Bronchoconstriction Provoked by Exercise in a High-Particulate-Matter Environment is Attenuated by Montelukast

Abstract

Airborne ultrafine and fine particulate matter (PM₁ from fossil-fueled internal combustion engines may cause abnormal airway narrowing. Because of high PM₁ exposure from ice resurfacing machines, the ice-rink athlete is especially vulnerable to PM₁ toxicity. The purpose of this study was to evaluate protection by a single dose of montelukast in college ice hockey players following PM₁ exposure exercise. Nine male ice hockey players (age 19.3 ± 1.22 yr) performed 4 randomized, double-blinded, high-intensity, 6-min cycle ergometer trials in low [PM₁] (2260 ± 500 particles/cm³) and high [PM₁] (348,600 ± 121,600 particles/cm³) after placebo or montelukast. Pre- and postspirometry showed similar peak FEV₁ (forced expiratory volume in 1 s) falls between placebo and montelukast after low [PM₁] trials (14.5 ± 18.06 vs. 9.5 ± 11.75% of baseline, respectively). Peak FEV₁ falls after high [PM₁] trials were greater for placebo than for montelukast (17.3 ± 9.79% vs. 1.7 ± 5.77% of baseline; p < .0001). High [PM₁] FEV₁ fall after exercise following montelukast ingestion was less than after exercise following placebo ingestion under high and low [PM₁] conditions and after exercise following montelukast ingestion under low [PM₁] conditions at 5, 10, and 15 min postchallenge (p < .004, .0006, .009, respectively). Montelukast provided greater protection against bronchoconstriction after exercise during high [PM₁] than low [PM₁] exposure (∼90% vs. ∼35%), suggesting that bronchoconstriction from PM₁ exposure is predominately leukotriene mediated. The precise mechanism of airborne PM₁-induced leukotriene-mediated airway narrowing remains unclear.

Notes

The authors thank the subjects who volunteered for this study. Supported by Merck and Co., Inc., grant SING-US-63-01. Montelukast and placebo were a gift from Merck and Co.