What’s the Difference Between Osteoporosis and Osteoarthritis?

WHAT’S IN A NAME? WELL, if it’s osteoporosis and osteoarthritis, for starters, a shared prefix. “Osteo” means bone, and that matching descriptor also spells confusion for many seniors, who are disproportionately affected by both conditions.

“This kind of confusion is something that we see almost daily,” says Dr. Gianluca Toraldo, an endocrinologist and the director of the Bone Health Clinic at Lahey Hospital & Medical Center in Burlington, Massachusetts. That’s because besides sounding similar, a major shared risk factor for the development of both chronic conditions is aging.

But from symptoms – or a lack thereof – to how each impacts the body and the ways in which they’re managed, the two conditions are totally different.

Osteoporosis refers to “porous bone,” or a thinning of bone, where the quality and density of bone is decreased, so that it becomes weak and brittle. This puts a person is at higher risk for sustaining a fracture. However, there are typically no other noticeable symptoms before a bone break. “So it’s a silent disease until a fracture occurs,” says Dr. Meryl LeBoff, chief of the calcium and bone section and director of the Skeletal Health and Osteoporosis Center and Bone Density Unit at Brigham and Women’s Hospital in Boston. Apart from that, there are generally no outward signs that a person may have osteoporosis, which affects about 10 million in the U.S., predominantly women.

By contrast, osteoarthritis is an inflammatory condition that affects the joints – like the hips, knees, spine and joints in the hands. Unlike with osteoporosis, this most common form of arthritis can cause a range of symptoms. Those include joint stiffness, declining flexibility, bone spurs and, perhaps most noticeably, pain.

Despite these obvious and significant differences, osteoporosis and osteoarthritis mix-ups persist. Many people have only a faint idea that they’re at risk or are just learning about one or both conditions. Toraldo mainly sees patients with osteoporosis, but he says sometimes patients with osteoarthritis symptoms come to him, confusing the two. In fact, sometimes patients come in and say simply, “I’m here because I have ‘osteo,’” he notes. “It doesn’t tell you anything.”

Are the Conditions Linked?

The short answer is not really, experts say.

But some people have both osteoarthritis and osteoporosis. So while they’re not directly associated, they share certain risk factors, such as age and gender. “Both conditions are more common in women than they are in men – although clearly they both can affect men as well,” says Dr. Andrea Singer, chief medical officer at the National Osteoporosis Foundation and director of women’s primary care at MedStar Georgetown University Hospital in Washington.

Genetics may also put a person at higher risk of developing each condition as well. “Both conditions tend to run in families,” Singer points out.

But one condition doesn’t directly cause or raise a person’s risk of developing the other, clinicians say. That said, having one doesn’t protect you against developing the other, either. It was once thought that having OA might protect a person against osteoporosis. In fact, osteoporosis – which is typically diagnosed by scanning bone density – may be obscured by bone growth around joints affected by osteoarthritis. So, osteoporosis can sometimes be obscured during a bone scan test by the presence of OA.

Past research LeBoff was involved in found that 25% of patients studied with advanced osteoarthritis, who came in to Brigham and Women’s Hospital for joint replacement, also had osteoporosis, according to bone density criteria. “So it really changed the concept that the osteoarthritis patients did not get osteoporosis, when in fact a subset of them do get osteoporosis,” LeBoff says. “It’s important to consider that in some patients.”

For those undergoing joint replacement surgery for OA – like knee or hip replacement – having osteoporosis as well can significantly affect how successful the procedure is. Because a replacement joint must be placed in bone, it makes a difference whether that bone is strong or the quality is diminished and the bone mineral density decreased. If you have a bone with osteoporosis, it’s quite possible that the hardware won’t stay in the bone, requiring another operation on the joint. The chance that the replacement doesn’t work properly is very high, Toraldo says. “In my opinion, a person with osteoarthritis must be evaluated for osteoporosis.”

