Sleep Affects Bone Health
New research suggests that people who suffer from obstructive sleep apnea (OSA) may be more prone to osteoporosis. This previously unrecognized link between the two diseases is related to the importance of good-quality, uninterrupted sleep for the maintenance of strong bones. Investigators believe that bone remodeling—a process whereby old, stressed bone is carefully disassembled, and new bone takes its place—needs to happen every night while we sleep.
Among adults, about 10% of the skeleton is broken down, recycled, and promptly replaced, every year. In newborns, this remodeling process can result in 100% of the skeleton being completely replaced within the first year of life. Clearly, bone resorption and ossification (new bone formation) are important processes that ensure the ongoing health of our bones.
Sleep apnea is a condition that common among overweight and obese people. Normal sleep is continually interrupted as the airway becomes impeded, forcing the individual to rouse temporarily. Sleep apnea sufferers tend to have poor blood oxygenation, and higher levels of inflammation in the body. Previous research has noted an association between OSA and poorer metabolic and cardiovascular health. OSA also appears to disturb hormone levels.
Investigators are still exploring the various ways that obstructive sleep apnea may interfere with normal bone health and maintenance, but they suspect that poor blood oxygenation during sleep, combined with frequent waking, and disturbances in the production of the sleep-inducing hormone, melatonin, may all play a role in the negative consequences of OSA.
"There are strong indications that daily rhythms are an intrinsic and important element of bone biology," said senior author Dr. Eric Orwoll. "If sleep disorders like obstructive sleep apnea affect bone metabolism, they may have diagnostic and therapeutic implications for many patients, including those affected by sleep apnea in their early, bone modeling years," added lead author Dr. Christine Swanson.
Christine M Swanson, Steven A Shea, Katie L Stone, Jane A Cauley, Clifford J Rosen, Susan Redline, Gerard Karsenty, Eric S Orwoll. Obstructive Sleep Apnea and Metabolic Bone Disease: Insights Into the Relationship Between Bone and Sleep. Journal of Bone and Mineral Research, 2015; 30 (2): 199 DOI: 10.1002/jbmr.2446