Acute Pulmonary Function Response to Ozone in Young Adults As a Function of Body Mass Index

Abstract

Recent studies have shown enhanced responsiveness to ozone in obese mice. Adiposity has not been examined as a possible modulator of ozone response in humans. We therefore examined the relationship between body mass index and the acute spirometric response to ozone (O₃) exposure among 197 nonasthmatic young adults (aged 18–35 yr) studied in our human exposure facility from 1992 to 1998. Each subject had been exposed to 0.42 ppm O₃ for 1.5 h with intermittent exercise designed to produce a minute ventilation of 20 L/min/m² body surface area (BSA). Spirometry (pulmonary function) was measured pre- and immediately postexposure to determine acute ozone-induced changes. The decrement in forced expiratory volume in 1s (ΔFEV1) as percent of baseline was significantly correlated with BMI, r = −0.16, p = .03, with a slightly stronger correlation in women (n = 75), r = −0.22, p = .05, and no significant correlation in men. BMI had a greater range in women than in men in our study. In women greater ozone-induced decrements were seen in overweight (BMI > 25 kg/m²) than in normal weight (BMI 18.5 to 25 kg/m²), and in normal weight than in underweight (BMI < 18.5 kg/m²) for all spirometric variables considered (p trend ≤ .022). Although our population studied was predominantly normal weight, we found that higher body mass index may be a modest risk factor for adverse pulmonary effects associated with ozone exposure, especially for women.