title: Higher body mass index may induce asthma among adolescents with pre-asthmatic symptoms: a prospective cohort study.
abstract: BACKGROUND
  Limited studies have prospectively examined the role of body mass index (BMI) as a major risk factor for asthma during adolescence. This study investigates whether BMI is associated with increased risk of developing physician-diagnosed asthma during 12-month follow-up among adolescents with undiagnosed asthma-like symptoms at baseline.
  
  
  METHODS
  A total of 4,052 adolescents with undiagnosed asthma-like symptoms at baseline were re-examined after a 12-month follow-up. Asthma cases were considered confirmed only after diagnosis by a physician based on the New England core and International Study of Asthma and Allergies in Childhood (ISAAC) criteria video questionnaires, and accompanying pulmonary function tests. Logistic regression analyses were used to evaluate the relationship of BMI and the risk of acquiring asthma.
  
  
  RESULTS
  The results indicated that girls with higher BMI were at an increased risk of developing asthma during the 12-month follow-up. The odds ratios for girls developing physician-diagnosed asthma were 1.75 (95% CI = 1.18-2.61) and 1.12 (95% CI = 0.76-1.67), respectively, for overweight and obesity as compared to the normal weight reference group after adjustment for other covariates. A similar relationship was not observed for overweight and obese boys who were also significantly more active than their female counterparts.
  
  
  CONCLUSIONS
  Increased BMI exaggerates the risk of acquiring asthma in symptomatic adolescent females but not in adolescent males. Thus, gender is an important modifier of BMI-related asthma risk. Additional research will be required to determine whether the increased asthma risk results from genetic, physiological or behavioural differences.
authors: Department of Public Health, China Medical University, Taichung City, Taiwan. whocmu@gmail.com
authors: Wen-Chao
authors: WC
authors: Ho
authors: Yu-Sheng
authors: YS
authors: Lin
authors: James L
authors: JL
authors: Caffrey
authors: Meng-Hung
authors: MH
authors: Lin
authors: Hui-Tsung
authors: HT
authors: Hsu
authors: Leann
authors: L
authors: Myers
authors: Pau-Chung
authors: PC
authors: Chen
authors: Ruey-Shiung
authors: RS
authors: Lin
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*; D015992:Body Mass Index; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D011446:Prospective Studies; D018570:Risk Assessment; D011795:Surveys and Questionnaires; D013624:Taiwan