It is common knowledge that as we age we lose a percentage of muscle mass with every decade and our bones also become less dense if we do not take proper care through diet and exercise. However, little attention has been paid so far on how muscle mass affects the complexion of our skeletal system both in terms of internal and external microstructure. A recent study conducted by Mayo Clinic has looked at this very aspect and put forth some very interesting findings that were published in the medical periodical titled, Journal of Bone and Mineral Research (JBMR). (1)
According to lead researcher, Nathan LeBrasseur, Ph.D from the Department of Physical Medicine and Rehabilitation and the Robert and Arlene Kogod Center on Aging at Mayo Clinic, “Our study adds to the growing body of evidence supporting the highly integrated nature of skeletal muscle and bone, and it also provides new insights into potential biomarkers that reflect the health of the musculoskeletal system.” (2)
The study conducted by Mayo Clinic looked at how muscle mass affected two aspects of the skeleton, namely, bone architecture and bone strength. The study examined a total of 589 people out of which, 272 were women. The age of the population under study ranged from 20 to 97 years of age. Bone strength as well as architecture was assessed using high-resolution imaging technologies that were sharp at distinguishing the cortical layer of the bone network from the trabecular layer.
The cortical layer of the bone is a superficial and external layer of the bone that surrounds the marrow cavity and is compact in nature. It’s main function is to support the body, protect organs, help in movement and store and release chemicals including calcium. (3) The trabecular layer is internal layer of softer bone mainly comprising of spongy tissue at the core of vertebral bones in the spine and at the end of long bones inn mature adults. The main function of this layer is to cancellous bone tissue is to supply osteoprogenitor cells that help in the formation and growth of new bone. (4)
The Mayo study found that muscle mass is indeed associated with bone strength but at different places of the anatomy for women and men.
In women, muscle mass was strongly connected to cortical (outer bone strength) at load-bearing location such as:
- Lumbar spine
- Tibia (shin)
Again, for women muscle mass was strongly connected to the micro-architecture of the tribecular bone (internal spongy bone tissue) at the forearms which are a non load-bearing site. This increases chances of fracture especially after menopause at this site unless good muscle mass is maintained.
As per Dr. LeBrasseur, “We found IGFBP-2, which has already been linked to osteoporotic fractures in men, is a negative biomarker of muscle mass in both sexes. This finding could potentially be used to determine people who are at a particular risk for falls and associated fractures. As we develop a better understanding of the complex relationship between muscle and bone, we may find new strategies for early identification and treatment of muscle loss, bone density loss and treatment for osteoporosis.” (5)
- Healthy Muscle Mass Linked to Healthy Bones, but There Are Gender Differences; Science Daily News; Web July 2012; http://www.sciencedaily.com/releases/2012/06/120620133349.htm
- Study links healthy muscle mass to healthy bones; Arthritis Research U.K; Web July 2012; http://www.arthritisresearchuk.org/news/general-news/2012/june/study-links-healthy-muscle-mass-to-healthy-bones.aspx
- Cortical Bone; Wikipedia; Web July 2012; http://en.wikipedia.org/wiki/Cortical_bone
- Cancellous Bone Definition; Spine-Health; Web July 2012; http://www.spine-health.com/glossary/c/cancellous-bone
- Study Finds Gender Differences in Health Muscles, Bones; Mayo Clinic; Web July 2012; http://www.mayoclinic.org/news2012-rst/6954.html
Abstract of the technical report may be accessed at:
- Skeletal muscle mass is associated with bone geometry and microstructure and serum IGFBP-2 levels in adult women and men; JBMR – Via Wiley Online Library; Web July 2012; http://onlinelibrary.wiley.com/doi/10.1002/jbmr.1666/abstract;jsessionid= FF3437BA7FB5CF23EA85680A801C43C8.d02t01