Higher body mass index may induce asthma among adolescents with pre-asthmatic symptoms: a prospective cohort study
1 Department of Public Health, China Medical University, Taichung City, Taiwan
2 Institute of Environmental Health, China Medical University, Taichung City, Taiwan
3 Department of Environmental and Occupational Health, School of Public Health, University of North Texas Health Science Centre, Fort Worth, Texas, USA
4 Department of Integrative Physiology and Cardiovascular Research Institute, University of North Texas Health Science Centre, Fort Worth, Texas, USA
5 Department of Health Risk Management, China Medical University, Taichung City, Taiwan
6 Department of Biostatistics and Bioinformatics, Tulane University, New Orleans, Louisiana, USA
7 Institute of Occupational Medicine and Industrial Hygiene and Department of Public Health, National Taiwan University College of Public Health, Taipei City, Taiwan
8 Department of Environmental and Occupational Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei City, Taiwan
9 Institute of Epidemiology and Preventive Medicine, National Taiwan University, Taipei City, Taiwan
BMC Public Health 2011, 11:542 doi:10.1186/1471-2458-11-542Published: 8 July 2011
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.
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.
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.
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.