Bone density

What does bone density mean?

Bone density measures mineral content. Lower density raises fracture risk, but cannot predict fractures on its own. 1

Why does it decline?

Aging and menopause contribute to bone loss. Inactivity and prolonged corticosteroid use are additional risk factors. 1

Can you feel bone loss?

Osteoporosis is often unnoticed until a fracture. A fracture after a fall from standing height can prompt assessment. 1

What does the scan tell you?

A DXA scan compares bone density with that of a healthy young adult. The difference is expressed as a T-score. Clinicians combine the scan with age, sex and other risk factors when considering treatment: the goal is to prevent fractures, rather than simply improve a number. 2

Which other causes matter?

Bone loss can also accompany malabsorption or hormone-related conditions. A family history of hip fracture, low body weight and some medicines are relevant when assessing risk. 2

Does calcium improve bone density?

Reviews report increases in bone density with calcium, alone or with vitamin D, in older adults. The clinical importance is uncertain, and fracture results conflict. 3

Calcium with vitamin DMixed

Benefits vary by study and outcome; improved density does not establish fewer fractures. 3

What did randomized trials find?

Tai and colleagues reviewed 59 randomized trials in adults over 50. Calcium supplements increased density by 0.7% to 1.8%, with similar gains at later follow-up to those at one year. Food-based calcium produced comparable small changes at most measured sites. The authors judged these non-progressive gains unlikely to produce a clinically important reduction in fractures. Trials with higher calcium doses did not show clearly greater density gains. 4

Does vitamin D alone build stronger bones?

A review of 23 trials included 4,082 adults, mostly women, followed for an average of 23.5 months. Vitamin D produced a small 0.8% gain at the femoral neck, but no benefit at other measured sites. The authors questioned routine osteoporosis prevention in community-dwelling adults without deficiency risk factors; this does not settle treatment of deficiency. 5

Vitamin DMixed

Small, site-specific benefit; no consistent increase across the skeleton. 5

What matters besides pills?

Physical activity, balance training and fall prevention address risks that a density measurement does not capture. 1

Questions people ask