How to Prevent Steroid-Induced Osteoporosis: Calcium, Vitamin D, and Bisphosphonates Explained

When you’re on long-term steroids-whether for asthma, rheumatoid arthritis, or an autoimmune condition-you’re not just managing inflammation. You’re also quietly putting your bones at risk. Steroid-induced osteoporosis isn’t a slow, distant threat. It can start within three to six months of starting treatment. And if you’re taking just 5 mg of prednisone a day or more, your fracture risk can jump up to 17 times higher than someone not on steroids. The scary part? Most people don’t even know it’s happening until they break a bone.

Why Steroids Attack Your Bones

Steroids don’t just calm your immune system. They mess with how your bones rebuild themselves. Your skeleton is always changing-old bone breaks down, new bone forms. That’s called remodeling. Steroids throw this process out of balance. They shut down the cells that build bone (osteoblasts), cutting bone formation by up to 70%. At the same time, they crank up the cells that break bone down (osteoclasts), increasing resorption by about 30%. The result? Your bones get thinner, weaker, and more likely to snap-even from something as simple as a fall or a cough.

This isn’t just a problem for older adults. Even someone in their 30s or 40s on long-term steroids can lose bone density fast. And unlike regular osteoporosis, which develops over years, steroid-induced bone loss can be dramatic within the first year. Studies show that 12% of people taking 7.5 mg or more of prednisone daily will have a spine fracture within 12 months.

Step One: Calcium and Vitamin D-The Foundation

Before you even think about pills that stop bone loss, you need to give your bones the raw materials to stay strong. That means calcium and vitamin D. No exceptions. No "I’ll just eat more dairy." You need precise amounts.

The American College of Rheumatology says everyone starting long-term steroids (3 months or longer at 2.5 mg prednisone or more) should take 1,000 to 1,200 mg of calcium daily. That’s not a suggestion-it’s a requirement. You can get it from food-yogurt, cheese, fortified plant milks, leafy greens-but most people need supplements to hit that target.

Vitamin D is just as critical. Your body needs it to absorb calcium. Without enough, calcium just passes through you. The guidelines recommend 600 to 800 IU per day. But if your blood test shows vitamin D below 30 ng/mL (which is common, especially in winter), you’ll need 800 to 1,000 IU daily. Some people need even more, especially if they’re older, overweight, or have darker skin. A simple blood test can tell you where you stand.

Don’t skip this step. Even if you take a powerful drug later, without calcium and vitamin D, it won’t work as well. Think of it like trying to build a house without bricks. The tools matter-but you still need the materials.

Step Two: Bisphosphonates-The First-Line Defense

If you’re on steroids long-term and you’re 40 or older, or you’ve had a fracture before, you need more than supplements. You need a medication that stops bone loss. That’s where bisphosphonates come in.

These are the most studied, most proven drugs for steroid-induced bone loss. Alendronate (Fosamax) and risedronate (Actonel) are the most common. Both are taken once a week. They work by slowing down the bone-breakers (osteoclasts). In clinical trials, alendronate increased spine bone density by 3.7% in just one year-while the placebo group lost bone. Risedronate cut vertebral fracture risk by nearly 70%.

They’re not perfect. You have to take them right. Take them first thing in the morning, on an empty stomach, with a full glass of water. Stay upright for at least 30 minutes. Don’t lie down. Don’t eat or drink anything else for 30 minutes. Skip this, and you risk serious irritation to your esophagus. About 1 in 5 people have trouble with this. That’s why many switch to the yearly IV version: zoledronic acid.

Zoledronic acid is given once a year as a 15-minute infusion. It’s more effective than oral versions at preserving hip bone density and improves adherence-because you don’t have to remember a weekly pill. In one study, patients on zoledronic acid had 41% fewer hip fractures compared to placebo. It’s also safer for people with kidney issues, as long as their kidney function isn’t severely low.

When Bisphosphonates Aren’t Enough

Not everyone responds the same. If you’ve already had a fracture, your T-score is below -2.5, or you’re on high-dose steroids for more than a year, bisphosphonates might not be enough. That’s when doctors turn to teriparatide (Forteo).

Teriparatide is different. Instead of slowing bone loss, it actually builds new bone. It’s a synthetic version of part of your natural parathyroid hormone. You inject it daily under the skin. It’s expensive-about $2,500 a month-and only approved for two years of use. But in the ACTIVE study, it cut new spine fractures from 6.1% to just 0.6% compared to alendronate. That’s a massive difference.

It’s not for everyone. You can’t use it if you’ve had radiation to your bones, Paget’s disease, or bone cancer. And while it’s safe in humans, there’s a black box warning because it caused bone tumors in rats. But after 15 years of real-world use, no such risk has been found in people.

Another option is denosumab (Prolia), given as a shot every six months. It reduces spine fracture risk by 79%. It’s great for people who can’t take bisphosphonates due to kidney problems or stomach issues. But it has a catch: if you stop it, you can lose bone fast. So you can’t just quit-it needs to be replaced with another drug, like a bisphosphonate.

Who Gets Treatment-and Who Doesn’t

Here’s the hard truth: most people on steroids don’t get the bone protection they need. A 2021 study of over 150,000 patients found only 19% received any kind of osteoporosis prevention within three months of starting steroids. That’s not because doctors don’t know better. It’s because the system fails. Patients don’t get tested. They don’t get warned. They don’t get follow-up.

The guidelines are clear. If you’re 40 or older and taking ≥2.5 mg prednisone daily for ≥3 months, you should get a bone density scan (DXA) and start treatment. If you’re under 40 but have had a fracture before, or you smoke, have low body weight, or take other bone-weakening drugs, you still qualify.

But here’s what many don’t realize: you need to get scanned again after one year. If your bone density drops more than 5%, you need to switch or upgrade your treatment. Many people get one scan and think they’re done. They’re not.

What to Watch Out For

No drug is without risk. Bisphosphonates carry a tiny chance of atypical femur fractures-about 1 in 10,000 people per year. That’s rare, but real. If you get new thigh or groin pain that doesn’t go away, tell your doctor. It could be a warning sign.

Another rare issue is osteonecrosis of the jaw-bone death in the jaw. It’s extremely uncommon with oral bisphosphonates (less than 1 in 10,000), but more likely if you’re getting dental work while on the drug. Always tell your dentist you’re on steroids and a bisphosphonate. They may delay major procedures until you’ve been off the drug for a while.

Teriparatide’s main risk is its cost and the fact that you can only use it for two years. After that, you need to switch to something else-usually a bisphosphonate-to keep the gains.

What’s Next? The Future of Bone Protection

New drugs are coming. Abaloparatide, approved in 2022, is similar to teriparatide but may build bone even better. And researchers are now testing sequences: start with teriparatide to rebuild, then switch to zoledronic acid to maintain. Early results suggest this combo could give you more bone density than either drug alone.

But for now, the best approach is still simple: start early, use what works, and stick with it. Calcium and vitamin D are non-negotiable. Bisphosphonates are the go-to for most people. Teriparatide is the upgrade for those at highest risk. And regular monitoring? That’s your safety net.

Don’t wait for a fracture to realize your bones are in trouble. If you’re on steroids, talk to your doctor now. Get your bone density tested. Start the right supplements. Ask if you need a bisphosphonate. It’s not just about feeling well-it’s about staying strong enough to live well for years to come.