Older studies have found that fine particulate matter in the air increases the risk of fatal heart attacks. But there was limited evidence about whether taking statins made a difference. We wanted to find out if the risk was different for people taking statins. We also wanted to dive into the adherence question, because we know how patients can get a prescription but not always take it.

Statins change how air pollution impacts cardiovascular health. After following 1.2 million adults in Ontario, Canada for 19 years, we’ve learned that exposure to particulate matter significantly increases cardiovascular mortality. Chronic exposure had more harmful effects among adults who were not using statins. And even among those who were on statins, we found the risk was higher among those who took them inconsistently. This means that if you don’t take your medication as prescribed, you’re more vulnerable.

Our findings underscore the importance of understanding effects across different groups of people. This may motivate the discovery and implementation of more specific strategies to protect people at higher risk—for example, public health campaigns aimed at educating and protecting vulnerable populations or enhancing air-quality monitoring in high-risk areas. And we would like future research looking at how medication and air pollution mitigation may work together to reduce the risk.