S-05-4: ENVIRONMENTAL POLLUTANTS AND BLOOD PRESSURE

Abstract

Pollution via air, land and water was estimated to cause over nine million deaths globally in 2019. The vast majority of these deaths and associated economic losses occur in LMICs. It is estimated that almost seven million of these annual deaths are due to air pollution, which is increasing, due to an increase in outdoor sources whilst there has been a global decrease in household air pollution since 2000. Of deaths caused by air pollution, it is estimated that approximately half are caused by cardiovascular disease (CVD) with about one third due to coronary heart disease and one fifth due to stroke. One of the mechanisms whereby air pollution impacts adversely on CVD health is via raised blood pressure (BP). Lead pollution which is thought to cause almost one million deaths per year globally is also linked to increased BP levels and thereby to adverse CV outcomes. This presentation will focus on air pollution and BP, since air pollution from combined indoor and outdoor sources is the major contributor to pollution-induced mortality. Air pollution is cause by a mixture of particles or particulate matter (PM) and gaseous compounds which consist of nitrogen oxides. The PM which consists of solid and liquid particles is classified by its aerodynamic diameter across a wide range and those with a diameter < 2.5pm (PM2.5) are commonly used to evaluate this form of pollution. Short and longer-term exposures to elevated outdoor PM2.5 have been shown to be associated with higher BP and incident and prevalent hypertension. The mechanisms involved are thought to include damage to the vascular endothelium, via inflammatory and pro-oxidative reactions. Few high-quality data linking different parameters of air pollution and effects on BP are available from around the world, particularly those areas worst affected by pollution. Using the May Measurement Month (MMM) database, associations between BP and pollution are under investigation in retrospective and prospective studies. In the retrospective studies data collected on the bespoke MMM app from 29 countries in MMM18 and MMM19 allow linkage between longitudinal and latitudinal coordinates of where BP was screened and PM2.5 pollution, based on data collected from ground monitors, satellite observations, meteorological data and land use. In prospective studies from MMM21 data arising from 12 cities in the Philippines, Vietnam, Thailand and Indonesia, BP results and PM2.5 levels are in progress using linear mixed models to evaluate cross-sectional associations at the individual and screen-site levels.