Most osteoporosis is labelled "primary" — it's the result of aging and hormonal changes. But in a significant number of Canadians, bone loss is driven by an underlying disease or medication. This is called secondary osteoporosis, and treating only the bones without addressing the root cause won't be enough.
Secondary osteoporosis means bone loss is being caused or significantly accelerated by a specific identifiable condition — not just age and genetics. It accounts for roughly 20–30% of osteoporosis cases in women and up to 50% in men. Because many of the underlying conditions are common, secondary osteoporosis is far more prevalent than most people realize.
The key question every person with osteoporosis should ask (and every doctor should investigate) is: "Is there an underlying cause that's driving my bone loss?" A thorough workup typically includes blood tests to check calcium, vitamin D, thyroid function, parathyroid hormone, kidney function, and in men, testosterone.
Celiac disease damages the small intestine's ability to absorb nutrients — including calcium and vitamin D, the two most critical nutrients for bone health. Even people with mild or "silent" celiac disease often have significantly reduced bone density. A strict gluten-free diet substantially improves absorption and can partially restore bone density, but supplementation with calcium and vitamin D is nearly always necessary, and many people will need osteoporosis medication.
If you've been diagnosed with celiac disease, request a DEXA scan from your gastroenterologist or family doctor. Most provinces will cover this. See our DEXA scan guide for what to expect.
Both Crohn's disease and ulcerative colitis increase fracture risk through multiple mechanisms: malabsorption of calcium and vitamin D, chronic inflammation (inflammatory cytokines directly suppress bone formation), frequent corticosteroid use, and sometimes low body weight. Studies show that up to 60% of people with IBD have osteopenia or osteoporosis.
The Crohn's and Colitis Canada organization recommends that all IBD patients discuss bone health with their gastroenterologist. DEXA scans are often indicated at diagnosis or after significant corticosteroid exposure.
Rheumatoid arthritis causes bone loss through two main pathways: systemic inflammation and the medications used to treat it (primarily corticosteroids). Even patients whose RA is well-controlled have elevated fracture risk. Biologic therapies for RA (TNF inhibitors) appear to partially protect against bone loss compared to steroids, but they don't eliminate the risk.
The Canadian Rheumatology Association recommends that all RA patients be assessed for osteoporosis risk, especially those on long-term corticosteroids.
Glucocorticoids (prednisone, prednisolone, dexamethasone) are among the most common drug-induced causes of bone loss. Corticosteroids directly suppress bone formation, increase calcium excretion through the kidneys, and reduce intestinal calcium absorption. Bone loss is fastest in the first 6–12 months of treatment.
The threshold for concern: more than 7.5mg prednisone (or equivalent) daily for more than 3 months. At this level, Osteoporosis Canada guidelines recommend:
Inhaled corticosteroids for asthma also carry a dose-dependent bone risk, though much lower than oral steroids.
Excess thyroid hormone — whether from hyperthyroidism (overactive thyroid) or over-replacement with levothyroxine — accelerates bone remodeling and can cause net bone loss. People on thyroid hormone replacement for hypothyroidism need to ensure their TSH level isn't suppressed below normal; over-treatment with levothyroxine is a common and underrecognized cause of bone loss.
If you're on thyroid medication, ask your doctor to confirm your TSH is in the therapeutic range. Annual TSH testing is standard.
People with Type 1 diabetes have lower bone density and higher fracture risk than the general population, despite relatively normal or even increased bone mineral density in some measurements. The mechanism isn't fully understood but likely involves insulin's role in bone metabolism and accumulation of advanced glycation end products (AGEs) in bone collagen, which impair bone quality independent of density.
Chronic obstructive pulmonary disease (COPD) is associated with significantly increased osteoporosis risk — and it's underrecognized. Causes include smoking (a major risk factor for both), systemic inflammation, low physical activity, low body weight, and repeated corticosteroid courses. Studies suggest 35–60% of people with COPD have osteoporosis or osteopenia. DEXA screening is appropriate for most COPD patients over 50.
Primary hyperparathyroidism — when one or more parathyroid glands become overactive — causes the body to continuously pull calcium from bone. It's diagnosed by finding elevated blood calcium with elevated or inappropriately normal PTH (parathyroid hormone). It's more common than people realize, particularly in postmenopausal women. Surgery to remove the overactive gland can partially reverse bone loss.
| Condition | Primary Mechanism | DEXA Recommended? |
|---|---|---|
| Celiac disease | Calcium/vitamin D malabsorption | Yes — at diagnosis |
| Crohn's / IBD | Malabsorption + inflammation + steroids | Yes — at diagnosis or with steroid use |
| Rheumatoid arthritis | Inflammation + corticosteroids | Yes |
| Corticosteroid use ≥3 months | Direct bone suppression | Yes — baseline + annual |
| Hyperthyroidism / TSH suppression | Accelerated bone turnover | Yes |
| Type 1 diabetes | Insulin / bone quality impairment | Yes — particularly with long duration |
| COPD | Smoking + inflammation + steroids | Yes — particularly age 50+ |
| Primary hyperparathyroidism | Continuous bone calcium resorption | Yes |
When someone is diagnosed with osteoporosis, especially if they're younger than expected (under 65), or if bone loss is more severe than expected, doctors should run a secondary causes workup. This typically includes:
If your doctor hasn't ordered these tests after diagnosing you with osteoporosis, ask about them — particularly if you're young, male, or have any of the conditions listed above.
Treating secondary osteoporosis means addressing both the underlying condition and the bone loss directly. For example:
Most osteoporosis medications (bisphosphonates, denosumab) are effective regardless of the cause of bone loss. See our guide to osteoporosis medications in Canada for coverage details and options.
If you have any of the conditions listed above, be proactive: