Living Near Microplastic-Polluted Oceans Linked to Higher Risk of Cardiometabolic Diseases

Results of a study published in the Journal of the American Heart Association on June 18, 2025, suggest that living near ocean waters heavily polluted with microplastics may be associated with a significantly increased risk for cardiometabolic diseases, including type 2 diabetes, coronary artery disease, and stroke. The researchers analyzed health data from 152 coastal US counties situated within 200 nautical miles of ocean waters, categorizing those waters by levels of microplastic pollution. Counties exposed to “very high” levels of microplastics in adjacent waters had notably higher rates of these chronic diseases compared with counties with low levels of pollution. Specifically, the study found an 18% higher prevalence of type 2 diabetes, a 7% increase in coronary artery disease, and a 9% increase in strokes in the most polluted areas. These differences remained significant even after adjusting for demographic, socioeconomic, environmental, and healthcare access variables.

Microplastics, defined as plastic particles smaller than 5 mm in diameter, typically originate from the breakdown of larger plastic items such as packaging, synthetic clothing, and personal care products. These particles, along with even smaller nanoplastics, are increasingly found in air, drinking water, seafood, and groundwater due to seawater intrusion—particularly in coastal regions. Although the study focused on ocean water pollution, the authors emphasize that microplastics affect people regardless of their proximity to the sea due to their widespread presence in the environment. The pollution categories used in the study ranged from low (0-0.005 plastic pieces per cubic meter of water) to very high (≥10 pieces per cubic meter). These levels were used to correlate disease prevalence at the county level using data from the CDC and US Census Bureau from 2015 to 2020.

The researchers note that although the study identifies strong associations, it cannot establish a direct cause-and-effect relationship due to its ecological design. In addition, individual exposure to microplastics was not measured, and the biological mechanisms by which microplastics may affect health remain unclear. However, experts believe the particles could trigger inflammatory or oxidative stress pathways that contribute to chronic illness. The geographic breakdown of the data also revealed that coastal counties along the Gulf of Mexico had higher disease rates than those along the Atlantic and Pacific coasts, suggesting regional differences in pollution levels or exposure pathways.

The study’s senior author, Dr. Sarju Ganatra, emphasized that the findings highlight a potentially serious public health concern, urging policymakers to treat plastic pollution as both an environmental and health crisis. The research also draws attention to the healthcare industry’s reliance on single-use plastics, which contributes significantly to environmental plastic waste. In a news release from the American Heart Association, experts not involved in the study, including Dr. Justin Zachariah of Baylor College of Medicine, echoed the call for further individual-level research and public transparency on plastic content in consumer products. The research team is already planning follow-up studies to directly measure human exposure to microplastics and assess their impact on biological markers of cardiovascular stress and inflammation. Overall, the study marks an important step in understanding how environmental pollution, particularly from plastics, could be influencing chronic disease patterns in vulnerable populations.