Microplastics and their even tinier cousins, nanoplastics, are probably flowing through your blood and building up in your organs like the lungs and liver.

Now, a new study is connecting the dots on microplastics' mysterious correlation with heart attack and stroke risk.

"There are some microplastics in normal, healthy arteries," Dr. Ross Clark, a University of New Mexico medical researcher who led the study, told Business Insider before he presented his findings at the meeting of the American Heart Association in Baltimore on Tuesday.

"But the amount that's there when they become diseased – and become diseased with symptoms – is really, really different," Clark said.