Ideal Cardiovascular Health and Adiposity: Implications in Youth

Association between endogenous sex hormones and adiposity in youth across a weight status spectrum

BACKGROUND

While endogenous sex hormones (e.g., testosterone, estradiol) are important factors regulating adipose tissue distribution, studies evaluating such relationships in youth across a wide weight status spectrum are limited.

METHODS

We performed a cross-sectional analysis of 8-21-year-old youth. Multiple linear regression models were used to evaluate associations between sex hormones and adiposity measures (android/gynoid ratio (A/G), total fat mass (FM), visceral adipose tissue (VAT), waist circumference (WC)) and total lean mass (LM), adjusting for pubertal stage and race/ethnicity, and stratified by sex and weight status.

RESULTS

Among 342 youth, the mean age was 13.0 ± 2.8 years old (52.6% female; 38.9% normal weight [NW]; 27.8% overweight/obesity [OW/OB]; 33.3% severe obesity [SO]). Testosterone was positively associated with LM among males with NW (1462 g, 95% CI: 255-2668 g) and OW/OB (3792 g, 95% CI: 1244-6340 g), with A/G and WC among males with NW (0.01, 95% CI: 0-0.2 and 10 mm, 95% CI: 4-16 mm, respectively), and negatively associated with WC among males with SO (-43 mm, -81 to -5 mm). Estradiol was positively associated with A/G, FM, and WC among males with SO, and VAT in females with NW.

CONCLUSION

Our findings showed that sex hormones were associated with adipose tissue deposition in youth across the weight spectrum.

IMPACT STATEMENT

Sex hormones (e.g., testosterone, estradiol) are associated with various adiposity measures among male and female children and adolescents across a weight status spectrum. We evaluated associations between sex hormones and various adiposity measures among 8-21-year-olds across a weight status spectrum (normal weight, overweight/class 1 obesity, class 2-3 obesity). We found that estradiol was positively associated with total fat mass, android/gynoid ratio, and waist circumference in males with class 2-3 obesity, and testosterone was positively associated with lean mass in males with normal weight and overweight/class 1 obesity. Sex hormones may influence, or may be influenced by, adiposity in youth.

Sociodemographic Correlates of High Cardiovascular Health Across Childhood and Adolescence: A Prospective Study Among 2 Cohorts in the ECHO Consortium

BACKGROUND

This study seeks to characterize cardiovascular health (CVH) from early childhood to late adolescence and identify sociodemographic correlates of high CVH that serve as levers for optimizing CVH across early life.

METHODS AND RESULTS

Among 1530 youth aged 3 to 20 years from 2 cohorts in the ECHO (Environmental Influences on Child Health Outcomes) consortium, we first derived CVH scores on the basis of the Life's Essential 8 construct comprising 4 behavioral (nicotine use/exposure, physical activity, sleep, and diet) and 4 health factors (body mass index, blood pressure, non-high-density lipoprotein cholesterol, and fasting glucose) during early childhood (mean age, 3.5 years), middle childhood (8.0 years), early adolescence (13.3 years), and late adolescence (17.8 years). Next, we used generalized regression to estimate the probability of high (versus not high) CVH with respect to sociodemographic characteristics. Overall CVH score was stable across life stages: 81.2±7.6, 83.3±8.0, and 81.7±8.9 of 100 possible points in early childhood, middle childhood, and early adolescence, respectively. Accordingly, during these life stages, most children (63.3%-71.5%) had high CVH (80 to <100). However, CVH declined by late adolescence, with an average score of 75.5±10.2 and 39.4% high CVH. No children had optimal CVH (score=100) at any time. Correlates of high CVH include non-Hispanic White race and ethnicity, maternal college education, and annual household income >$70 000. These associations were driven by behavioral factors.

CONCLUSIONS

Although most youth maintained high CVH across childhood, the decline by late adolescence indicates that cardiovascular disease prevention should occur before the early teen years. Disparities in high CVH over time with respect to sociodemographic characteristics were explained by behavioral factors, pointing toward prevention targets.

