Effect of short-term exposure to particulate matter on mortality rate by cardiovascular disease in Colombia: An observational ecological study with causal machine learning.

Cardiovascular disease (CVD) is an important cause of death in older adults with pre-existing CVD. This study aimed to estimate the causal effect of short-term particulate matter exposure on excess CVD mortality among individuals aged 60 and older in the 10 most populated cities of Colombia. The study utilized publicly available data from 2015 to 2022 on daily CVD, aerosols concentration, and temperature. We estimated the excess deaths by cardiovascular disease based on the daily standardized mortality ratio for each municipality and applied a double machine learning algorithm to estimate the effect of high PM2.5 levels on excess CVD deaths. The results revealed a positive association between short-term PM2.5 exposure and excess CVD deaths. The strongest effect was observed for PM2.5 exposure during the five previous days, with high levels of PM2.5 increasing excess deaths by an average of 27.5% compared to low levels. Additionally, the study found a trend of increasing excess deaths associated with high PM2.5 levels in conjunction with high temperatures. This study provides evidence for a causal link between short-term exposure to elevated PM2.5 levels and increased CVD mortality in older adults residing in major Colombian cities. The findings underscore the importance of implementing air quality improvement measures to mitigate the adverse health impacts of PM2.5 pollution, especially for vulnerable populations.