Muscle as a predictor of heart health

Body composition (often expressed as the amount of fat relative to muscle) is one of the standard predictors of heart health. Now, new research from the University of California, San Diego shows that gaining muscle doesn’t automatically lower your risk of heart disease.

This research American Heart Association Journal, it turns out that not all muscles are the same. Dr. Britta Larsen says men with large abdominal muscles are at higher risk for heart disease. For men with high muscle density, it’s a completely different story. The denser the muscle, the better. Men with the highest intra-abdominal muscle density had about a quarter of the risk of developing coronary heart disease later in life.

“And the other important thing to note is that we didn’t find this in women. It was just in men,” said lead author and University of California San Diego Herbert Wertheim School of Public Health and Human Geriatric Sciences. Associate Professor Larsen said.

Data were obtained from computed tomography of subjects from the National Institutes of Health’s Multi-Ethnic Study of Atherosclerosis (MESA). Larsen explained that when the study aimed at understanding artery thickening began in 2000, the subjects were in their mid-60s. Participants were recruited from across the United States and followed for 20 years. . Larsen noted that her group tracked the subjects’ medical records for 12 years.

Researchers found that the risk of heart disease in the group with the largest muscles was six times higher than in the group of men with the smallest abdominal muscle area. Larsen said the research team was surprised by the correlation between increased muscle area and increased coronary heart disease.

“Muscle has long been neglected in health,” says Larsen. “Researchers have focused solely on fat. But muscle is a large, active metabolic tissue that is finally starting to get some attention.”

Larsen explains that the difference between muscle area and muscle density boils down to quantity and quality. A computed tomography scan renders a two-dimensional image of him. She says the area of ​​a muscle is determined simply by the number of pixels in the image.

“Density is a little tricky. It’s kind of a surrogate measure of muscle quality,” Larsen said. “This is actually a measure of how much fat has infiltrated into the muscle cavity. Within the muscle itself, how much is pure muscle? What is the fat content?”

The study also found no correlation between muscle and stroke in women as well as men. Researchers distinguished between coronary heart disease and cardiovascular disease, which includes stroke, which is a blockage in the arteries outside the heart.

“This shows that muscle density is not just a surrogate measure of overall health, frailty, and aging,” she says. “Otherwise, strokes and other consequences will also occur.”

Larsen said the study raises many more questions and possibilities for future research. For example, why do women seem to be exempt from muscle-coronary connections?

Larsen said the larger question concerns the biological mechanisms that facilitate connections between men’s muscles and coronary arteries. She said genetics may be involved, but suspicions lie in diet and physical activity.

Co-authors of the paper from the Herbert Wertheim School of Public Health and Human Longevity Sciences at the University of California, San Diego include John Bellettiere, Rowena M. Tam, and Rita Liu. Other UC San Diego co-authors include Matthew Allison, Michael Chriqui, and Jonathan Ankart of the UC San Diego Department of Family Medicine and Public Health. Robin L. McClelland, Department of Biostatistics, University of Washington. Iva Miljkovic, Department of Epidemiology, University of Pittsburgh; Chantal Vella, University of Idaho, Department of Exercise Science, and Pamela Ouyang, Johns Hopkins University School of Medicine.

The MESA study was funded in part by the National Institutes of Health (contracts N01-HC-95159, N01-HC-95160, N01-HC-95161, N01-HC-95162, N01-HC-95163, N01 -HC- 95164, N01-HC-95165, N01-HC-95166, N01-HC-95167, N01-HC-95168, and N01-HC-95169, UL1-TR-000040 and UL1-TR-001079) . The MESA Body Composition, Inflammation, and Cardiovascular Disease auxiliary study was funded by the National Institutes of Health (grant R01-HL-088451).

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