Evaluating Potential Response-Modifying Factors for Associations between Ozone and Health Outcomes: A Weight-of-Evidence Approach
Epidemiologic and experimental studies have demonstrated a variety of health effects in response to ozone (O3) exposure. Studies have demonstrated that some populations may be at increased risk of O3-related health effects. Objectives: To identify populations and lifestages potentially at increased risk of O3-related health effects by applying a novel strength of evidence approach for identifying and classifying factors associated with increased risk. Methods: Epidemiologic, experimental, and exposure science studies of populations potentially at increased risk of O3-related health effects were identified and evidence was integrated across disciplines to evaluate consistency, coherence, and biological plausibility of effects. The factors identified were then classified using a strength of evidence approach to conclude whether a population or lifestage is at increased risk of O3-related health effects. Discussion: We found “adequate” evidence that populations with certain genotypes, different lifestages, populations with preexisting asthma, populations with reduced intake of certain nutrients, and outdoor workers are at increased risk of O3 related health effects. Additionally, we identified other factors (i.e., sex, SES, and obesity) for which there was “suggestive” evidence of increased risk of O3-related health effects. Conclusions: We identified a diverse group of factors that potentially result in an increased risk of O3-related health effects. Additionally, a novel strength of evidence framework was introduced that allows researchers to characterize whether populations are at increased risk of health effects due to environmental exposures.