RESUMEN
PURPOSE: We aimed to determine whether 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 were used to address our objectives (N = 11,115; 6-18 yr; 51% female). We calculated age- and gender-specific BMI and 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 indicates 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.
Asunto(s)
Ejercicio Físico , Obesidad Infantil/epidemiología , Conducta Sedentaria , Acelerometría , Adolescente , Australia/epidemiología , Índice de Masa Corporal , Brasil/epidemiología , Niño , Metabolismo Energético , Europa (Continente)/epidemiología , Femenino , Humanos , Masculino , Obesidad Infantil/prevención & control , Prevalencia , Análisis de Regresión , Televisión , Estados Unidos/epidemiología , Circunferencia de la CinturaRESUMEN
BACKGROUND: Investigating socioeconomic variation in physical activity (PA) and sedentary time is important as it may represent a pathway by which socioeconomic position (SEP) leads to ill health. Findings on the association between children's SEP and objectively assessed PA and/or sedentary time are mixed, and few studies have included international samples. OBJECTIVE: Examine the associations between maternal education and adolescent's objectively assessed PA and sedentary time. METHODS: This is an observational study of 12â 770 adolescents (10-18â years) pooled from 10 studies from Europe, Australia, Brazil and the USA. Original PA data were collected between 1997 and 2009. The associations between maternal education and accelerometer variables were examined using robust multivariable regression, adjusted for a priori confounders (ie, body mass index, monitor wear time, season, age and sex) and regression coefficients combined across studies using random effects meta-analyses. Analyses were conducted in March 2014. RESULTS: Adolescents of university educated mothers spent more time sedentary (9.5â min/day, p=0.005) and less time in light activity (10â min/day, p<0.001) compared with adolescents of high school educated mothers. Pooled analysis across two studies from Brazil and Portugal (analysed separately because of the different coding of maternal education) showed that children of higher educated mothers (tertiary vs primary/secondary) spent less time in moderate to vigorous PA (MVPA) (6.6â min/day, p=0.001) and in light PA (39.2â min/day: p<0.001), and more time sedentary (45.9â min/day, p<0.001). CONCLUSIONS: Across a number of international samples, adolescents of mothers with lower education may not be at a disadvantage in terms of overall objectively measured PA.
Asunto(s)
Escolaridad , Ejercicio Físico , Madres , Conducta Sedentaria , Acelerometría , Adolescente , Australia , Brasil , Niño , Estudios Transversales , Europa (Continente) , Femenino , Humanos , Masculino , Actividad Motora , Análisis Multivariante , Análisis de Regresión , Estados UnidosRESUMEN
OBJECTIVE: To examine the associations of adiposity and aerobic fitness with executive function and math performance in Danish adolescents. STUDY DESIGN: Cross-sectional analyses were conducted with data on 525 adolescents attending sixth and seventh grades from 14 schools in the 5 main regions of Denmark. A modified Eriksen flanker task was used to assess inhibitory control, a key aspect of executive function. Academic performance was assessed by a customized math test. Aerobic fitness was assessed by an intermittent shuttle-run test (Andersen test). RESULTS: Body mass index (BMI) was negatively associated with accuracy on incongruent trials during the flanker task (P = .005). A higher BMI was associated with a larger accuracy interference score (P = .01). Similarly, waist circumference (WC) was negatively associated with accuracy on incongruent trials (P = .008). A higher WC was associated with a larger reaction time (RT) interference score (P = .02) and accuracy interference score (P = .009). Higher aerobic fitness was associated with a faster RT on congruent trials (P = .009) and incongruent trials (P = .003). Higher aerobic fitness was associated with a smaller RT interference score (P = .04). Aerobic fitness was positively associated with math score (P < .001). BMI and WC were not associated with math score (P > .05). CONCLUSIONS: These results suggest that aerobic fitness is positively associated with both inhibitory control and math performance in adolescents. Adiposity is negatively associated with inhibitory control in adolescents. Adiposity is not associated with math performance.