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

Abstract

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.

Introduction

Obesity in childhood and adolescence is becoming an increasing concern in America [1] and, more recently, in Europe [2], [3], [4]. For instance, the prevalence of overweight and obesity in Spanish adolescents has doubled in the past decennium and currently amounts to some 25% of males and 20% of females [4]. In this regard, obesity has been associated with sedentary lifestyle patterns in adolescent populations [5].

Although several environmental factors have been associated with childhood obesity [5], [6], such as low physical activity and eating disorders, the time spent watching television (TV) is the sedentary behavior most commonly studied [7]. It has been shown that the odds risk of being overweight is nearly five times greater in those subjects usually watching TV more than 5 h/d compared with those watching less than 1 h [8]. In addition, TV watching has been recently described as a predictor for childhood obesity in a Spanish case–control study [6]. This is of great concern because it has been reported that the number of children watching TV for more than 4 h/d is also increasing [9].

Recent data on the Spanish adolescent population suggest a greater risk of obesity with longer periods of TV watching [10] and data from Switzerland suggest that other sedentary activities, such as the use of electronic games, are also associated with obesity in children of that country [11]. It is not clear whether other sedentary activities are independently associated with obesity and it is not known if greater physical activity linked with usual activities such as active commuting to school could counterbalance the negative effect of TV and electronic device use. The aim of this study was to assess the individual risk for overweight and excess body fat of different sedentary behaviors (such as time spent watching TV or playing videogames), and whether physical activities such as active commuting to school could have a protective effect.