Humans with relatively more fat hidden in and around their muscles are faced with a higher risk of death or hospitalization of heart disease, according to new research – an association that persists regardless of the body mass index ( BMI).
The results highlight tIt insufficient BMI as a marker of heart health and indicates A potential risk factor in cardiovascular disease that justifies a more in -depth study.
“Knowing that intermuscle fats increase the risk of heart disease gives us another way to identify people at high risk, regardless of their body mass index,” said co-author Viviany Taqueti, director of the laboratory Heart stress at Brigham and Women’s Hospital.
The effects on the health of the fatty muscles remain misunderstood, note the authors, but it has been associated with resistance to insulin and type 2 diabetes, among other diseases. This is the most exhaustive study to date in the influence of fatty muscle on heart disease, they say.
Beyond the illumination of this link, the study highlights the limits of measures such as BMI in the universally risk assessment of heart disease.
“Obesity is now one of the largest world threats to cardiovascular health, but the body mass index – our main metric to define obesity and intervention thresholds – remains a controversial and defective marker of the prognosis cardiovascular, “said Taqueti
“This is particularly true in women, where the high body mass index can reflect more” mild “fat types.”
Everyone needs body fat, of course, including small deposits anchored among our skeletal muscle fibers called intermuscular adipose tissue (IMAT).
Intermuscular fat is present in most muscles, but the quantity varies between individuals and tends to increase with age. Sometimes too much intermuscle fat accumulates in the middle of the skeletal muscles, a condition known as fat infiltration or myostosis.
In previous research, high levels of IMAT has been associated with resistance to insulin and metabolic syndrome, as well as loss of strength and mobility problems. However, many things remain unknown on the IMAT, including the way it affects cardiovascular health.
Taqueti and his colleagues have sought a link between muscle quality and coronary microvascular dysfunction (CMD) – a condition in which small blood vessels serving the heart are damaged – more other cardiovascular diseases.
“In our research, we analyze muscles and different types of fat to understand how body composition can influence small blood vessels or” microcirculation “of the heart, as well as the future risk of heart failure, heart attack and death “Said Taqueti.
The study involved 669 subjects, all the patients of Brigham and Women’s Hospital with chest pain or shortness of breath but no sign of obstructive coronary disease. About 70% were women and 46% were non -white, with an average age of 63, report the authors.
The researchers examined the heart of each patient with a cardiac comput / CT). They also used computed tomography to reveal the body composition, measure the quantities and the locations of fat and muscle.
Their analysis involved a measure called fatty muscle fraction – the ratio of intermuscular fat / skeletal muscle more of intermuscular fat.
Researchers followed subjects for about six years, recording deaths or hospitalizations due to a heart attack or heart failure.
Patients with high IMAT levels were more likely to have a CMD, revealed the study, and faced a higher risk of death or hospitalization by heart disease.
Each 1% increase in the fraction of fatty muscles has given a higher risk of CMD 2%, according to researchers, and a 7% higher risk of a major unwanted cardiovascular event – regardless of BMI and other known risk factors.
Patients with excess imat plus CMD evidence are in particular danger, suggests the study, with an even higher risk of death, heart attack and heart failure.
Those who have more lean muscle had a lower risk, report the researchers. The storage of fat elsewhere in the body, as under the skin, has not increased the risk.
“Compared to subcutaneous fat, fat stored in muscles can contribute to inflammation and alteration of glucose metabolism leading to resistance to insulin and metabolic syndrome”, explains Taqueti. “In turn, these chronic insults can damage blood vessels, including those that provide heart and heart muscle itself.”
The study has notable limits, as the authors recognize – and as two other researchers describe it in an editorial that accompanies it.
Future research should deepen the link between fatty muscles and heart disease, she says, and study how we can use this information to save lives.
The study was published in the European Heart Journal.
