Potential Link Between Exposure to Urinary Metals and Heart Failure Risk Among American Indian Adults

Exposure to environmental metals may increase the risk of heart failure among American Indians, who are disproportionately affected by heart disease, according to a study presented at the American Heart Association’s Scientific Sessions 2023 in Philadelphia, Pennsylvania.

Chronic exposure to metal was identified as an individual risk factor for heart disease. However, not enough studies exist to determine the role of metal exposure on health failure and its subtypes. For many indigenous communities in the United States, the burden of cardiovascular disease (CVD) is high, and they have been historically exposed to moderate and high levels of environmental metals.

For this study, Irene Martinez-Morata, MD, MPH, and colleagues evaluated the association between heart failure risk in American Indian adults and urinary metal levels. The analysis is part of the Strong Heart study, the most extensive study on CVD and its risk factors in American Indians.

According to the study authors, abandoned mines in the southwestern United States, where many tribal reservations are located, have left a legacy of environmental contamination, impacting the health of tribal communities.

The study comprised 2,706 patients, majorly female (58%) with a mean age of 56 years, who had urinary metals at the start of the study (1989-1991). Most participants live in Arizona, Oklahoma, North Dakota, and South Dakota.

The study revealed that 444 participants developed heart failure. According to the researchers, the baseline levels of all metals were higher among people who developed heart failure. In addition, the researchers observed that higher levels of urinary cadmium, molybdenum, and zinc were associated with a higher risk for heart failure.

“Essential metals are naturally present in food as these metals have essential bodily functions,” Dr. Martinez-Morata said, however, high levels can be harmful. “Excess exposure to essential metals usually comes from contamination of the air and water due to industrial mining or other activities. Natural foods are mostly not a source of excess exposure.”

The researchers found that the most vital links to heart failure among participants included an ejection fraction–the percentage of blood the heart can pump with each beat–of less than 50% and higher levels of urinary molybdenum or zinc.

“Uncovering the role of metal exposures on the development of heart failure may offer new opportunities for early prevention at the individual and community levels,” Dr. Martinez-Morata concluded.

Sources: AHA