Air Pollution Exposure clinical trials

Reducing Air Pollution to Lower Blood Pressure

Fine particulate matter <2.5 μm (PM2.5) air pollution is the fifth leading risk factor for global mortality. Mitigating the clinically significant blood pressure (BP) elevation from air pollution by reducing PM2.5 exposure will likely contribute to the reduction in cardiovascular disease-related mortality. Twin epidemics of air pollution and high BP converge in underserved urban communities (i.e., Detroit) and warrant immediate attention. Prior studies with short duration (a few days) showed indoor portable air cleaners (PACs) are a novel approach to reduce the health burden of both high BP and PM2.5. Trials over several weeks employing remote technologies with a large sample size of patients residing in their own homes in vulnerable urban communities are needed to demonstrate if the BP-reduction from PAC usage is sustainable in real-world settings. The investigators' specific aims are to 1) determine if compared to sham, active PAC use during 3 weeks can provide sustained reductions in home BP levels by reducing personal-level PM2.5 air pollution exposures in patients with mild high BP residing in vulnerable disadvantaged communities across Detroit and 2) explore clinical markers (e.g., age, sex, body mass index) that predict BP-responses to PAC intervention to better target at-risk populations in larger-scale trials and future real-world clinical settings. A randomized, double-blind, sham-controlled parallel limb trial of overnight bedroom PAC use versus sham with 200 Detroit community individuals with mild high BP will be conducted. Continuous bedroom PM2.5 levels and home BP will be measured throughout 28 days. PAC will be used in the bedroom before bedtime on the 7th day continuously for 21 days. The reduction of systolic BP (SBP) will be calculated for both the intervention and control groups and the significance will be compared using mixed-effects modeling with repeated measurements of SBP as the dependent variable and group (active vs sham PAC use) as the independent variable with a fixed-effect. Linear multiple regression modeling with SBP as the dependent variable and participant-level characteristics including body mass index, waist circumference, race, ethnicity, or sex as predictors will be explored. This study is expected to demonstrate a significant sustainable reduction in home SBP for active PAC vs sham use in this population with mildly high BP.