Living in a U.S. coastal county bordered by ocean waters with very high concentrations of microplastics may increase the risk of heart and metabolic diseases, such as Type 2 diabetes, coronary artery disease, and stroke. This risk was higher compared to residents of coastal counties with low levels of microplastic pollution in nearby waters, according to new research published in the Journal of the American Heart Association.

This study is one of the first large-scale investigations to suggest a potential link between residing near waters heavily polluted with microplastics and the development of chronic health conditions. Plastic pollution, traditionally viewed as an environmental concern, is now being recognized as a public health issue.

Microplastics are minuscule plastic particles less than 5 millimeters in size, originating from the breakdown of larger plastic waste like food packaging, synthetic fabrics, and personal care products. These particles, including even smaller nanoplastics, have been detected in drinking water, seafood, and the air. Coastal areas often experience seawater intrusion, leading to a high concentration of contaminants, including microplastics, in groundwater aquifers.

The research analyzed the association between the concentration of plastic particles in ocean water near coastal communities and the incidence of Type 2 diabetes, coronary artery disease, and stroke among residents. The study divided marine microplastic pollution levels within 200 nautical miles of the counties into four categories based on mean marine microplastic levels:

• Low pollution (0–0.005 pieces/m³)
• Medium pollution (0.005–1 pieces/m³)
• High pollution (1–10 pieces/m³)
• Very high pollution (10+ pieces/m³)

The analysis revealed that residents of U.S. coastal counties with very high levels of microplastic pollution had a higher prevalence of Type 2 diabetes, coronary artery disease, and stroke compared to those in counties with low pollution levels. The study also noted a higher prevalence of these diseases in U.S. counties along the Gulf of Mexico and Atlantic coasts compared to the Pacific coast.

Even after adjusting for various factors like age, gender, socioeconomic status, and environmental considerations, the association between high microplastic pollution levels and cardiometabolic diseases remained consistent. The study highlights the pervasive nature of microplastic pollution, emphasizing that it affects everyone, irrespective of their location.

While the research focused on pollution in ocean water, microplastics are omnipresent, found in drinking water, food, and the air. The full impact of microplastics on health is not yet fully understood, but the study underscores the urgent need for action to address plastic pollution as both an environmental and potential health crisis.

Future research areas identified by the study include understanding how microplastics enter the human body, determining harmful levels of microplastics, identifying where these particles accumulate in the body, and assessing the long-term health effects of microplastic exposure.