Assessing Life's Essential 8 and Adverse Childhood Experiences in Grandparent-Grandchild Co-residing Dyads

We assessed a subset of behavioral indicators from the American Heart Association Life's Essential 8 cardiovascular health (CVH) construct-diet, physical activity, sleep, and nicotine exposure-and quantified associations in scores between members of 12 grandparent-grandchild dyads (grandparents, 52-70 years old; children, 7-12 years old). We also assessed the number of adverse childhood experiences from the dyads. Using the Life's Essential 8 scoring algorithm (0-100, with 100 as optimal), we calculated averages and used Spearman's ρ correlation to quantify associations. Mean score was 67.5 (±12.4) for grandparents and 63.0 (±11.2) for grandchildren. Mean scores for the dyad members were significantly correlated ( r = 0.66, P < .05). The mean numbers of adverse childhood experiences were 7.0 and 5.8 for the grandparents and grandchildren, respectively. The results indicate that CVH in these dyads was suboptimal and interrelated. Adverse childhood experiences in this analysis surpass levels reported as high risk for poor CVH. Our findings suggest that dyadic-based interventions to improve CVH are warranted.

Application of Life's Essential 8 to assess cardiovascular health during early childhood

PURPOSE

Assess cardiovascular health (CVH) during early childhood using the American Heart Association's recently updated construct, Life's Essential 8 (LE8); examine concordance in CVH status per LE8 versus Life's Simple 7 (LS7); and identify perinatal correlates of high CVH per LE8.

METHODS

We applied LE8 and LS7 to data from 305 children aged 4-7 years in Denver, CO; estimated % low, moderate, high, and optimal CVH; assessed concordance in CVH status based on LE8 and LS7 using contingency tables; and used multivariable logistic regression to identify early-life correlates of high CVH per LE8.

RESULTS

Average age of children was 4.7 ± 0.6 years, 44.6% were female. No participants had low or optimal CVH, 43.9% had high, and 56.1% had moderate CVH per LE8, whereas 33.4% had high and 66.6% had moderate CVH per LS7. Twenty-two percent had high CVH based on both constructs. Correlates of high CVH were maternal prenatal diet quality (odds ratioHealthy Eating Index score>vs. ≤57 = 1.90 [1.12, 3.21]) and child age (odds ratioper 1 year = 1.58 [1.04. 2.42]).

CONCLUSIONS

LE8 yielded higher prevalence of high CVH than LS7 during early childhood, though there is modest concordance between the two constructs. Maternal diet is a potential modifiable target to optimize early-life CVH.

Appraisal of Clinical Care Practices for Child Obesity Treatment. Part II: Comorbidities

The objective of this technical report is to provide clinicians with actionable evidence-based information upon which to make treatment decisions. In addition, this report will provide an evidence base on which to inform clinical practice guidelines for the management and treatment of overweight and obesity in children and adolescents. To this end, the goal of this report was to identify all relevant studies to answer 2 overarching key questions: (KQ1) "What are effective clinically based treatments for obesity?" and (KQ2) "What is the risk of comorbidities among children with obesity?" See Appendix 1 for the conceptual framework and a priori Key Questions.

Relationship of Endothelial Microparticles to Obesity and Cardiovascular Disease Risk in Children and Adolescents

Background

Microparticles and endothelial microparticles (EMPs) are implicated in accelerating cardiovascular disease (CVD); however, data in pediatrics are limited. We examined the relationship of microparticles and EMPs with adiposity and subclinical CVD risk measures in a pediatric population to determine their potential as biomarkers of CVD risk.

Methods and Results

A cross‐sectional study of youth (n=280; ages 8–20 years) with a range of body mass index categories was used. Microparticles, EMPs, and activated EMPs were measured by flow cytometry. %Body fat and %visceral adipose tissue were measured by dual X‐ray absorptiometry. Measures of arterial stiffness and vascular wall structure were obtained. Linear regression (with log‐transformed outcomes) and logistic regression were used to evaluate associations and all results were exponentiated. Youth with overweight/obesity and severe obesity had 2.50 (95% CI, 1.56–4.01) and 3.42 (95% CI, 2.15–5.43) times the geometric means of the total number of microparticles, respectively, compared with those with normal weight. Youth with overweight/obesity and severe obesity had 1.97 (95% CI, 1.09–3.55) and 2.34 (95% CI, 1.31–4.19) times the geometric means of the total number of EMPs, respectively, compared with those with normal weight. There were positive associations between the levels of both microparticles and EMPs with higher adiposity measures and poor CVD risk measures. Youth with higher adiposity showed 1.84 times the odds of having high levels of activated EMPs (%) (odds ratio, 1.84; 95% CI, 1.08–3.14) compared with those with normal weight.

