Under the auspices of the World Health Organization (WHO), a panel of experts has periodically met on the topic of assessment of fracture risk and osteoporosis.
The World Health Organization first convened a group of experts in 1994 to assess fracture risk and its application to screening for postmenopausal osteoporosis. The scientific group defined osteoporosis based on bone mineral density (BMD). A standardized score, called T-score, comparing BMD to average values for young healthy women is used to define the categories.
The categories for diagnosis are:
- normal (T-score -1.0 and above)
- low bone mass, referred to as osteopenia (T-score between -1.0 and -2.5)
- osteoporosis (T-score -2.5 and below)
- severe osteoporosis (T-score -2.5 and below with history of a fracture)
These criterion applied only to white postmenopausal women since the research data was primarily limited to this group. In addition, diagnosis could only be based on three skeletal sites of measurement: lumbar spine, hip, or forearm.
Advances in research demonstrated limitations in the original definition. Defining fracture risk by BMD alone did not capture the majority of people at risk for breaking a bone. In addition, studies of men and nonwhite women provided estimates of fracture risk in these populations.
In 2004, another scientific group met to reevaluate the assessment of osteoporosis. After rigorous scientific study and debate, a revised description of osteopenia and assessment of osteoporosis was released in 2008.
The revised assessment includes BMD with selected risk factors for fracture along with height and weight. A fracture risk score, called FRAX, is calculated to determine your 10-year probability of fracture. Two scores are given: probability of hip fracture and the other for a major osteoporotic fracture, defined as wrist, shoulder, hip, or painful spine fractures.
Countries have set different criteria for when treatment with osteoporosis medicines is recommended. In the United States, the National Osteoporosis Foundation (NOF) released new guidelines at the same time as WHO-2. Treatment guidelines were established based on fracture risk and a cost-effective model for lowering risk with use of osteoporosis medicines. The guidelines for treatment are for postmenopausal women of any race or ethnicity and men age 50 and over.
Three major categories are defined as high-risk groups that should consider treatment with FDA-approved medicines to lower their risk:
- History of fracture of the hip or spine
- Bone mineral density in the osteoporosis range (T-score of -2.5 or lower)
- Bone mineral density in the low bone mass or osteopenia range with a higher risk of fracture defined by FRAX score for
- Major osteoporotic fracture 10-year probability of 20% or higher OR
- Hip fracture 10-year probability 3% or higher