Preventing Steroid-Induced Osteoporosis: Calcium, Vitamin D, and Bisphosphonates

Why Steroids Attack Your Bones

When you take steroids like prednisone for conditions like asthma, rheumatoid arthritis, or lupus, you’re not just calming inflammation-you’re also quietly weakening your bones. Within just three to six months of starting daily doses of 2.5 mg or more of prednisone, your risk of breaking a bone starts climbing. For some, it jumps five to seventeen times higher than normal. This isn’t a myth or a rare side effect-it’s called glucocorticoid-induced osteoporosis (GIOP), and it’s the most common form of secondary osteoporosis in adults.

Here’s how it works: steroids don’t just reduce swelling. They shut down the cells that build bone (osteoblasts) and wake up the ones that break it down (osteoclasts). About 70% of the bone loss comes from reduced bone formation, and 30% from increased resorption. That means your skeleton isn’t just losing density-it’s losing its ability to repair itself. By the end of the first year on steroids, 12% of patients on 7.5 mg or more will already have suffered a vertebral fracture. Many don’t even feel it until they bend over and hear a pop.

Calcium and Vitamin D: The Non-Negotiable Base

If you’re on long-term steroids, skipping calcium and vitamin D is like trying to build a house without bricks. No matter what else you do, this pair is the foundation. The American College of Rheumatology (ACR) recommends at least 1,000 to 1,200 mg of calcium daily and 600 to 800 IU of vitamin D. If your blood level of vitamin D is below 30 ng/mL-which is common-you’ll need 800 to 1,000 IU daily.

Most people get some calcium from food, but it’s rarely enough when steroids are in the picture. A cup of milk has about 300 mg. A serving of yogurt? Maybe 250 mg. You’d need to eat three to four servings of dairy daily, plus leafy greens and fortified foods, just to hit the minimum. Many patients rely on supplements to fill the gap. Vitamin D is even trickier. Sunlight helps, but in places like Bristol, where winter days are short and cloudy, your skin can’t make enough. Blood tests are the only way to know if you’re deficient.

Without enough calcium and vitamin D, even the strongest drugs won’t work well. Studies show that patients who take these supplements along with bisphosphonates have better bone density outcomes than those who skip them. It’s not optional. It’s the first step-every single time.

Bisphosphonates: The First-Line Shield

Once you’ve got your calcium and vitamin D in place, the next move is usually a bisphosphonate. These are the most studied, most prescribed, and most cost-effective drugs for preventing steroid-induced bone loss. Alendronate (Fosamax) and risedronate (Actonel) are the two most common oral options. Both are taken once a week, and both have been shown in large trials to increase spine bone density by 3% to 4% in the first year-while patients on placebo lose bone.

They cut the risk of spinal fractures by about half. That’s not a small win. In one major trial, patients taking alendronate had a 43% lower chance of vertebral fractures compared to those on placebo. The effect is strongest in the spine, where most steroid-related fractures happen. These drugs work by slowing down the bone-eating cells, giving your body time to rebuild.

But they’re not perfect. Taking them correctly matters. You have to sit upright for at least 30 minutes after swallowing the pill. No lying down. No eating or drinking anything but water. Skip these rules, and you risk serious irritation in your esophagus-something that happens in up to 25% of people who don’t follow instructions. Also, if your kidneys aren’t working well (eGFR below 30), oral bisphosphonates aren’t safe. In that case, your doctor will switch you to something else.

When Oral Bisphosphonates Aren’t Enough

Many patients stop taking their weekly pills. Why? Side effects, forgetfulness, or just the hassle. Studies show that half to 70% of people quit within a year. That’s a big problem because the protection fades fast if you stop. That’s where intravenous (IV) zoledronic acid comes in. Given once a year as a 15-minute infusion, it’s just as effective-or even better-at building bone density. One study showed it improved spine density 4.1% more than risedronate after a year.

And adherence? Nearly perfect. Patients who get an annual IV are far more likely to stick with treatment. In the ZEUS trial, adherence jumped 38% compared to oral pills. It’s especially helpful for older patients, those with memory issues, or anyone who struggles with daily routines. The catch? You need to visit a clinic. And you might feel flu-like symptoms for a day or two after the infusion. But for many, that’s a fair trade-off.

High-Risk Patients: The Case for Teriparatide

Not everyone responds the same way. If you’re over 40, already had a fracture, have a T-score below -2.5, or your FRAX score says you have a 20% or higher chance of a major fracture in the next ten years, you’re in the high-risk group. For these patients, bisphosphonates might not be enough.

That’s where teriparatide (Forteo) comes in. It’s not a bone saver-it’s a bone builder. Unlike bisphosphonates, which slow breakdown, teriparatide actively stimulates new bone growth. It’s a daily injection under the skin, and it’s the only drug proven to reduce vertebral fractures more than bisphosphonates. In the ACTIVE study, only 0.6% of patients on teriparatide had new spine fractures after 18 months, compared to 6.1% on alendronate. That’s a tenfold difference.

The downside? Cost. A month of teriparatide costs about $2,500 in the U.S. Generic bisphosphonates run $250. It’s also limited to two years of use-longer use hasn’t been studied and could raise cancer risk in rare cases. And you can’t use it if you’ve had radiation to the bones, Paget’s disease, or bone cancer. But for someone who’s already broken a bone on steroids? It’s often the best shot.

Monitoring and What Happens Next

Treatment isn’t set-and-forget. You need to track your bone health. A DXA scan-measuring bone density in your spine and hip-is done at the start, then repeated every 12 months. If your bone density drops more than 5% in a year, your treatment plan needs a rethink. Maybe you need to switch from oral to IV, or add teriparatide.

Also, don’t assume you’re safe after a few years. Bisphosphonates can lose effectiveness after 3 to 5 years of continuous use. Some doctors now recommend a “drug holiday”-stopping the drug for a while to let your bones reset. But this isn’t for everyone. If you’re still on high-dose steroids, stopping the drug could mean rapid bone loss. Your doctor will weigh the risks.

The Big Gap: Why So Few People Get Help

Here’s the uncomfortable truth: even though we’ve had solid guidelines since 2001, only about 19% of patients on long-term steroids get the right bone protection within three months. That’s not a failure of science-it’s a failure of systems. Patients don’t always know. Doctors are overwhelmed. Pharmacies don’t remind. And many think, “I feel fine, so my bones must be okay.”

But fractures don’t come with warning signs. They just happen. One moment you’re reaching for a jar, the next you’re in the ER with a crushed vertebra. That’s why prevention isn’t optional-it’s urgent. If you’re on steroids for more than three months, ask for a bone density test. Ask if you’re getting enough calcium and vitamin D. Ask if a bisphosphonate or IV treatment is right for you. Don’t wait for pain. By then, it’s too late.

What’s Coming Next

Research is moving fast. Denosumab (Prolia), given as a shot every six months, is now recommended as an alternative to bisphosphonates for those who can’t tolerate them. It cuts spine fracture risk by nearly 80%. New drugs like abaloparatide, a cousin of teriparatide, are showing even better bone-building results in early trials. And scientists are testing sequences-like starting with teriparatide, then switching to zoledronic acid-to see if we can get even stronger, longer-lasting results.

But for now, the path is clear: start with calcium and vitamin D. Add a bisphosphonate if you’re at risk. Consider IV or teriparatide if you’re high-risk. And never assume you’re fine just because you feel okay. Your bones can’t tell you they’re breaking.