A 10-Month Physical Activity Intervention Improves Body Composition in Young Black Boys

Objective. To determine if a 10-month after-school physical activity (PA) intervention could prevent deleterious changes in body composition and cardiovascular (CV) fitness in young black boys. Methods. Following baseline measures, 106 boys (8–12 yrs) were randomized to either a control group or an intervention group, further divided into attenders (ATT) and nonattenders (NATT), participating in ≥60% or <60% of the intervention, respectively. The daily intervention consisted of skills development (25 min), vigorous PA (VPA, 35 min), and strengthening/stretching (20 min) components. Body composition was measured by dual-energy X-ray absorptiometry. Results. Following the intervention, the ATT exhibited an increase in moderate-to-vigorous PA and a significant reduction in BMI, fat mass, and %BF compared to the control group. A significant association among the intervention energy expenditure and changes in body composition and CV fitness was observed only in the ATT group. Conclusion. An after-school PA program of sufficient length and intensity can promote healthy changes in body composition and fitness levels in black boys who attend at least 3 days/week

Relations of diet and physical activity to bone mass and height in black and white adolescents

Because the development of healthy bodies during the years of growth has life-long health consequences, it is important to understand the early influences of diet and physical activity (PA). One way to generate hypotheses concerning such influences is to conduct cross-sectional studies of how diet and PA are related to different components of body composition. The subjects were 660 black and white adolescents. Total body bone mineral content (BMC) was measured with dual-energy X-ray absorptiometry; free-living diet and PA were assessed with 4–7 separate 24-h recalls. The main dietary variables investigated were: total energy intake, macronutrient distribution (%), dairy servings, vitamin D, and calcium. The main PA variables were hours of moderate PA (3–6 METs) and vigorous PA (>6 METs). BMC was higher in blacks than in whites (P<0.01) and it increased more in boys than in girls (age by sex interaction) as age increased (P<0.01). After adjustment for age, race and sex, higher levels of BMC were associated with higher levels of energy intake, dairy servings, calcium, vitamin D, and vigorous PA (all P 's<0.05). In the multivariable model, significant and independent proportions of the variance in BMC were explained by race, the age by sex interaction, calcium, and vigorous PA (all P 's<0.01). When height was used as the outcome variable, similar diet results were obtained; however, there was a sex by vigorous PA interaction, such that vigorous PA was associated with height only in the girls. These data are consistent with the hypothesis that the bone mass and height of growing youths are positively influenced by higher dietary intake of energy and dairy foods, along with sufficient amounts of vigorous PA. This hypothesis needs to be tested in randomized controlled trials

Nonlinear Relationship between Birth Weight and Visceral Fat in Adolescents

To determine the association of birth weight with abdominal fat distribution and markers known to increase risk for cardiovascular disease and type 2 diabetes in adolescents

FTO variant rs9939609 is associated with body mass index and waist circumference, but not with energy intake or physical activity in European- and African-American youth

<p>Abstract</p> <p>Background</p> <p>Genome-wide association studies found common variants in the fat mass and obesity-associated (<it>FTO</it>) gene associated with adiposity in Caucasians and Asians but the association was not confirmed in African populations. Association of <it>FTO </it>variants with insulin resistance and energy intake showed inconsistent results in previous studies. This study aimed to assess the influence of <it>FTO </it>variant rs9939609 on adiposity, insulin resistance, energy intake and physical activity in European - (EA) and African-American (AA) youth.</p> <p>Methods</p> <p>We conducted a cross-sectional study in EA and AA youths. One thousand, nine hundred and seventy-eight youths (48.2% EAs, 47.1% male, mean age 16.5 years) had measures of anthropometry. Percent body fat (%BF) was measured by dual-energy X-ray absorptiometry, visceral adipose tissue (VAT) and subcutaneous abdominal adipose tissue (SAAT) by magnetic resonance imaging. Energy intake and physical activity were based on self report from up to 7 24-hour recalls. Physical activity was also measured by accelerometry.</p> <p>Results</p> <p><it>FTO </it>rs9939609 was significantly associated with body mass index (BMI) (<it>P </it>= 0.01), weight (<it>P </it>= 0.03) and waist circumference (<it>P </it>= 0.04), with per-allele effects of 0.4 kg/m², 1.3 kg and 0.8 cm, respectively. No significant association was found between rs9939609 and %BF, VAT, SAAT or insulin resistance (<it>P </it>> 0.05), or between rs9939609 and energy intake or vigorous physical activity (<it>P </it>> 0.05). No significant interactions of rs9939609 with ethnicity, gender, energy intake or physical activity were observed (<it>P </it>> 0.05).</p> <p>Conclusions</p> <p>The <it>FTO </it>variant rs9939609 is modestly associated with BMI and waist circumference, but not with energy intake or physical activity. Moreover, these effects were similar for EAs and AAs. Improved understanding of the effect of the <it>FTO </it>variant will offer new insights into the etiology of excess adiposity.</p

