Long-Term Air Pollution Exposure, Plant-based Diet, and Asthma Exacerbations in the Nurses' Health Study II

Area of Science:

• Environmental Health
• Epidemiology
• Respiratory Medicine

Background:

• Short-term air pollution exposure is known to worsen asthma.
• The long-term effects of air pollution on asthma exacerbations and potential dietary mitigation remain unclear.

Purpose of the Study:

• To investigate the association between long-term exposure to ambient air pollution (PM2.5, NO2, O3) and asthma exacerbations.
• To determine if a plant-based diet modifies these associations.

Main Methods:

• Utilized data from the Nurses' Health Study II (1997-2014) with 4326 women with asthma.
• Estimated 48-month average exposures to PM2.5, NO2, and O3 using spatiotemporal models.
• Assessed plant-based diet index (PDI) and asthma exacerbations, analyzing interactions using logistic regression and GEE.

Main Results:

• Increased exposure to PM2.5 and NO2 was associated with higher odds of asthma exacerbation in single-pollutant models.
• In multi-pollutant models, NO2 exposure remained significantly associated with increased asthma exacerbation risk.
• No significant interaction was found between air pollutants and PDI scores on asthma exacerbations.

Conclusions:

• Long-term exposure to ambient NO2 and PM2.5, even at low levels, may elevate asthma exacerbation risk in women.
• A plant-based diet, as measured, did not attenuate the risk associated with these air pollutants.
• Further research is needed on long-term inhaled pollutant effects and personal risk reduction strategies.