Body mass index and asthma severity in the National Asthma Survey

Thorax. 2008 Jan;63(1):14-20. doi: 10.1136/thx.2007.082784.

Abstract

Background: The association between obesity and asthma severity remains controversial and limited to small studies.

Methods: We determined the association of body mass index (BMI) and asthma severity in the National Asthma Survey. We included adults (age > or = 18 years) who self-reported symptoms of asthma in the past 5 years. A total of 3095 patients were divided into the following BMI categories: 1080 (35%) non-overweight (BMI < 25), 993 (32%) overweight (BMI > or = 25 and < 30) and 1022 (33%) obese (BMI > or = 30). Asthma severity measures included respiratory symptoms, healthcare utilisation, medication use, missed work days and the Global Initiative for Asthma (GINA) severity classification. Models were adjusted for: gender, race, age, education, income, employment status, smoking status, family history of asthma, state of residence and residence in a metropolitan statistical area.

Results: Compared with non-overweight subjects, obese subjects with asthma were more likely to report continuous symptoms (OR 1.66, 95% CI 1.09 to 2.54), miss more work days (OR 1.35, 95% CI 1.01 to 1.81), use short acting beta agonists (OR 1.36, 95% CI 1.06 to 1.75), use inhaled corticosteroids (OR 1.34, 95% CI 1.01 to 1.79) and use any controller medication according to GINA guidelines (OR 1.37, 95% CI 1.01 to 1.85). Also, obese respondents were less likely to be in asthma remission (OR 0.56, 95% CI 0.38 to 0.82) and were more likely to have severe persistent asthma (GINA IV) (OR 1.42, 95% CI 1.05 to 1.90).

Conclusions: In a large, diverse sample of adults with asthma, obesity was associated with measures of asthma severity after adjusting for potential confounders.

Publication types

  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Analysis of Variance
  • Asthma / physiopathology
  • Asthma / prevention & control*
  • Body Mass Index*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Obesity / complications
  • Obesity / physiopathology
  • Odds Ratio
  • Overweight / complications
  • Overweight / physiopathology