Joshua Baker, MD, on Intramuscular Fat Accumulation in Rheumatoid Arthritis

Dr Baker discusses his research into the accumulation of intramuscular fat in patients with rheumatoid arthritis, and how exercise can help patients reduce this fat and maintain better muscle strength and density.

Additional Resource:

  • Baker JF, Mostoufi-Moab S, Long J, Taratuta E, Leonard MB, Zemel B. Association of low muscle density with deteriorations in muscle strength and physical functioning in rheumatoid arthritis. Arthritis Care Res. 2021;73(3): 355-363.


Joshua Baker, MD, is an assistant professor of rheumatology and epidemiology at the University of Pennsylvania.


Hi, everyone. My name is Josh Baker. I am an assistant professor of rheumatology and epidemiology at the University of Pennsylvania. I'm here to talk to you a little bit about our study published recently in Arthritis Care and Research, discussing intramuscular fat accumulation in patients with rheumatoid arthritis.

I was interested in this question because we don't think about how arthritis affects skeletal muscle very frequently. We know that inflammation from inflammatory diseases, and in particular rheumatoid arthritis, can affect muscles and weaken muscles. This can be an important contributor to how people feel and how people experience their disease.

We were interested in looking at not just how big people's muscles are and how strong they are, but also how much fat accumulates within them. We looked at patients with RA and looked at them over time, over several years of follow‑up. We looked at what things were predicted, how the fat in their muscles changed over time.

What we found is that people with RA tended to have more accumulation of fat in their muscles if they had higher disease activity, if the arthritis was less well‑controlled, and if they had lower levels of a hormone called insulin‑like growth factor.

Over time, people that had low density to their muscles, suggesting more fat, had worsening of function. They had greater disability over time, lost their ability to do certain tasks, and had worsening of their physical functioning, suggesting that both the disease can contribute to worsening of the fat in their muscles, but also that fat in the muscles can contribute to worsening in function and how people feel.

We're interested in identifying problems with muscles that we can do something about. Right now, there are not a lot of interventions to try and help prevent muscle damage and muscle loss from arthritis and try and promote muscle health.

The main thing that you can do to help your patients is to make sure that they're exercising. Strength training and exercise programs can prevent muscle loss and have shown value, even in patients with arthritis.

The other thing that you can make sure to do is to try and get their disease under really good control. It appears that the inflammatory aspect of the disease contributes to muscle loss. If you have more inflammation, your muscles are less able to grow and respond to exercise. Keeping the disease well‑controlled and getting people more exercise are two really important steps to protecting muscle health over time.

Thanks for listening to me talk about our research. We'll be sure to keep you updated with any additional advances in this area. Keep your patients moving and protect those muscles. Thanks a lot.

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