The association of BMI and sedentary time with respiratory symptoms and asthma in 5th grade schoolchildren in Kaohsiung, Taiwan.

This study aimed to evaluate the association of body fatness and sedentary status with asthma and respiratory symptoms in schoolchildren in Kaohsiung, Taiwan. A questionnaire study elicited episodes of respiratory symptoms and data on lifestyle and anthropometric parameters in 1329 5th grade schoolchildren. Results showed that 12.4% of boys and 9.5% of girls had physician-diagnosed asthma, whereas 15.1% of boys and 12.4% of girls had suspected asthma. Significantly greater proportions of boys had non-exercise-induced respiratory symptoms than girls (p < 0.05). The number of respiratory symptoms was positively correlated with TV-watching time per day and self-reported sedentary time per weekend-day in girls (p < 0.05). Underweight was positively associated with one of the seven respiratory symptoms in girls (p < 0.05). At risk of overweight was positively associated with two of the seven respiratory symptoms in boys and one of the seven respiratory symptoms in girls (all p < 0.05). The risk of having physician-diagnosed asthma and suspected asthma increased 93% and 72%, respectively, in schoolchildren at risk of overweight (p < 0.05). Overweight was associated with a 78% increase in physician-diagnosed asthma (adjusted odd ratio (aOR) = 1.78, 95% CI = 1.08-2.91, p < 0.05). Higher sedentary time was significantly associated with more occurrences of one of the seven respiratory symptoms in girls (aOR = 1.05, 95% CI = 1.00-1.11, p < 0.05). Higher body mass index (BMI) was significantly correlated with longer TV-watching time per day in girls and longer self-reported sedentary time per weekday in boys (p < 0.05). In summary, schoolchildren who are at risk of overweight or overweight and/or have more sedentary time have increased risk of respiratory symptoms and asthma. Weight and sedentary statuses of schoolchildren can affect their respiratory health.