The Association Between BMI, Vigorous Physical Activity and Television Viewing and the Risk of Symptoms of Asthma, Rhinoconjunctivitis and Eczema in Children and Adolescents: ISAAC Phase Three
PURPOSE OF THE STUDY.
To determine if a relationship exists between body mass index (BMI), vigorous physical activity, and television viewing, with symptoms of eczema, rhinoconjunctivitis, and asthma.
Data from 76 164 children aged 6 to 7 years (29 centers; 17 countries) and 201 370 adolescents aged 13 to 14 years (73 centers; 35 countries) was analyzed as part of the International Study of Asthma and Allergies in Childhood (ISAAC) Phase III study, a multicenter, multicountry, cross-sectional population chosen from a random sample of schools in a defined geographical area.
Parents or guardians (for children aged 6–7 years, focusing on height and weight, symptoms of asthma, rhinoconjunctivitis, eczema symptoms, vigorous physical activity, and television viewing) completed questionnaires characterizing asthma, rhinitis, and eczema. Adolescents self-completed the questionnaires. Vigorous physical activity was determined by how many times per week the patient breathes hard with exercise. Television viewing was assessed by how many hours were watched per week. In most centers, the individual completing the questionnaire reported height and weight.
There was a dose–effect relationship seen with the risk of asthma symptoms and eczema in patients who were obese or overweight compared with those children who were underweight. This finding was not seen for rhinoconjunctivitis. Vigorous physical activity correlated with symptoms of asthma, rhinoconjunctivitis, and eczema in adolescents but not in young children. Viewing ≥5 hours of television a day was associated with an increased risk of symptoms of asthma, rhinoconjunctivitis, and eczema in adolescents compared with watching <1 hour. In the 6- to 7-year-old group, television watching for ≥5 hours daily was associated with increased asthma symptoms.
There is a link between overweight/obesity and symptoms of asthma. Significant associations are also seen for symptoms of eczema but not rhinoconjunctivitis. These complex relationships are affected by lifestyle activity levels, with sedentary behavior having more of a negative impact.
Although there are several limitations to this study based on the reliance of parental and self-reported information including height and weight, the study size and multinational nature of this study is impressive. This study adds to the increasing body of evidence indicating obesity as a risk factor for symptoms of asthma. In addition, the American Academy of Pediatrics’ guidelines for the prevention of childhood obesity suggest limiting sedentary time/screen time to <2 hours per day, which is clearly supported by this study.
- Copyright © 2013 by the American Academy of Pediatrics