Late Breaking Abstract - Effects of ultrafine particles on respiratory health in adults

Background and Aim: The contribution of long-term exposure to ultrafine particles (UFP) to chronic respiratory disease is unclear. We compared the effect of UFP on the incidence of chronic obstructive pulmonary disease (COPD) to the effect of other size fractions of particulate matter like PM2.5 and PM10. Methods: This study builds on the EPIC-NL cohort, in which 35,000 Dutch adults were enrolled in 90’s and followed up until 2011. Exposure to each size fraction of particulate matter was estimated using a National Land-Use Regression Model. Demographics of participants and potential confounders were obtained from questionnaires and from area-based spatial predictors. Incidence of COPD was determined using the first COPD hospital admission from Hospital Discharge Registry. For each air pollutant, a Multivariable Cox proportional hazard regression model was used to assess its association with COPD incidence. Results: At baseline, participants were mean (SD) age of 51(11) years, 24% were male, and had BMI of 25(4). Median (IQR) exposure was 10,760 (2912) UFP particles/cm3, 17(0.6) PM2.5 μg/m3, and 25(1.7) PM10 μg/m3. During follow-up, 451(1.3%) participants developed COPD. There were no significant associations between PM and UFP in the main model. The risk of COPD admission was (HR 0.98, 95%CI 0.87–1.10; p=0.69) for UFP, (HR 0.92, 95%CI 0.83–1.03; p=0.14) for PM2.5, and (HR 0.85, 95%CI 0.75–0.96; p=0.01) for PM10. Conclusions: This study is the first report on the long-term effects of UFPs exposure on COPD incidence. Our findings do not support the hypothesis that the particle size of air pollutants is relevant in terms of the potential to cause respiratory disease.