Overweight and changes in weight status during childhood in relation to asthma symptoms at 8 years of age

Background: Asthma may be more prevalent in overweight children. However, how early overweight and changes in weight status during childhood affect the asthma risk is unclear. Objectives: To investigate overweight and changes in overweight status in children age 1 to 8 years in relation to asthma symptoms in childhood. Methods: We studied 3756 children who participated in a large birth cohort study. The parents reported their children's weight and height, and wheeze, dyspnea, and prescription of inhaled corticosteroids in yearly questionnaires. Sensitization to inhalant allergens and bronchial hyperresponsiveness (BHR) were determined at 8 years. Results: At 8 years, 275 children (7.3%) wheezed, 361 (9.6%) had dyspnea, and 268 (7.1%) had a prescription of inhaled corticosteroids in the preceding year. Children who had a persistent high body mass index (BMI, weight/height(2)) during childhood or a high BMI at 6 to 7 years had a significantly increased risk of dyspnea (adjusted odds ratio, 1.68; 95% CI, 1.18-2.39, for a high BMI at 6-7 years) and measured BHR (adjusted odds ratio, 1.66; 95% CI, 1.10-2.52) at 8 years. Children with a high BMI at a young age, but who developed a normal BMI at 6 to 7 years, did not have an increased risk of dyspnea or BHR at 8 years. BMI was not associated with sensitization. Conclusion: Children with a current high BMI are at increased risk to have dyspnea and BHR at 8 years. A high BMI at an earlier age is not related to an increased risk if the child has become normal weight at 6 to 7 years. (J Allergy Clin Immunol 2009;123:1312-8.)