In fact, a study published in The Journal of Arthroplasty last year found that one-quarter (24.5%) of total joint replacement patients meet criteria to receive osteoporosis medications, but only 5% actually receive therapy for the condition before or after surgery. The researchers say a lack of osteoporosis screening and treatment of these patients may contribute to an increased risk of fracture around the joint implants, or what’s called periprosthetic fracture.

Testing for Osteoporosis vs. Osteoarthrtis

With osteoarthritis, early signs like tenderness, swelling and pain in affected joints may be tip-offs that it’s time to see the doctor for a closer evaluation.

Often X-rays are done on the joint or joints affected to check for loss of cartilage – a hallmark of OA – or diminished joint space, which signifies cartilage loss. “Osteoarthritis is inflammation in the joints that is really common as people get older, and there can definitely be some changes seen on X-rays,” says Dr. Lyn Weinberg, division director for geriatrics at Allegheny Health Network, which is based in Pittsburgh. Besides narrowing of joint space, she notes, that can also include fluid buildup in the joint – a sign of inflammation.

With osteoporosis, however, because it’s usually asymptomatic, experts emphasize the importance of screening. That’s necessary to detect it early on, so it can be managed to reduce fracture risk. The bone density test that’s used most frequently to check patients for osteoporosis is called dual-energy X-ray absorptiometry, or DXA or DEXA.

The U.S. Preventive Services Task Force recommends women 65 years and older be screened for osteoporosis to prevent fractures related to the bone disease. Some postmenopausal women under 65 should also be considered for screening based on a clinical assessment of their risk factors, such as having parents who’ve sustained hip fractures, the independent expert panel recommends.

The USPSTF says the current evidence is insufficient to assess the benefits and harms of screening for osteoporosis in men.

But some other guidelines, including from the National Osteoporosis Foundation, do address men. The NOF recommends that men age 70 and older have a bone density test, and the same for women 65 and older. Those with risk factors for osteoporosis are recommended for screening earlier. And the NOF also advises anyone who breaks a bone after age 50 to have a bone density test.

Managing Osteoarthritis and Osteoporosis

Whether you have one condition, the other or both, clinicians say ongoing management is key. That helps to quell symptoms of osteoarthritis and to lower fracture risk with osteoporosis.

Options to relieve symptoms – most notably pain – for osteoarthritis include:

  • Pain relievers like acetaminophen.
  • Nonsteroidal anti-inflammatory drugs like ibuprofen.
  • Steroid injections into the joint.
  • Hyaluronic acid – fluid that’s injected to replace lacking joint lubricant.
  • Physical or occupational therapy.
  • Joint replacement for those with more advanced osteoarthritis, when other therapies aren’t enough to relieve pain or overcome disability or functional issues.

For those who have osteoporosis, treatment – like the condition itself – differs markedly from OA.

That includes making sure, first and foremost, that a person is getting enough calcium and vitamin D through diet and supplementation as needed. For most adults that equates to at least 1,000 milligrams of calcium. Women over 50 should get at least 1,200 mg of calcium per day. While there’s more variation with vitamin D, experts commonly suggest getting at least 800 international units, or IU; and some advocate for much more.

So you’ll want to talk to your doctor about what’s suggested for you.

In addition medications may be recommended that reduce bone loss or help build bone. Often patients are prescribed a medication to decrease bone breakdown and then another to stimulate bone formation. The goal is to reduce fracture risk, which can help keep patients on their feet and healthy for longer.

Similarly, lifestyle – not only diet, but also exercise – putting weight on bones by walking for example, is important to keep them as strong as possible. And you’ll be doing your joints a favor, too.

When it comes to the prevention or management of osteoarthritis, Weinberg says, “the most important thing that I stress to seniors is just staying physically active as much as possible. So walking, swimming, things that are kind of like low pressure on the joints are really great just to keep that muscle strength up around the joints, to keep the joints stable.”

Written by:  Michael O. Schroeder, Staff Writer, U.S. News