Conclusions

Levels of microparticles, EMPs, and activated EMPs were positively associated with adiposity and poor subclinical CVD risk in a pediatric population.

Ideal Cardiovascular Health in adolescents: Findings from Study of Cardiovascular Risks in Adolescents

BACKGROUND AND AIM

We assessed the Ideal Cardiovascular Health (CVH) in Brazilian adolescents according to demographics and socioeconomic characteristics.

METHODS AND RESULTS

This is a cross-sectional study with data from the Study of Cardiovascular Risks in Adolescents (ERICA), with a nationwide representative sample of 36,956 Brazilian adolescents, aged 12-17 years, enrolled in public and private schools. The CVH metrics considered were body mass index (BMI), physical activity, smoking, healthy diet score, blood pressure, fasting plasma glucose, and total cholesterol. The demographics and socioeconomic characteristics analyzed were sex, age, race/skin color, and type of school attended. The study design was considered, and the significant difference determined by the non-overlapping of 95% Confidence Interval. The mean ideal CVH score was 4.0, higher for females, adolescents aged 15-17 years, and students from private schools. The prevalence of ideal fasting plasma glucose was 96%, of non-smoking 95.6%, of ideal blood pressure 75.5%, of ideal BMI 73.2%, of ideal total cholesterol 55.4%, of ideal physical activity 45.2%, and only 0.5% had an ideal diet. The prevalence of ideal CVH metrics varied according to demographics and socioeconomic characteristics.

CONCLUSION

Females, older adolescents, and students who attended private school had a better CVH. Demographics and socioeconomic characteristics were associated with CVH metrics. The low ideal proportions found for diet and physical activity are of concern and reinforce the need for food and nutritional educational actions designed to promote healthy behaviors in adolescence to prevent the development of cardiovascular diseases.

Assessing Cardiometabolic Health Risk Among U.S. Children Living in Grandparent-Headed Households

PURPOSE

We evaluated children's cardiometabolic health (CMH) risk indicators and adverse childhood experiences (ACEs) stratified by family structure type (grandparent-headed, two-parent headed, and single-parent headed households). Separately, we assessed whether family structure type and number of ACEs were independently associated with the CMH risk indicators.

DESIGN AND METHODS

Utilizing data from the 2017-2018 National Survey of Children's Health, we evaluated five CMH risk indicators (obesity, physical activity, secondhand smoke exposure, sleep, and sports participation). We used multivariable logistic regressions to assess the association of CMH risk indicators with family structure type and ACEs. We controlled for sex, age, race/ethnicity, health insurance, household poverty level, and overall health status.

RESULTS

Among children aged 10-17 years (n = 24,885), we found the number of ACEs differed by family structure type (P < 0.001) and was independently associated with obesity, secondhand smoke exposure, sleep, and sports participation. Adjusting for all covariates except ACEs, family structure type was significantly associated with children's CMH risk; but after controlling for ACEs that association was attenuated - except for sleep (less adequate sleep in grandparent-headed households) and exposure to secondhand smoke (less exposure in single-parent headed households).

CONCLUSIONS

ACEs were highest among children living in grandparent-headed households and independently associated with a majority of the CMH risk indicators. Findings suggest that children living in grandparent-headed households may be at elevated risk for poor CMH, potentially due to higher risk for ACEs.

PRACTICE IMPLICATIONS

It is recommended to consider ACEs and family structure type when assessing CMH risk in children.

BMI metrics and their association with adiposity, cardiometabolic risk factors, and biomarkers in children and adolescents

BACKGROUND

There are limited data comparing the relative associations of various BMI metrics with adiposity and cardiometabolic risk factors in youth.

