Osteopenia

Osteopenia means bone density is lower than average but not low enough to count as osteoporosis. It is common with aging, especially after menopause. It causes no symptoms. Risk factors include female sex, older age, low body weight, smoking, heavy alcohol use, low calcium or vitamin D, low activity, long-term steroid use, early menopause, and conditions such as celiac disease, rheumatoid arthritis and an overactive thyroid or parathyroid. Not everyone with osteopenia goes on to have fractures. Fracture risk depends on bone density together with other risk factors.

Lab tests linked to osteopenia:

• C-telopeptide (CTX), serum: a marker of bone breakdown. It is sometimes used to monitor treatment, not to diagnose osteopenia.
• Osteopenia is diagnosed with a DXA bone density scan. Doctors may also order calcium, vitamin D, kidney function, alkaline phosphatase, parathyroid hormone, TSH and, in men, testosterone, to look for secondary causes.

How results are read:

• In postmenopausal women and men aged 50 or older, a DXA T-score below -1.0 but above -2.5 indicates osteopenia, and -2.5 or lower indicates osteoporosis. Younger adults are usually assessed with Z-scores and clinical context.
• Fracture risk tools, such as FRAX, combine bone density with age and other risk factors to help decide whether treatment is needed.
• CTX should be measured in the morning while fasting, because it varies through the day and after eating. With treatment that slows bone breakdown, a meaningful fall in CTX can support a treatment response. The expected change depends on the medicine and on consistent sampling conditions.
• Low vitamin D, high calcium or high parathyroid hormone point to treatable causes of bone loss.

When to see a doctor:

• Ask about a bone density scan if you are a woman aged 65 or older, or younger with risk factors, or if you have broken a bone from a minor fall.
• See a doctor about loss of height or a new curve in the upper back.

Clinical takeaway: osteopenia is diagnosed with a DXA scan, blood tests look for secondary causes, and CTX is used mainly to monitor treatment.