A new study reports that micro- and nanoplastic particles are detectable in the blood supplying the heart in some people who have had a heart attack, and that smokers show markedly higher levels. Researchers compared levels of micro- and nanoplastics in blood associated with the heart between people who smoke and those who do not. The study finds that smokers are about six times more likely to have detectable micro- and nanoplastics in that blood than non-smokers. The findings suggest that cigarette smoking may increase exposure to these particles, potentially because smoking could facilitate delivery of microplastics into the bloodstream. The study therefore connects smoking status with both the presence and likelihood of detection of micro- and nanoplastics in a group of heart-attack patients. The articles present these results as evidence of an association, not proof that microplastics cause heart attacks. Further research is needed to clarify how particles enter the body and whether they play any role in cardiovascular outcomes.