Protective role of dietary antioxidant intake on long-term effects of extreme PM2.5 exposure on respiratory health

OBJECTIVE: To test whether dietary antioxidants moderated effects of PM2.5 from coal mine fire smoke on respiratory symptoms. METHODS: We conducted cross-sectional analyses of diet and respiratory symptom data from 448 members of the Hazelwood Health Study Adult cohort. Individual-level exposure to PM2.5 from the 2014 coal mine fire was determined by combining modelled fire-related PM2.5 estimates and time-location diaries from the time of the fire. Data were evaluated using logistic regressions to evaluate associations between PM2.5 and respiratory symptoms and whether this was moderated by meeting recommended daily antioxidant intakes. RESULTS: Vitamins A and E, magnesium, and zinc attenuated the association between PM2.5 and chronic cough and (excluding magnesium) chronic phlegm. Omega-3 fatty acids attenuated the association between PM2.5 and COPD. CONCLUSION: Higher-quality diets may reduce harms due to smoke exposure from landscape fires.