Coastal counties with very high marine microplastic levels had higher rates of diabetes, heart disease, and stroke compared to coastal counties with lower marine microplastic levels, according to a new study published Wednesday in the Journal of the American Heart Association.
Microplastics are tiny plastic pieces measuring less than 5 millimeters in length -- approximately the size of a pencil eraser -- that result from the breakdown of larger plastic debris such as plastic bags, bottles, personal care products and synthetic microfibers, according to the National Oceanic and Atmospheric Administration. Microplastics accumulate in the ocean and are ingested by fish and other marine organisms, potentially exposing them -- and consequently humans -- to toxic chemicals.
"Pathways such as contaminated seafood, drinking water, and even air inhalation could allow marine microplastics to enter the human body, making this a population-wide exposure risk with measurable health consequences," Dr. Sarju Ganatra, senior author on the study and medical director of sustainability and vice chair of research in the Department of Medicine at Lahey Hospital & Medical Center, told ABC News.
The study was conducted using the National Centers for Environmental Information's geodatabase with marine microplastic levels recorded from 2015 to 2020 for counties within 200 nautical miles of the U.S. coastal margin.
Counties were then grouped into those with low (0-0.005 pieces/m3), medium (0.005-1pieces/m3), high (1-10 pieces/ m3), and very high (>10 pieces/ m3) marine microplastic levels. The rates of diabetes, heart disease, and stroke in these counties were then obtained using the 2022 CDC Population-Level Analysis and Community Estimates dataset and the 2015-2019 American Community Survey.
Teen raises awareness about microplastics in oceansAmong 152 coastal counties studied, those with very high levels of marine microplastics showed higher rates of diabetes, heart disease and stroke -- at 18%, 7% and 9%, respectively -- among adults with an average age of 43 years. This was true even after adjusting for race, access to doctors, socioeconomic status and environmental factors.
Studies examining potential links between microplastics and cardiometabolic diseases are relatively new, and this study suggests that on a population-based level, there may be an association between microplastic exposure and chronic health conditions.
Microplastics may trigger inflammation, oxidative stress, and blood vessel damage, which can increase the risk for diabetes, heart disease and stroke, according to emerging research.
"One study found individuals with microplastics in carotid plaques had a higher risk of myocardial infarction and stroke … [and] animal models demonstrate that microplastics induce insulin resistance, vascular inflammation, oxidative stress, myocardial injury … all of which are implicated in cardiometabolic diseases," Ganatra wrote.
Hidden dangers on Easter Island: The hunt for microplasticsThis latest study only examined marine microplastic levels and did not include groundwater or other potential sources. Additionally, researchers will need to conduct additional studies to allow for comparisons between rates of cardiometabolic diseases in coastal versus noncoastal counties with varying levels of marine microplastics.
"The findings should ring alarm bells for all regions, given the pervasive presence of microplastics in our water, food, air, and packaging materials … These findings support a unified public health and environmental response -- integrating climate action, pollution mitigation, and chronic disease prevention under a 'One Health' framework," Ganatra added.
Dr. Jennifer Miao is a board-certified cardiologist, critical care and interventional cardiology fellow at Yale School of Medicine/YNHH, and a fellow with the ABC News Medical Unit.
