Respiratory Responses to Ozone Exposure. MOSES (The Multicenter Ozone Study in Older Subjects)

Area of Science:

• Environmental Health
• Pulmonary Medicine
• Gerontology

Background:

• Acute respiratory effects of low-level ozone exposure are not well defined in older adults.
• The Multicenter Ozone Study in Older Subjects (MOSES) provided an opportunity to assess respiratory responses in this demographic.

Purpose of the Study:

• To evaluate the respiratory effects of controlled low-level ozone exposure in healthy older adults.
• To assess changes in lung function, airway inflammation markers, and airway epithelial injury.

Main Methods:

• A randomized crossover controlled exposure study involving 87 healthy older adults (mean age ~60 years).
• Participants were exposed to 0, 70, and 120 parts per billion (ppb) ozone for 3 hours with intermittent exercise.
• Outcome measures included spirometry, sputum inflammatory markers, and plasma club cell protein-16 (CC16).

Main Results:

• Ozone exposure reduced lung function (FEV1 and FVC) in a concentration-dependent manner, with effects persisting for 22 hours.
• Plasma CC16 levels, a marker of airway epithelial injury, increased with ozone concentration.
• Sputum neutrophils showed a marginally significant increase, but key proinflammatory cytokines were not significantly affected.

Conclusions:

• Exposure to near-ambient ozone levels induces measurable lung function impairment, airway injury, and inflammation in healthy older adults.
• These findings highlight the respiratory risks associated with ozone pollution in the aging population.