New Delhi: A new study published in the European Heart Journal reveals that fat stored within muscles significantly raises the risk of heart disease, including heart attack and heart failure, regardless of a person’s body mass index (BMI). This finding underscores the limitations of traditional measurements like BMI or waist circumference in assessing heart disease risk.
The research showed that individuals with higher levels of intermuscular fat—fat stored within muscle tissue—were more likely to experience coronary microvascular dysfunction (CMD), a condition that damages the tiny blood vessels supplying the heart. These individuals also faced a higher likelihood of hospitalization or death due to heart-related conditions.
Notably, those with both high levels of intermuscular fat and evidence of CMD were at the greatest risk of heart attack, heart failure, and mortality. According to Professor Viviany Taqueti, Director of the Cardiac Stress Laboratory at Brigham and Women’s Hospital in the US, this discovery offers a new way to identify high-risk individuals. “Intermuscular fat raises the risk of heart disease regardless of body mass index,” she said, emphasizing the importance of understanding this risk factor in heart health.
The study analyzed the body composition of 669 participants over a period of approximately six years. Researchers used CT scans to measure the amount and location of fat and muscle in the participants’ torsos, focusing on a metric they termed the “fatty muscle fraction.” This ratio calculated the proportion of intermuscular fat relative to total fat and muscle.
The results showed that for every 1% increase in the fatty muscle fraction, there was a 2% rise in the likelihood of CMD and a 7% increase in the risk of severe heart disease. Importantly, these risks were independent of other known factors, including BMI.
In contrast, individuals with greater amounts of lean muscle exhibited a lower risk of heart disease. Fat stored beneath the skin (subcutaneous fat) was not linked to an increased risk, highlighting the specific dangers of intermuscular fat.
Researchers believe that fat stored in muscles contributes to inflammation and impaired glucose metabolism, which can lead to insulin resistance and metabolic syndrome. These conditions, in turn, may damage blood vessels, including those that supply the heart, as well as the heart muscle itself.
The team is now exploring how these treatments can improve body composition and reduce the risk of metabolic heart disease. Their research highlights the need for a more nuanced approach to heart disease prevention, focusing on intermuscular fat as a critical risk factor.
This study broadens the understanding of how fat stored in different parts of the body affects heart health, offering potential pathways for more targeted interventions to improve cardiovascular outcomes.