Ozone exposure and lung function: effect modified by obesity and airways hyperresponsiveness in the VA normative aging study

Chest. 2007 Dec;132(6):1890-7. doi: 10.1378/chest.07-1126. Epub 2007 Oct 9.


Background: Ozone has heterogeneous effects on lung function. We investigated whether obesity and airways hyperresponsiveness (AHR) modify the acute effects of ozone on lung function in the elderly.

Methods: We studied 904 elderly men from the Normative Aging Study whose lung function (FVC, FEV1) was measured approximately every 3 years from 1995 to 2005. We defined obesity as a body mass index of at least 30 kg/m2. Using a standardized methacholine challenge test, we defined AHR as a FEV1 decline of 20% after inhalation of a cumulative dosage of 0 to 8.58 micromol of methacholine. Ambient ozone in the Greater Boston area was measured continuously. We estimated effects using mixed linear models, adjusting for known confounders.

Results: An increase in ozone of 15 parts per billion during the previous 48 h was associated with a greater decline in FEV1 in the obese (-2.07%; 95% confidence interval [CI], -3.25 to -0.89%) than in the nonobese (-0.96%; 95% CI, -1.70 to - 0.20%). The same exposure was also associated with a greater decline in FEV1 for those with AHR (-3.07%; 95% CI, -4.75 to -1.36%) compared to those without AHR (-1.32%; 95% CI, -2.06 to -0.57%). A three-way interaction trend test demonstrated a multiplicative effect of those two risk factors (p < 0.001). We found similar associations for FVC.

Conclusions: Our results indicate that both obesity and AHR modify the acute effect of ozone on lung function in the elderly, with evidence of interaction between AHR and obesity that causes a greater than additive effect.

Publication types

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

MeSH terms

  • Aged
  • Aging / physiology
  • Bronchial Hyperreactivity / complications*
  • Bronchial Provocation Tests
  • Environmental Exposure / analysis*
  • Forced Expiratory Volume / drug effects*
  • Forced Expiratory Volume / physiology
  • Humans
  • Likelihood Functions
  • Male
  • Methacholine Chloride
  • Obesity / complications*
  • Ozone / adverse effects*
  • Ozone / analysis
  • Regression Analysis
  • Spirometry
  • United States
  • Veterans
  • Vital Capacity / drug effects*
  • Vital Capacity / physiology


  • Methacholine Chloride
  • Ozone