Abstract P247: Multi-pollutant Mixtures and Digital Vascular Function in the Framingham Heart Study

Background: Studies of ambient air pollution and microvascular function have shown conflicting results. Aim: We investigated whether the association between fine particle mass with diameter ≤2.5μm (PM2.5) and microvascular function varies according to air pollution characteristics. Methods: We assessed baseline pulse amplitude and the ratio of fingertip pulse wave amplitude pre- and post- brachial artery occlusion (PAT ratio) in 1,365 participants of the Framingham Offspring and Third Generation Cohorts. We used K-means clustering to categorize mixtures of air pollutants into 5 distinct clusters of days with similar multi-pollutant profiles using elemental data and gases. We assessed the interaction between preceding day PM2.5 and cluster adjusting for season, meteorology and covariates. Results: We observed differences in associations between PM2.5 and baseline pulse amplitude by cluster (P=0.02 for interaction). On days with either low overall PM2.5 levels but dominated by road and traffic dust and a hi...