OBJECTIVE

Examine correlations of 7 different BMI metrics with adiposity, cardiometabolic risk factors, and biomarkers (i.e. blood pressure, waist circumference, cholesterol, leptin, insulin, high molecular weight adiponectin, high-sensitivity c-reactive protein (hsCRP)).

METHODS

This was a cross-sectional analysis of youth in all BMI categories. BMI metrics: BMI z-score (BMIz), extended BMIz (ext.BMIz), BMI percentile (BMIp), percent of the BMI 95th percentile (%BMI_p95), percent of the BMI median (%BMI_p50), triponderal mass index (TMI), and BMI (BMI). Correlations between these BMI metrics and adiposity, visceral adiposity, cardiometabolic risk factors and biomarkers were summarized using Pearson's correlations.

RESULTS

Data from 371 children and adolescents ages 8-21 years old were included in our analysis: 52% were female; 20.2% with Class I obesity, 20.5% with Class II, and 14.3% with Class III obesity. BMIp consistently demonstrated lower correlations with adiposity, risk factors, and biomarkers (r = 0.190-0.768) than other BMI metrics. The %BMI_p95 and %BMI_p50 were marginally more strongly correlated with measures of adiposity as compared to other BMI metrics. The ext.BMIz did not meaningfully outperform BMIz.

CONCLUSION

Out of all the BMI metrics evaluated, %BMI_p95 and %BMI_p50 were the most strongly correlated with measures of adiposity. %BMI_p95 has the benefit of being used currently to define obesity and severe obesity in both clinical and research settings. BMIp consistently had the lowest correlations. Future research should evaluate the longitudinal stability of various BMI metrics and their relative associations with medium to long-term changes in adiposity and cardiometabolic outcomes in the context of intervention trials.

Pre- and Perinatal Correlates of Ideal Cardiovascular Health during Early Childhood: A Prospective Analysis in the Healthy Start Study

OBJECTIVES

To characterize prevalence of ideal cardiovascular health (ICVH) during early childhood (4-7 years of age), and to identify pre- and perinatal biological, sociodemographic, metabolic, and behavioral correlates of ICVH.

STUDY DESIGN

Among 350 mother-child pairs in the Healthy Start Study, we defined ICVH as no exposure to second hand smoke; ≥1 hour/day of moderate-to-vigorous physical activity; body mass index ≤85th percentile; systolic and diastolic blood pressure <90th percentile; cholesterol <170 mg/dL, fasting glucose <100 mg/dL; and healthy diet, per the American Heart Association. Pre- and perinatal characteristics were obtained from questionnaires, medical records, and in-person visits. Because of low prevalence of ICVH, we focused on prevalence of meeting ≥6 metrics in the analysis. We examined bivariate associations of each characteristic with % meeting ≥6 metrics and included those that were significant (P < .05) in a multivariable logistic regression model.

RESULTS

ICVH prevalence at mean ± SD age 4.7±0.6 years was 6.9%; boys had twice the prevalence as girls (9% vs 4.4%). Most (>85%) children met criteria for second hand smoke, body mass index, blood pressure, cholesterol, and glucose, and only one-third met criteria for physical activity (31.4%) and diet (35.1%). In multivariable analyses, key correlates of ICVH were maternal weight status (ORoverweight/obese vs nonoverweight/obese = 0.41 [0.23, 0.73]) and offspring sex (ORmale vs female = 2.14 [1.22, 3.65]).

CONCLUSIONS

At age 4-7 years, ICVH prevalence is already low, with diet and adequate physical activity being the limiting factors. Healthy maternal weight prior to pregnancy and male sex are potential determinants of childhood ICVH. Additional work is required to explore associations of early-life ICVH with future health outcomes.

