Although BMI is a common reference, it does not reflect individual CVD risk, so other tools, such as computed tomography ( CT), are needed to assess body composition and differentiate between fat and muscle. This is according to an article in the European Heart Journal, dated January 20, 2025.

Intermuscular fat is a type of body fat found between muscle fibers. Fat infiltration of skeletal muscle ( SM), or intermuscular adipose tissue ( IMAT), reflects muscle quality and is associated with inflammation, a key determinant in cardiometabolic disease.

Intermuscular fat (IMAT), which is a type of fat within skeletal muscle that varies between individuals and is associated with insulin resistance and type 2 diabetes. Unlike the fat in meat for consumption, IMAT in humans has inflammatory properties that may affect metabolic function and muscle health. Although its relationship to CVD is not fully understood, it has been identified as a possible risk factor.

Coronary microvascular dysfunction (CMD) is a condition in which blood flow to the heart is reduced, even though the major arteries appear normal. It can be measured with positron emission tomography (PET) and has been linked to obesity, heart failure, stroke, and mortality. In addition, CMD is associated with inflammation and stiffness in the heart, even in people without conventional risk factors.

CMD has been shown to be common in people with obesity and its severity increases with BMI, making it a better indicator of CVD risk than BMI alone. However, the quantity and quality of skeletal muscle may also influence this risk, suggesting that more factors than just body weight need to be assessed.

Because BMI has limitations in predicting CVD, the researchers posit that IMAT and skeletal muscle quantity may affect CMD and cardiovascular risk independently of obesity. Assessing these factors could improve risk detection and guide better prevention and treatment strategies.