SATURDAY, Dec. 1 (HealthDay News) -- Older women who get steroid injections in the spine to treat lower back pain may be at risk for bone loss in their hips, a small study suggests.

It is well known that the anti-inflammatory steroid medications used to treat diseases such as asthma and rheumatoid arthritis may decrease a person's bone mass over time. But it hasn't been clear whether steroid shots -- one treatment option for lower back pain -- are connected to bone loss.

"It's been thought that [the steroids] might stay in the epidural space of the spine," explained study author Dr. Shlomo Mandel, an orthopedic physician at Henry Ford West Bloomfield Hospital, in Michigan.

Safety questions about steroid injections also have been raised in recent months, as U.S. health officials investigate a deadly outbreak of fungal meningitis linked to steroid shots produced by a Massachusetts compounding pharmacy that has since shut down. More than 510 illnesses and 36 deaths connected to the shots have been reported so far, according to the U.S. Centers for Disease Control and Prevention. (Women in the new study did not receive steroid shots connected to the outbreak.)

To look at the bone-loss question, Mandel's team tracked bone-density changes in 28 women who opted for steroid injections to treat their back pain. They compared the findings with medical records from a "control" group of women who were roughly the same age.

Over six months, women in the steroid group lost six times more bone mass in the hip than the comparison group did, although the absolute decrease was "slight," the researchers reported in the Dec. 1 issue of the journal Spine.

But the extent to which the treatment itself is to blame for bone loss isn't clear.

For one, women with chronic back pain may get little exercise, which can accelerate the bone loss seen with aging, explained Dr. Steven Cohen, a professor at Johns Hopkins School of Medicine in Baltimore who focuses on pain research.

It's also not clear how "clinically significant" the bone loss is, Cohen noted. That is, do steroid injections actually raise an older woman's risk of hip fracture?

Still, Cohen and Mandel both suggested that doctors be cautious about giving the injections to older women who are especially vulnerable to the bone-thinning disease osteoporosis -- including thin women who are white or Asian.

"This is not intended to alarm anyone," Mandel said. "I think that steroid injections have a place in treating low back pain. But we should use them judiciously."

In the real world, though, that may not always happen.

In general, steroid injections are potentially helpful when the back pain involves some sort of nerve-root irritation -- such as when a spinal disc is herniated and compressing a nerve.

But they're not so useful, Cohen noted, for pain from spinal stenosis, a narrowing of the spinal column that often is at the root of back pain in older people.

Doctors may overuse steroid injections -- sometimes because the underlying cause of a patient's back pain is hard to ascertain.

There's also the financial aspect, Mandel pointed out. In the United States, a single steroid spinal injection can cost a few hundred dollars.

"I usually present steroid injections as a 'middle-of-the-road' option," Mandel said. That means giving them a try after conservative treatments, such as physical therapy and non-steroid anti-inflammatory drugs (NSAIDs), fail to help. Surgery is typically the last resort.

If you get no relief after a couple steroid injections, it is probably unwise to keep trying, Cohen said. On the other hand, if you feel better after one, don't get another -- at least not until the pain returns.

"Doctors certainly shouldn't just habitually do a series of injections," Cohen said. "It should be based on a patient's response."

Further, larger studies are still needed to see how significant the bone loss seen in this study might be. Mandel suggested that if you are an older woman who is finding pain relief from steroid injections, it would be wise to talk to your doctor about ways to protect your bone mass -- such as taking calcium and vitamin D.

Cohen also stressed that other back-pain treatments have risks as well. For older adults, he noted, long-term use of NSAIDs may raise the risk of heart problems.

"And the risks from surgery or narcotic painkillers are definitely greater than the risks from epidural steroids," Cohen said. "Unfortunately, there is no risk-free treatment."

Just as unfortunate, Cohen added, there seems to be no cure for low back pain. Even after surgery, the most extensive treatment, symptoms typically return eventually.

More information

Learn more about low back pain from the U.S. National Institute of Neurological Disorders and Stroke.