Physical Activity, Cardiorespiratory Fitness and Clustered Cardiovascular Risk in South African Primary Schoolchildren from Disadvantaged Communities: A Cross-Sectional Study

The coexistence of multiple cardiovascular risk factors has been reported in school-aged children from the age of nine years, but most evidence stems from high-income countries. This cross-sectional study aimed at describing the cardiovascular health risk, physical activity (PA) behavior and cardiorespiratory fitness (CRF) levels of South African primary schoolchildren, and at examining the associations between PA/CRF and a composite measure of cardiovascular risk. Cross-sectional data from 832 primary schoolchildren (grade 1–4) were analyzed. Total cholesterol/HDL ratio, triglycerides, systolic/diastolic blood pressure, body fat, and glycated hemoglobin were assessed as cardiovascular risk markers. Data were analyzed via mixed linear regressions and analyses of covariance. Overall, 24.2% of the participants did not meet current PA standards. Higher CRF/PA were associated with lower body fat and lower clustered cardiovascular risk (p < 0.05). When categorizing children into CRF/PA quartiles, a lower clustered cardiovascular risk gradient was found in children with higher CRF (p < 0.05) or PA (p < 0.05). Our data shows that higher CRF/PA is associated with lower clustered cardiovascular risk already from a young age. Given that clustered cardiovascular risk present during childhood can track into adulthood, we advocate for PA participation and a healthy weight from a young age onwards.

Relationship of Circulating Endothelial Cells With Obesity and Cardiometabolic Risk Factors in Children and Adolescents

Background Circulating endothelial cells (CECs) reflect early changes in endothelial health; however, the degree to which CEC number and activation is related to adiposity and cardiovascular risk factors in youth is not well described. Methods and Results Youth in this study (N=271; aged 8-20 years) were classified into normal weight (body mass index [BMI] percentage <85th; n=114), obesity (BMI percentage ≥95th to <120% of the 95th; n=63), and severe obesity (BMI percentage ≥120% of the 95th; n=94) catagories. CEC enumeration was determined using immunohistochemical examination of buffy coat smears and activated CEC (percentage of vascular cell adhesion molecule-1 expression) was assessed using immunofluorescent staining. Cardiovascular risk factors included measures of body composition, blood pressure, glucose, insulin, lipid profile, C-reactive protein, leptin, adiponectin, oxidized low-density lipoprotein cholesterol, carotid artery intima-media thickness, and pulse wave velocity. Linear regression models examined associations between CEC number and activation with BMI and cardiovascular risk factors. CEC number did not differ among BMI classes (P>0.05). Youth with severe obesity had a higher degree of CEC activation compared with normal weight youth (8.3%; 95% CI, 1.1-15.6 [P=0.024]). Higher CEC number was associated with greater body fat percentage (0.02 per percentage; 95% CI, 0.00-0.03 [P=0.020]) and systolic blood pressure percentile (0.01 per percentage; 95% CI, 0.00-0.01 [P=0.035]). Higher degree of CEC activation was associated with greater visceral adipose tissue (5.7% per kg; 95% CI, 0.4-10.9 [P=0.034]) and non-high-density lipoprotein cholesterol (0.11% per mg/dL; 95% CI, 0.01-0.21 [P=0.039]). Conclusions Methods of CEC quantification are associated with adiposity and cardiometabolic risk factors and may potentially reflect accelerated atherosclerosis as early as childhood.

Associations between paediatric fatigue and eating behaviours

BACKGROUND

In adults, poor sleep quality is associated with increased obesogenic eating behaviours; less is known about this relationship in youth. The objectives of this study were to assess the strength of association between fatigue-related quality of life (QoL) and eating behaviours among youth and to describe the associations in participants with percent body fat (%BF) above and below the 90th percentile for sex and age.

METHODS

Caregiver-reported measures of fatigue (Pediatric QoL Multidimensional Fatigue Scale) and eating behaviours (Child Eating Behaviour Questionnaire) were obtained from participants aged 8-17 years. %BF was measured by iDXA and grouped by sex- and age-specific percentiles. Multiple linear regression adjusting for age, sex and race/ethnicity was used.

RESULTS

Of the 352 participants (49% male), 44.6% had %BF >90th percentile. General, sleep/rest and cognitive fatigue QoL was inversely associated with food approach behaviours: food responsiveness, enjoyment of food, emotional overeating and desire to drink. For participants with %BF >90th percentile, higher general fatigue QoL was associated with higher satiety responsiveness (0.13; 95% confidence interval [CI 0.03, 0.24]). For participants with %BF ≤90th percentile, higher general fatigue QoL was associated with less satiety responsiveness (-0.16; 95% CI [-0.31, -0.01]).

