Scientists from the United States of America have discovered that hidden fat in muscles can lead to a higher risk of dying from heart attacks or heart failure regardless of body weight.
They found that it could be linked to inflammation and insulin resistance which can cause harm to blood vessels around the heart.
The researchers revealed their findings in a study, published on Wiley Online Library, added that simply measuring BMI or waist circumference are not enough to assess the risk of heart health issues.
Conducted from Brigham and Woman’s Hospital in Boston, United States, the researchers analysed data on 669 people being evaluated for chest pain or shortness of breath.
CT scans were carried out on the participants to analyse body composition, measuring the amounts and location of fat and muscle in sections of their torso. This was to determine the amount of fat in the muscles.
The team calculated the ratio of intermuscular fat to total muscle plus fat using a measurement they called the fatty muscle fraction.
Patients were followed up for around six years and the scientists recorded whether any died or were hospitalised for a heart attack or heart failure.
Their findings revealed that people with higher amounts of fat stored in their muscles were more likely to have damage to the tiny blood vessels that serve the heart, and they were more likely to go on to die or be hospitalised for heart disease.
According to the study, for every 1 per cent increase in the ratio of fatty muscle fraction, there was a 2 per cent increase in the risk of damage to the heart’s small blood vessels, regardless of the BMI, and a 7 per cent increased risk of developing serious heart disease.
Lead author of the study, Professor Vivianay Taqueti, said fat stored in the muscles may be contributing to inflammation of blood vessels and insulin resistance.
She explained stating, “In turn, this chronic insulin resistance can cause damage to blood vessels, including those that supply the heart, and the heart muscle itself.
“Knowing that intermuscular fat raises the risk of heart disease gives us another way to identify people who are at high risk, regardless of their body mass index.’
According to her, the means to lowering the risk for people with fatty muscles is not known.
“For example, we don’t know how treatments such as new weight-loss therapies affect fat in the muscles relative to fat elsewhere in the body, lean tissue, and ultimately the heart,’ she continued.
“Obesity is now one of the biggest global threats to cardiovascular health, yet body mass index – our main metric for defining obesity and thresholds for intervention remains a controversial and flawed marker of cardiovascular prognosis.”