Objectively measured daily physical activity related to cardiac size in young children

Associations Between Sedentary Time, Physical Activity, and Cardiovascular Health in 6-Year-Old Children Born to Mothers With Increased Cardiometabolic Risk

PURPOSE

To assess associations between sedentary time (ST), physical activity (PA), and cardiovascular health in early childhood.

METHOD

Cross-sectional study including 160 children (age 6.1 y [SD 0.5], 86 boys, 93 maternal body mass index ≥ 30 kg/m2, and 73 gestational diabetes) assessed for pulse wave velocity, echocardiography, ultra-high frequency 48-70 MHz vascular ultrasound, and accelerometery.

RESULTS

Boys had 385 (SD 53) minutes per day ST, 305 (SD 44) minutes per day light PA, and 81 (SD 22) minutes per day moderate to vigorous PA (MVPA). Girls had 415 (SD 50) minutes per day ST, 283 (SD 40) minutes per day light PA, and 66 (SD 19) minutes per day MVPA. In adjusted analyses, MVPA was inversely associated with resting heart rate (β = -6.6; 95% confidence interval, -12.5 to -0.7) and positively associated with left ventricular mass (β = 6.8; 1.4-12.3), radial intima-media thickness (β = 11.4; 5.4-17.5), brachial intima-media thickness (β = 8.0; 2.0-14.0), and femoral intima-media thickness (β = 1.3; 0.2-2.3). MVPA was inversely associated with body fat percentage (β = -3.4; -6.6 to -0.2), diastolic blood pressure (β = -0.05; -0.8 to -0.1), and femoral (β = -18.1; -32.4 to -0.8) and radial (β = -13.4; -24.0 to -2.9) circumferential wall stress in boys only. ST and pulse wave velocity showed no significant associations.

CONCLUSIONS

In young at-risk children, MVPA is associated with cardiovascular remodeling, partly in a sex-dependant way, likely representing physiological adaptation, but ST shows no association with cardiovascular health in early childhood.

Early cardiac abnormalities in obese children and their relationship with adiposity

OBJECTIVES

Childhood obesity rates are increasing as well as chronic disease and cardiovascular risk factors for patients at young ages. In this study, we evaluate the correlation between cardiac parameters, body mass index (BMI), and other body composition indicators in children and adolescents.

METHODS

In this cross-sectional study, we evaluated anthropometric measurements, bioelectrical impedance parameters, and echocardiographic measurements including the left ventricular mass (LVM), LVM index (LVMI), and left atrial diameter (LAD) in children and adolescents ages 7 to 15 y. We performed linear and multivariate regression analyses and analyzed the correlations between cardiac parameters, BMI, and other body composition parameters.

RESULTS

We analyzed 96 children and adolescents and found 40.6% to be obese and 29.2% overweight. LVMI and LAD indexed to height were significantly higher in individuals who were obese. LVMI increased significantly with increasing BMI (r = 0.717; P < 0.001), waist circumference (r = 0.670; P < 0.001), waist-to-height ratio (r = 0.650; P < 0.001), and body surface (r = 0.570; P < 0.001). Only BMI was significant in the multivariate analysis. LVMI was directly and positively correlated with fat mass (FM) and percentage of visceral and abdominal FM and negatively correlated with percentage of lean body mass. LAD was significantly correlated with body surface (r = 0.728; P < 0.001), BMI (r = 0.611; P < 0.001), waist circumference (r = 0.614; P < 0.001), and waist-to-height ratio (r = 0.341; P < 0.01). When indexed to height, LAD was only correlated with BMI and waist-to-height ratio.

CONCLUSIONS

Obesity is associated with cardiac disturbances at a very early age and these changes are closely related to the degree of adiposity. Cardiac structural parameters are significantly correlated with BMI and waist circumference in pediatric patients ages 7 to 15 y.

Aerobic fitness related to cardiovascular risk factors in young children

Low aerobic fitness (maximum oxygen uptake (VO(2 PEAK))) is predictive for poor health in adults. In a cross-sectional study, we assessed if VO(2 PEAK) is related to a composite risk factor score for cardiovascular disease (CVD) in 243 children (136 boys and 107 girls) aged 8 to 11 years. VO(2 PEAK) was assessed by indirect calorimetry during a maximal exercise test and scaled by body mass (milliliters per minute per kilogram). Total body fat mass (TBF) and abdominal fat mass (AFM) were measured by Dual-energy X-ray absorptiometry. Total body fat was expressed as a percentage of total body mass (BF%) and body fat distribution as AFM/TBF. Systolic and diastolic blood pressure (SDP and DBP) and resting heart rate (RHR) were measured. The mean artery pressure (MAP) and pulse pressure (PP) were calculated. Echocardiography, 2D-guided M-mode, was performed. Left atrial diameter (LA) was measured and left ventricular mass (LVM) and relative wall thickness (RWT) were calculated. Z scores (value for the individual - mean value for group)/SD were calculated by sex. The sum of z scores for DBP, SDP, PP, MAP, RHR, LVM, LA, RWT, BF%, AFM and AFM/TBF were calculated in boys and girls, separately, and used as composite risk factor score for CVD. Pearson correlation revealed significant associations between VO(2 PEAK) and composite risk factor score in both boys (r = -0.48 P < 0.05) and in girls (r = -0.42, P < 0.05). One-way ANOVA analysis indicated significant differences in composite risk factor score between the different quartiles of VO(2 PEAK) (P < 0.001); thus, higher VO(2 PEAK) was associated with lower composite risk factor score for CVD. In conclusion, low VO(2 PEAK) is associated with an elevated composite risk factor score for CVD in both young boys and girls.

