2 Osteoporosis

How osteoporosis affects bone

Osteoporosis weakens bones and increases the chance of fracture. It often causes no symptoms until a fracture occurs. Although it is more common in women, men—especially older men—can also develop it.

Factors that increase risk

Risk increases with older age and low body weight. Other risk factors include smoking, physical inactivity, a parent’s history of hip fracture, some medical conditions, and certain medications, including long-term glucocorticoid use.

Risk factors can occur together. For example, older age, low body weight, smoking, inactivity, long-term glucocorticoid use, and a family history of hip fracture each contribute to the risk profile.

Prevention and bone health

Bone and muscle health benefit from regular physical activity, including weight-bearing and strength exercises. Balance work and fall-prevention measures can help reduce injury risk.

A nutritious diet should provide adequate calcium and vitamin D. Supplements may be considered when needed to meet individual requirements; they are not a universal substitute for calcium-rich foods. Avoiding smoking, limiting heavy alcohol use, and reducing fall hazards are also part of prevention.

Who should be screened

For people without known osteoporosis or a prior fragility fracture, the U.S. Preventive Services Task Force recommends screening women aged 65 or older. It also recommends assessing postmenopausal women younger than 65 for risk and screening those at increased risk.

For men, evidence is insufficient to determine the balance of benefits and harms of routine screening. Clinicians may use clinical judgment. These recommendations do not cover people with a prior fragility fracture or certain secondary causes of bone loss.

Understanding bone-density results

DXA measures bone density, commonly at the hip and spine. For postmenopausal women and men aged 50 or older, a T-score of $−2.5$ or lower is in the osteoporosis range. A T-score between $−1.0$ and $−2.5$ indicates osteopenia, or low bone density; it is not normal bone density.

A clinician interprets the result alongside fracture history and other risk factors. A bone-density result is one part of assessing a person’s fracture risk.

Using fracture risk to guide decisions

FRAX estimates 10-year fracture probability. For adults with osteopenia, U.S. treatment guidance commonly considers medication when the estimated 10-year probability is at least $3\%$ for hip fracture or at least $20\%$ for a major osteoporotic fracture.

These thresholds support, but do not replace, individual clinical decision-making. A low bone-density result and an elevated fracture-risk estimate warrant discussion with a clinician; medication is not considered only when the T-score is $−2.5$ or lower.

Individualized treatment

Treatment aims to prevent fractures and is individualized. It may combine adequate nutrition, physical activity, fall prevention, and prescription medication. Bisphosphonates are among the medications used to preserve bone density and treat osteoporosis.

Medication choice depends on the person’s fracture risk and health conditions, along with clinician assessment. Lifestyle changes alone are not always enough, and the same medication is not necessarily appropriate for everyone.