Association between asthma and physical activity in Korean adolescents: the 3rd Korea Youth Risk Behavior Web-based Survey (KYRBWS-III).

BACKGROUND Asthma is the leading chronic illness among children and adolescents in several nations. This study investigated the association between asthma and physical activity (PA). METHODS The findings in this study are based on the data obtained from the 2007 3rd Korea Youth Risk Behavior Web-Based Survey (KYRBWS-III), a cross-sectional survey of health-risk behaviours among a representative sample of Korean middle- and high-school students aged 13-18 years. This survey is conducted annually by the Korea Centers for Disease Control and Prevention. The 72 943 study subjects were selected using the complex sampling design of the survey. The association between asthma and PA was assessed by conducting multiple logistic regression analyses of the data by using the statistical software SPSS 17.0 Complex Sample. RESULTS Compared with the adolescents without current asthma, significantly fewer adolescents with current asthma had a sedentary time of 3 h or less per day (odds ratio, 0.86; 95% confidence interval, 0.75-0.97). Sedentary time was defined as time spent watching television, surfing the Internet, or playing computer games and excluded the time spent doing homework or study during leisure time. The analysis was adjusted for age, gender, family affluence level (FAL), obesity, allergic rhinitis, atopy and smoking. With regard to participation in adequate vigorous or moderate PA, strengthening exercise or physical education class, no significant differences were found between the adolescent students with current asthma and those without current asthma. In addition, it was found that all PA had no significant differences in their effects on asthma severity (medication, inability to work and absence from school). CONCLUSION Our results show that the amount of sedentary time influenced asthma prevalence; however, PA did not influence asthma prevalence in Korean adolescents.