Cardiovascular impact of the pediatric obesity epidemic: higher left ventricular mass is related to higher body mass index

OBJECTIVE

To compare secular changes in body mass index (BMI) and left ventricular mass (LVM) in today's children versus children of a generation earlier.

STUDY DESIGN

All healthy patients aged 2 to 19 years who underwent echocardiography at a single US academic medical center in 1986 to 1989 (prior era) and 2008 (current era) were included in this retrospective cross-sectional study. BMI, BMI z score, LVM indexed to height (LVMI), LVM z score, and relative wall thickness were calculated. Cardiac geometries were assigned based on LVM z score and relative wall thickness and classified as normal, concentric hypertrophy, eccentric hypertrophy, or concentric remodeling. Stepwise regression analysis was performed to identify determinants of LVMI.

RESULTS

There were 350 subjects in the prior era and 350 age- and sex-matched subjects in the current era. Mean BMI and LVMI were both significantly higher in the current era than in the prior era (BMI, 19.9 ± 5.6 kg/m(2) vs 18.1 ± 3.8 kg/m(2), P = .0004; LVMI, 32.7 ± 7.8 g/m(2.7) vs 31.5 ± 8.1 g/m(2.7); P = .02). Determinants of LVMI in both eras were BMI z score, younger age, male sex, and African-American race.

CONCLUSIONS

Today's children have higher BMI, LVMI, and predicted cardiovascular risk than their counterparts a generation earlier. Reversal of these trends is needed, and intervention is required.

Lack of physical activity in young children is related to higher composite risk factor score for cardiovascular disease

AIM

This study evaluates whether accelerometer-measured physical activity is related to higher composite risk factor scores for cardiovascular disease (CVD) in children.

METHODS

Cross-sectional study that included 223 children aged 7.9-11.1 years (boys n = 123, girls n = 100). Daily physical activity was assessed by accelerometers for 4 days. Body fat was quantified by dual X-ray absorptiometry. Maximal oxygen uptake was measured during a maximal exercise test. Resting heart rate and blood pressure were measured. Z-scores [(value for the individual - mean value for group)/SD] were calculated for each variable, and the sum of different risk factor z-scores used as an index of composite risk factors score for CVD.

RESULTS

Partial correlations, from General Linear Model, between moderate to vigorous physical activity (MVPA), vigorous physical activity (VPA) and general physical activity versus index of composite risk factor score were in boys 0.29, 0.33 and 0.30 (all p < 0.05), respectively. The corresponding correlations in girls were -0.28, -0.32 (both p < 0.05) and -0.18 (NS), respectively.

CONCLUSION

Low amounts of MVPA and VPA were related to higher composite risk factor scores for CVD in children aged 8-11 years.

Cardiovascular screening in young athletes in Sarajevo Canton

Potential risk of sudden death during sports participation makes screening of competitive athletes of vital importance. Congenital cardiac anomalies and non-atherosclerotic, acquired myocardial conditions are primary causes underlying exercise-induced cardiac death in young patients. Since cardiovascular conditions are the leading causes of non-traumatic, exercise-induced cardiac events, cardiovascular screening preceding sports participation in mandatory. The objectives of this study were to determine prevalence of cardiac conditions through cardiovascular screening of young athletes and to establish preventive strategy. The study was conducted at the Sports Medicine Center of Sarajevo Canton and at the Pediatric Clinic of University of Sarajevo Clinics Centre in the period 2007-2009. The study was supported by Canton Sarajevo Ministry of Health and Ministry of sports, science and culture. The study targeted a group of 214 athletes, 8-18 years of age with average age being 15.26. The group was subdivided into five groups according to the age. After taking the anamnesis (family, personal and cardiological) patients were subjected to the measuring of body mass and height, blood pressure and heart rate and oxygen saturation, recording of 12-lead ECG, specialist examination (pediatrician, sports medicine specialist and cardiologist) and complete heart echocardiography. No examined athletes expressed subjective discomfort. Congenital cardiac anomalies were not diagnosed in any athlete. Also, cardiovascular abnormalities requiring additional evaluation, positive cardiac anamnesis, abnormal auscultatory findings, hypertension or abnormal ECG findings were not recognized in any patient. Moderate correlation was found among the left ventricle mass and heart rate (p<0.05). In order to minimalize or even possibly prevent the risk of sudden cardiac death it is necessary to establish an adequate strategy of cardiovascular screening of young athletes.

Increased rat neonatal activity influences adult cytokine levels and relative muscle mass

Little is known about the effect of physical activity in early life on subsequent growth and regulation of inflammation. We previously reported that exposure of muscles in growing rats to IL-6 results in decreased muscle growth apparently because of a state of resistance to growth factors such IGF-I and that running exercise could ameliorate this growth defect. Herein, we hypothesized that increased activity, for a brief period during neonatal life, would pattern the adult rat toward a less inflammatory phenotype. Neonatal rats were induced to move about their cage for brief periods from d 5 to d 15 postpartum. Additional groups were undisturbed controls (CONs) and handled (HAND). Subgroups of rats were sampled at the age of 30 and 65 d. Relative to CON and HAND groups, the neonatal exercise (EX) group demonstrated a decrease in circulating levels of TNFα, IL-6, and IL-1β in adulthood, primarily in male rats. In addition, adult male EX rats had lower body mass and increased skeletal muscle mass suggesting a leaner phenotype. The results of this study suggest that moderate increases in activity early in life can influence the adult toward a more healthy phenotype with regard to inflammatory mediators and relative muscle mass.