Excessive TV viewing and cardiovascular disease risk factors in adolescents. The AVENA cross-sectional study.

BACKGROUND: Excessive television (TV) viewing might play an important role in the development of cardiovascular disease (CVD). The aim of this study was to examine the independent associations between TV viewing and CVD risk factors in adolescents. METHODS: A sample of 425 adolescents, aged 13- to 18.5-year-old, was included in this study. Body mass index (BMI), waist circumference (WC), glucose, total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, apolipoprotein (apo) A-1, apo B-100, and lipoprotein(a) levels were determined. A composite CVD risk score was computed based on age-, sex-, sexual maturation- and race-standardized triglycerides, HDL-cholesterol, LDL-cholesterol and glucose. TV viewing was self-reported. RESULTS: Two hundred and twenty-five adolescents (53%) who spent >3 hrs/day watching TV were considered as the "high TV viewing" group. Ninety-nine adolescents (23%) from the total sample were classified as overweight according to International age- and sex-specific BMI values. The high TV viewing group had significantly less favorable values of HDL-cholesterol, glucose, apo A1 and CVD score, independent of age, sex, sexual maturation, race and weight status. There was a significant interaction effect of TV viewing x weight status (P = 0.002) on WC, and the negative influence of TV viewing on WC persisted in the overweight group (P = 0.031) but was attenuated in non-overweight adolescents (P > 0.05). CONCLUSION: Excessive TV viewing seems to be related to an unfavorable CVD risk factors profile in adolescence. Reducing TV viewing in overweight adolescents might be beneficial to decrease abdominal body fat.

Television watching, videogames, and excess of body fat in Spanish adolescents: the AVENA study.

OBJECTIVE: We assessed the individual association of sedentary behaviors with the risk of overweight and excess body fat (overfat) in adolescents. METHODS: A representative sample (1960 subjects, 1012 males, age 13-18.5 y) of Spanish adolescents was studied within the framework of the Alimentación y Valoración del Estado Nutricional de los Adolescentes (AVENA) study. Television (TV) watching, videogame and computer usage, doing homework, and the way students got to school, physical activity, and socioeconomic status were analyzed. Anthropometrics were measured to describe overweight (International Obesity Task Force cutoffs for body mass index) and overfat (body fat percentage >85th percentile). RESULTS: When all subjects were considered as an entire group, the overweight risk increased by 15.8% (P < 0.05) per increasing hour of TV watching. The overweight risks decreased by 32.5% in females, 22% per increasing year of age, and 12.5% by increasing socioeconomic status by 1 U (all Ps < 0.05). The obesity risks decreased with age by 17.8% per year in males and 27.1% in females (both Ps < 0.05). The overfat risks increased by 26.8% and 9.4% per increasing hour of TV and weekend videogame usage, respectively (both Ps < 0.05). In males, the overfat risk increased by 21.5% per increasing hour in weekend videogame usage (P < 0.05). Each hour of TV use increased the overfat risks by 22% in males and 28.3% in females (both Ps < 0.05). CONCLUSIONS: Time spent watching TV increased the risk of overweight and obesity in Spanish adolescents, but the effect was influenced by age, sex, and socioeconomic status. Moreover, an excess of body fat was more directly explained by the time spent watching TV and playing videogames during the weekend.

Active commuting to school and cognitive performance in adolescents: the AVENA study.

OBJECTIVE: To examine the associations between active commuting to school and cognitive performance in adolescents. DESIGN: Cross-sectional study. SETTING: Five cities (Granada, Madrid, Murcia, Santander, and Zaragoza) in Spain. PARTICIPANTS: A total of 1700 adolescents (892 girls) aged 13 to 18.5 years. MAIN EXPOSURES: Mode and duration of transportation to school and participation in extracurricular physical activity were self-reported. MAIN OUTCOME MEASURES: Cognitive performance (verbal, numeric, and reasoning abilities and an overall score) was measured by the Spanish version of the SRA Test of Educational Ability. RESULTS: Active commuting to school was associated with better cognitive performance (all P < .05) in girls but not in boys, independent of potential confounders including participation in extracurricular physical activity. In addition, adolescent girls who spent more than 15 minutes actively commuting to school had better scores in 3 of the 4 cognitive performance variables (all P < .05) than those who spent less time actively commuting to school (≤15 minutes) as well as better scores in all of the cognitive performance variables (all P < .001) than girls inactively commuting. CONCLUSION: Active commuting to school and its duration may positively influence cognitive performance in adolescent girls.