Physical Activity and Pediatric Obesity

Abstract

Purpose We aimed to determine if moderate-to-vigorous physical activity (MVPA) and sedentary behavior (SB) were independently associated with body mass index (BMI) and waist circumference (WC) in children and adolescents. Methods Data from the International Children’s Accelerometry Database (ICAD) were used to address our objectives (N=11,115; 6-18y; 51% female). We calculated age and gender specific body mass index (BMI) and waist circumference (WC) Z-scores and used accelerometry to estimate MVPA and total SB. Self-reported television viewing was used as a measure of leisure time SB. Quantile regression was used to analyze the data. Results MVPA and total SB were associated with lower and higher BMI and WC Z-scores, respectively. These associations were strongest at the higher percentiles of the Z-score distributions. After including MVPA and total SB in the same model the MVPA associations remained, but the SB associations were no longer present. For example, each additional hour per day of MVPA was not associated with BMI Z-score at the 10th percentile (b=-0.02, P=0.170), but was associated with lower BMI Z-score at the 50th (b=-0.19, P<0.001) and 90th percentiles (b=-0.41, P<0.001). More television viewing was associated with higher BMI and WC and the associations were strongest at the higher percentiles of the Z-score distributions, with adjustment for MVPA and total SB. Conclusions Our observation of stronger associations at the higher percentiles indicate that increasing MVPA and decreasing television viewing at the population-level could shift the upper tails of the BMI and WC frequency distributions to lower values, thereby lowering the number of children and adolescents classified as obese.

Added sugar and trans fatty acid intake and sedentary behavior were associated with excess total‐body and central adiposity in children and adolescents with congenital heart disease

“…Our results showed that sedentary behavior was positively associated with central adiposity. In agreement with our results, a previous cross‐sectional study found that each increment in 1 hour of sedentary behaviors was associated with 0.05 cm higher waist circumference in healthy children and adolescents from Europe, the United States of American, Brazil, and Australia …”

Physical Activity, Not Sedentary Time, Predicts Dual-Energy X-ray Absorptiometry–measured Adiposity Age 5 to 19 Years

“…In general, our findings support the results of other recent empirical studies by Katzmarzyk and colleagues (16), Mitchell and colleagues (23), and Riddoch and colleagues (28) as well as a systematic review by Kelley and colleagues (17). When coupled with these reports, our study suggests that the correct metabolic target for reducing the incidence of childhood obesity is at least moderate-intensity PA. We speculate that MVPA involves different physiological mechanisms than LPA (9,25).…”

“…Similar to our findings, Mitchell et al also concluded that TV was positively associated with adiposity, independently of SED and MVPA (23). It is possible that self-reported TV viewing better represents true sedentary behavior than low accelerometer activity counts.…”

“…Physical activity was represented as two intensity bands based on metabolic demand: light and moderate or vigorous. We differentiated between sedentary time and TV viewing time because current research suggests that TV time has an independent role in childhood obesity (3,23). Adiposity was represented by two variables: total adiposity and visceral adiposity.…”

“…In a large cross-sectional study using data of 11,115 children and adolescents from the International Children’s Accelerometry Database (ICAD), Mitchell and colleagues concluded that objectively measured MVPA was independently associated with lower BMI and waist circumference z-scores. The ICAD study also reported that TV was independently associated with higher BMI and waist circumference z-scores while total SED was not (23). Similarly, in their recent review article, Ekelund and colleagues reported that, out of 9 cohort studies that examined the relationship between SED and adiposity in youth, 8 studies indicated that SED and adiposity were not significantly related after controlling for MVPA (5).…”