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Chest. 2007 Dec;132(6):1890-7. Epub 2007 Oct 9.

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

Author information

1
Department of Environmental Health, Harvard School of Public Health, Landmark Center West, 415, 401 Park Dr, Boston, MA 02215, USA. sackerma@hsph.harvard.edu

Abstract

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.

PMID:
17925423
DOI:
10.1378/chest.07-1126
[Indexed for MEDLINE]

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