The Link Between RA and Bone Loss
Find out what you can do to keep your bones strong.
At the onset of rheumatoid arthritis (RA), a rheumatologist takes immediate steps to control the inflammation that causes severe pain, swelling and destruction of cartilage. Cartilage is not the only tissue at risk, however. The effects of inflammation and the drugs used to control inflammation can also destroy bones, leading to osteoporosis.
Seoyoung C. Kim, MD, a rheumatologist and researcher at Brigham and Women’s Hospital in Boston, has studied the connection among RA, common RA drugs to fight inflammation and the loss of bone mineral density that can increase the risk of fracture.
“The bottom line is that people with RA have a high risk of osteoporotic fracture at the typical sites: the hip, forearm, pelvis,” she says. Dr. Kim estimates that if you have RA, your risk of these fractures is 25 to 30 percent higher than among the average population.
“We are all losing bone mass, but some things, like RA, speed up that process,” explains Michael DiMuzio, PhD, executive director of the North Shore Osteoporosis Center in Highland Park, Ill.
RA’s inflammation contributes to bone damage, possibly by stimulating osteoclasts -- bone cells that deplete bone minerals. Prednisone, a corticosteroid drug used for decades to control inflammation, is one of the notorious culprits in bone mineral density loss.
“Prednisone stops the function of bone-forming cells. When that happens, the body still needs calcium, so it takes it out of the bone, but it’s not allowing the bone-forming cells to put it back,” he says.
The result: Weakened bones that increase a person’s risk for painful fractures if they fall.
Do Biologics Boost Bone?
Disease-modifying antirheumatic drugs (DMARDs) like methotrexate can interfere with the body’s natural process of bone remodeling – the body’s way of breaking down and rebuilding bone. Newer inflammation-fighting drugs, like the biologic class of drugs that include the TNF inhibitors etanercept and adalimumab, can control inflammation without interfering with bone remodeling.
Some studies suggest they may help reduce bone loss or boost bone regrowth for RA patients. But experts are divided on whether the bone mineral density benefit of using these powerful drugs is that they aggressively control inflammation and, therefore, prevent bone loss, or whether the drugs themselves protect the bones apart from their inflammation-fighting power.
Studies on the positive effects of biologic drugs on bone mineral density are early, small and somewhat mixed. Dr. Kim led a study using data for the years 1996–2008, the prime years when biologic drugs were coming onto the market. She and her colleagues looked at hospitalizations for fractures of the hip, wrist, forearm or pelvis and found only a slightly better outcome for RA patients using TNF inhibitors.
According to an article published in 2013 in Osteoporosis International, small studies have suggested biologic DMARDs preserve bone mineral density and have a positive impact on bone remodeling. However, the authors say they were unable to demonstrate a reduced fracture risk in older adults with RA.
“Whether TNF inhibitors can improve the risk of fracture is still up in the air,” Dr. Kim says.
Your Bones Are Constantly Changing
Bones are active organs that change every day throughout our lives, says DiMuzio. Because our bodies stop actively building bone mass at about age 30, we are at increased risk of developing osteoporosis as we age.
Bone mineral density loss can occur over time due to various factors: chronic inflammation, long-term use of corticosteroid drugs, inadequate dietary intake of calcium, or lack of weight-bearing exercise that strengthens bones, DiMuzio explains.
In addition to the bone-leaching potential of corticosteroids or even methotrexate – which was used at higher, more toxic doses in the past to treat RA – other factors common in people with RA can contribute to bone loss. Pain, swelling or fatigue may keep you from daily weight-bearing activities that can help strengthen bone.
Building a Bone-Healthy Lifestyle
To prevent bone mineral density loss and increased fracture risk, people with RA should “modify any risk factors you can, because prevention is key. If you have RA, you could also start preventive measures at a younger age,” suggests Carolyn Felton, MD, a rheumatologist at Piedmont Arthritis and Rheumatology in Atlanta.
Consumption of calcium in food or supplements can help replenish this lost mineral that is a building block of healthy bone. Yet drugs like proton pump inhibitors (PPI), used by some people with RA to protect the stomach from the effects of nonsteroidal anti-inflammatory drugs (NSAIDs), can interfere with calcium absorption.
Dr. Kim says the best solution for that is to take your PPI on an empty stomach before breakfast and then take a calcium supplement with food, because that promotes better absorption.
Aggressively treating inflammation early may prevent damage to bones, cartilage and other tissue, Dr. Felton says. Medications effective at treating the underlying inflammation help prevent bone loss and loss of function.
In time research will more definitively show whether there is evidence of bone-building benefits of TNF inhibitors. But doctors do agree the use of drugs to control inflammation is a good way to protect bones and other tissue. In addition to taking their medications, RA patients can protect their bones by
- Eating a healthy diet rich in calcium
- Getting adequate sun exposure for vitamin D synthesis
- Taking calcium and vitamin D supplements
- Doing regular weight-bearing exercise
American College of Rheumatology guidelines also recommend avoiding smoking and limiting alcohol intake to keep bones strong.