CONCLUSION

Less fatigue symptoms were associated with less behaviours associated with food approach among paediatric participants. For participants with %BF >90th percentile, less symptoms of general fatigues corresponded with more satiety. Though causation has yet to be established, youth with elevated %BF should be screened for fatigue symptoms and offered counselling on sleep hygiene or a sleep medicine referral to help mitigate weight gain.

The association of ideal cardiovascular health with self-reported health, diabetes, and adiposity in African American males

African American (AA) men have the highest age-adjusted all-cause mortality rate in the United States of America (US) and a high burden of cardiovascular risk factors. The African American Male Wellness Walk (AAMWW) seeks to reduce such health disparities among AA males. The association of a combination of ideal cardiovascular health (ICH) metrics (blood pressure, glucose, cholesterol, body mass index (BMI), physical activity, and smoking) with self-reported health, diabetes, and body fat percentage was examined among 729 AA male participants from the 2017 and 2018 AAMWWs. Six metrics of ICH were categorized into a three-tiered ICH score 0-2, 3-4, 5-6. Linear and logistic regression modeling was performed with adjustment for age and insurance. Seven percent of men attained 5-6 ICH metrics at baseline. Participants with 5-6 ICH metrics versus 0-2 had 256% higher odds of excellent self-reported health compared to good, fair or poor (p < 0.0001). After exclusion of glucose from the ideal cardiovascular health score, participants with 3-4 versus 0-2 ICH metrics had a 48% lower odds of diabetes (p < 0.0031). After exclusion of BMI from the ICH score, participants with 5 ICH metrics had a 14.1% lower body fat percentage versus participants with 0-2 ICH metrics (p = 0.0057). Attainment of higher ideal cardiovascular health scores is associated with higher odds of self-reported health, lower odds of diabetes and lower body fat percentage among AA men. Future strategies leading to greater attainment of cardiovascular health in AA males will be important to advance health equity.

Reaching the Tipping Point: Identification of Thresholds at which Visceral Adipose Tissue May Steeply Increase in Youth

OBJECTIVE

This study aimed to determine whether children and adolescents demonstrate, similarly to adults, a threshold of total percent body fat (%BF) above which the slope of visceral adipose tissue (VAT) rises.

METHODS

This cross-sectional study included 557 youth, aged 8 to 18 years, with a wide range of BMI values. Dual-energy x-ray absorptiometry was used to determine body composition (including VAT), and fasting blood was collected for measurement of lipids, glucose, insulin, and biomarkers. Segmented linear regression analysis identified the threshold for %BF unadjusted and adjusted for Tanner stage. Linear regression with robust variance estimation compared associations of risk factors and thresholds.

RESULTS

Thresholds of %BF were identified by sex (males = 33%, females = 38%), age (< 12 years = 34%; ≥ 12 years = 30%), and race (White/non-Hispanic = 31%; all other races/Hispanic = 38%) above which the slope of VAT was significantly steeper (all P < 0 .001). The percentage of total body fat stored as VAT was higher above versus below these thresholds (all P < 0.001). Above threshold, but not below it, VAT was associated with triglycerides/high-density lipoprotein ratio, insulin, adiponectin, and blood pressure.

CONCLUSIONS

The thresholds should be confirmed in longitudinal studies, and they may be useful in identifying youth at increased cardiometabolic risk in need of close clinical monitoring and/or intensive intervention to reduce excess adiposity.

