Protective role of dietary antioxidant intake on long-term effects of extreme PM _2.5 exposure on respiratory health

Objective

Evidence for the protective effects of dietary antioxidants on respiratory health following exposure to smoke from landscape fires is scarce. This study assessed whether the long-term respiratory effects of fine particulate matter (PM _2.5 ) from the 2014 Hazelwood coal mine fire were moderated by dietary antioxidants, 8.5 years later.

Methods

We conducted a cross-sectional analysis of data collected 8.5 years after the mine fire from 282 residents of Morwell (a highly exposed town adjacent to the mine) and 166 residents from the nearby unexposed town of Sale. Coal mine fire-related PM _2.5 was the primary exposure and meeting recommended dietary intake for antioxidants including vitamins (A, E and C), minerals (zinc, magnesium and selenium) and omega-3 fatty acids assessed through the Australian Eating Survey (AES) was the moderator. Respiratory symptoms were the primary outcome. Analyses used logistic regression models, adjusting for potential confounders.

Results

Vitamins A and E, magnesium, and zinc attenuated the association between fire-related PM _2.5 and prevalence of chronic cough; three of the four (except magnesium) attenuated the association between fire-related PM _2.5 and chronic phlegm. Omega-3 fatty acids attenuated the association between PM _2.5 and COPD.

Conclusion

Meeting recommended intakes of vitamins, A and E, magnesium and zinc may provide protection against the long-term adverse effects of exposure to particulate matter from other medium duration but extreme exposure events. Advocating incorporation of fruits and vegetables in daily diet could offer more than the conventional health benefits due to their high antioxidant content.

Highlights