Obesity and extent of emphysema depicted at CT

Clin Radiol. 2015 May;70(5):e14-9. doi: 10.1016/j.crad.2015.01.007. Epub 2015 Feb 19.

Abstract

Aim: To investigate the underlying relationship between obesity and the extent of emphysema depicted at CT.

Methods and materials: A dataset of 477 CT examinations was retrospectively collected from a study of chronic obstructive pulmonary disease (COPD). The low attenuation areas (LAAs; ≤950 HU) of the lungs were identified. The extent of emphysema (denoted as %LAA) was defined as the percentage of LAA divided by the lung volume. The association between log-transformed %LAA and body mass index (BMI) adjusted for age, sex, the forced expiratory volume in one second as percent predicted value (FEV1% predicted), and smoking history (pack years) was assessed using multiple linear regression analysis.

Results: After adjusting for age, gender, smoking history, and FEV1% predicted, BMI was negatively associated with severe emphysema in patients with COPD. Specifically, one unit increase in BMI is associated with a 0.93-fold change (95% CI: 0.91-0.96, p<0.001) in %LAA; the estimated %LAA for males was 1.75 (95% CI: 1.36-2.26, p<0.001) times that of females; per 10% increase in FEV1% predicated is associated with a 0.72-fold change (95% CI: 0.69-0.76, p<0.001) in %LAA.

Conclusion: Increasing obesity is negatively associated with severity of emphysema independent of gender, age, and smoking history.

Publication types

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

MeSH terms

  • Aged
  • Body Mass Index
  • Female
  • Humans
  • Male
  • Middle Aged
  • Obesity / complications*
  • Pennsylvania
  • Pulmonary Emphysema / complications*
  • Pulmonary Emphysema / diagnostic imaging*
  • Respiratory Function Tests
  • Risk Factors
  • Sex Factors
  • Surveys and Questionnaires
  • Tomography, X-Ray Computed / methods*