Lifestyles and Cardiovascular Prevention in Childhood and Adolescence

Pathology studies demonstrated that coronary fatty streaks develop early in life and that even more advanced fibrous plaques are present in a proportion of adolescents. The presence and extent of atherosclerosis in children and adolescents can be correlated with the same risk factors present in adults; as well as, childhood levels of these risk factors predict adult cardiovascular diseases. Children are born with ideal cardiovascular health but, unfortunately, most of them develop over time modifiable behavioral risk factors. Achieving sustained lifestyle changes initiated too late in adults is difficult, and pharmacologic risk factor control cannot fully restore a low-risk state. Therefore, it seems eminently reasonable to initiate healthful lifestyle training as early in life, decreasing the prevalence of cardiovascular risk factors to retard atherogenic processes and reduce the future burden of cardiovascular diseases. Many guideline recommendations encourage universal adoption of healthier lifestyles, identification of children with cardiovascular risk factors, and their treatment using targeted lifestyle modification and, rarely, pharmacotherapy. Major gains will likely accrue from public health strategies targeting incorrect diet, physical activity, and cigarette smoking. Individualized strategies, however, will initially focus on the highest risk children such as those with familial hyperlipidaemia, diabetes, hypertension, and obesity. The primary purpose of this article is to provide a broad overview on the long-term cardiovascular effects of risk factors in children and youth and to outline various lines of evidence for the efficacy of primordial and primary prevention in young people, as well as recommendations for population- and individual-level strategies and evidence-based interventions.

Physical Activity Improves Lipid and Weight-Loss Outcomes After Metabolic Bariatric Surgery in Adolescents with Severe Obesity

OBJECTIVE

This study tested the hypothesis that physical activity improves cardiovascular disease-related lipids beyond that associated with weight loss in adolescents with severe obesity after metabolic/bariatric surgery (MBS).

METHODS

Objective activity monitor data from 108 participants of the Teen Longitudinal Assessment of Bariatric Surgery (Teen-LABS) study from baseline to 3 years post MBS were used. Primary outcomes included absolute change in LDL cholesterol (LDL-C) and non-HDL cholesterol (non-HDL-C) from baseline. Baseline measurement, visit, surgical procedure, and percent change in iliac waist circumference or BMI from baseline in linear regression models were adjusted for use of generalized estimating equations. PROC TRAJ in SAS generated optimal activity trajectories based on individual step count.

RESULTS

Despite low step counts and slow cadence, differences by activity trajectory were found. Greater absolute decreases in LDL-C and non-HDL-C (-15 mg/dL [95% CI: -28 to -2], P  = 0.026; and -15 mg/dL [95% CI: -28 to -1], P  = 0.035), respectively, were associated with more activity. More activity was associated with greater resolution of triglycerides, LDL-C, and non-HDL-C dyslipidemia and with greater weight loss 3 years post MBS.

CONCLUSIONS

More activity in adolescents was associated with improvements in cardiovascular disease-related lipid measures and weight loss after MBS.

The influence of cardiorespiratory fitness on clustered cardiovascular disease risk factors and the mediator role of body mass index in youth: The UP&DOWN Study

BACKGROUND

The combined effect of cardiorespiratory fitness (CRF) and body mass index (BMI) on cardiovascular disease (CVD) risk in young people remains to be fully determined. We examined the individual and combined associations of CRF and BMI with clustered CVD risk factors, and the mediator role of BMI in the association between CRF and clustered CVD risk factors in children and adolescents.

METHODS

237 children (111 girls) and 260 adolescents (120 girls) were included in this cross-sectional study. Height and weight were assessed and BMI was calculated. A CVD risk factor index (CVDRF-I) was computed from: waist circumference, systolic blood pressure, triglycerides, high-density lipoprotein cholesterol and glucose. CRF was assessed using the 20-m shuttle run test. Regression analysis, analysis of covariance and mediation analysis (Baron and Kenny procedures) were used to test the independent and combined effect of CRF and BMI on CVDRF-I, and to test mediation hypothesis, respectively.

RESULTS

CRF was negatively associated with CVDRF-I (all P < 0.05); however, after adjusting for BMI the associations were no longer significant in children and adolescents of both sex groups. Contrary, the association between BMI and CVDRF-I was independent of CRF (all P < 0.001). The effect of CRF on CVDRF-I was mediated by BMI. The percentage of the total effect of CRF on CVDRF-I mediated by BMI for boys and girls children and boys and girls adolescents were 79.5%, 100%, 81.2% and 55.7%, respectively.

CONCLUSIONS

BMI is an independent predictor of CVDRF-I and a mediator of the association between CRF and CVDRF-I in children and adolescents. These results help to clarify the associations between CRF, weight status and cardiovascular health, suggesting that future CVD health would benefit from maintaining an optimal weight status.