP levels. MetS was defined using criteria analogous to the Adult Treatment Panel III definition. A MetS risk score was also computed. Prevalence of the MetS was 5.4%, without gender differences. Subjects with low fitness showed significantly higher MetS risk (P < 0.001) and CRP (P < 0.007), compared to the high-fitness pupils. However, differences in MetS risk, and CRP between fitness groups decreased when adjusted for waist circumference. These data indicate that the mechanisms linking cardiorespiratory fitness, MetS risk and inflammation in children are extensively affected by obesity. Intervention strategies aiming at reducing obesity and improving cardiorespiratory fitness in childhood might contribute to the prevention of the MetS in adulthood