Adolescent Obesity, Bone Mass, and Cardiometabolic Risk Factors

To compare bone mass between overweight adolescents with and without cardiometabolic risk factors (CMR). Associations of bone mass with CMR and adiposity were also determined

The Impact of a 3-Year After-School Obesity Prevention Program in Elementary School Children

Children tend to be sedentary during the after-school hours, and this has deleterious effects on their health. The objective of the present study was to determine the effects of a 3-year after-school physical activity (PA) program, without restriction of dietary energy intake, on percent body fat (%BF), cardiorespiratory fitness (CRF), and cardiometabolic markers in children

Greater Fructose Consumption Is Associated with Cardiometabolic Risk Markers and Visceral Adiposity in Adolescents

Though adolescents consume more fructose than any other age group, the relationship between fructose consumption and markers of cardiometabolic risk has not been established in this population. We determined associations of total fructose intake (free fructose plus one-half the intake of free sucrose) with cardiometabolic risk factors and type of adiposity in 559 adolescents aged 14–18 y. Fasting blood samples were measured for glucose, insulin, lipids, adiponectin, and C-reactive protein. Diet was assessed with 4–7 24-h recalls and physical activity (PA) was determined by accelerometry. Fat-free soft tissue (FFST) mass and fat mass were measured by DXA. The s.c. abdominal adipose tissue (SAAT) and visceral adipose tissue (VAT) were assessed using MRI. Multiple linear regression, adjusting for age, sex, race, Tanner stage, FFST mass, fat mass, PA, energy intake, fiber intake, and socioeconomic status, revealed that fructose intake was associated with VAT (β = 0.13; P = 0.03) but not SAAT (P = 0.15). Significant linear upward trends across tertiles of fructose intake were observed for systolic blood pressure, fasting glucose, HOMA-IR, and C-reactive protein after adjusting for the same covariates (all P-trend 0.05). In adolescents, higher fructose consumption is associated with multiple markers of cardiometabolic risk, but it appears that these relationships are mediated by visceral obesity

Clinical Study Cardiometabolic Biomarkers in Young Black Girls: Relations to Body Fatness and Aerobic Fitness, and Effects of a Randomized Physical Activity Trial

There is little evidence from randomized trials showing that physical activity alone influences biomarker profiles in youths. This study tested two hypotheses: (i) that elevated body fatness and poor fitness would be associated with unfavorable levels of cardiometabolic biomarkers in 8-12-y-old black girls (n = 242) and (ii) that a 10-mo PA intervention would have favorable effects on the fatness-related cardiometabolic biomarkers. At baseline, all fatness indices (i.e., percent body fat, visceral adipose tissue, BMI, and waist circumference) were significantly (P &lt; 0.05) associated with unfavorable levels of insulin, glucose, systolic BP, diastolic BP, triglycerides, C-reactive protein (CRP), and fibrinogen. Aerobic fitness was significantly (P &lt; 0.05) associated with favorable levels of insulin, CRP, fibrinogen, and HDL 2 . The PA intervention had significant and favorable effects on fitness, fatness, and two biomarkers-resting heart rate and LDL cholesterol. More research is needed to clarify what types of interventions can enhance the cardiometabolic health of youths

Validation of the Physical Activity Questionnaire for Older Children in Children of Different Races

The Physical Activity Questionnaire for Older Children (PAQ-C) is a validated self-report measure of physical activity widely used to assess physical activity in children (8-14 years of age). To date, however, the instrument has been validated in largely White Canadian samples. The purpose of the present article is to determine the pscyhometric properties of the PAQ-C for African American, European American, and Hispanic children. Two studies were conducted in which independent samples were administered the PAQ-C, along with varying indices of cardiovascular fitness, fatness, and psychological measures related to physical activity. Results showed that the reliability and validity of the PAQ-C varied by race and that modifications might be necessary

A Genome-Wide Methylation Study of Severe Vitamin D Deficiency in African American Adolescents

To test the hypothesis that changes in DNA methylation are involved in vitamin D deficiency–related immune cell regulation using an unbiased genome-wide approach combined with a genomic and epigenomic integrative approach