Calculations based on risk factors. In a comparison of strategies using risk factors to predict low BMD in postmenopausal women, 2 decision rules performed well: the Osteoporosis Risk Assessment Instrument, which is based on age and weight (Table 1),17 and the Simple Calculated Osteoporosis Risk Estimation (SCORE).17 Research to test these instruments with fracture rather than BMD as outcome is needed.18
Biochemical markers. Levels of markers in serum and/or urine reflect bone turnover and have potential use in diagnosing and monitoring therapy of osteoporosis. They are not yet widely available and have not been consistently associated with identifying patients at risk for fracture.10 They are not recommended at this time.
Patients with a score of 9 or higher are at risk for diagnosis of osteoporosis by bone mineral density measurement. Sensitivity 97.5%, specificity 28%, positive predictive value 28%, negative predictive value 99.6%, given a 10% baseline risk of a bone mineral density 2.5 SD less than the mean.
Importance of primary prevention
At least half of bone strength is attributable to genetic factors12; modifiable factors may contribute almost equally as a group, and therefore warrant attention. Genetic risk factors include age, family history, female sex, low weight, small frame, and white or Asian race. Primary prevention efforts should begin in childhood and continue throughout the life span to maximize bone mass.3
Prevention efforts that target the modifiable factors described below should be a routine part of the health-maintenance visit.
Fall reduction
Falls are the direct cause of more than 90% of osteoporotic hip fractures,19 and the tendency to fall increases with age. Some studies have shown that, for women over age 70, the most important predictors of hip fractures are fall-related factors20,21 such as poor cognitive function, slow gait and otherwise impaired mobility, poor vision, drugs that impair alertness or balance, and history of falls. In women over 75, age and slow gait are equal to low BMD of the femoral neck as predictors of hip fracture.22 Unfortunately, labeling women as osteopenic or osteoporotic can cause fear of falling and lack of activity, leading to further acceleration of bone loss.10
Medications that interfere with balance or alertness should be avoided if possible. Environmental hazards such as loose rugs and uneven or slippery surfaces are also well-recognized modifiable risks for falls23,24 that should be eliminated. Hip protectors effectively reduce fractures in the frail elderly25 and can boost confidence for beneficial increases in physical activity levels,26 but they are often poorly accepted by patients.25,27 Other options include referral for gait training, home visits by a physician or nurse to identify problems in the home that increase the risk of falls, or providing information on home modification (such as installing bathtub rails, removing throw rugs, etc.).
Improvement of nutritional intake
Adequate consumption of calcium is essential for bone health. Calcium balance also can be adversely affected by dietary habits, including high intake of protein, phosphorus, and sodium, although these effects appear to be less important when dietary calcium is sufficient.3 The recommended calcium intake for postmenopausal women (1200–1500 mg/day)28 can be met with food sources, but supplements should be added if needed. Most postmenopausal women in the United States consume only about 600 mg/day.28 High-calcium foods include milk (290–300 mg/cup), sardines in oil, with bones (370 mg/3 oz), yogurt (300–500 mg depending on container size), cheese (165–270 mg/slice), canned salmon, with bones (170–210 mg/3 oz), broccoli (160–180 mg/cup), and tofu (144–155 mg/4 oz).15
Vitamin D is essential for intestinal absorption of calcium. The recommended intake for women is 400 IU/day for ages 51 to 70, 600 IU/day over age 70, and 800 IU/day for all high-risk women, including those who are homebound, institutionalized, on chronic glucocorticoids, or who live in northern latitudes and therefore have limited exposure to sunlight.29 Sources of vitamin D include sunlight, vitamin D–fortified foods, fish oils, and supplements. Multivitamins typically contain 400 IU of vitamin D.
Phytoestrogens, particularly in the form of soy products, have received attention for bone health. Overall, studies do not support the use of soy foods to prevent osteoporosis.3 A well-designed trial in postmenopausal women found that ipriflavone, a synthetic phytoestrogen, did not decrease bone loss.30 Furthermore, use was associated with subclinical lymphocytopenia.
Regular exercise
Weight-bearing physical activity such as walking or running in early life contributes to higher peak bone mass. Limited data suggest weight-bearing exercise in postmenopausal women produces small increases in bone density at the hip31 and improvement in balance and strength.32 For women with established osteoporosis, activities that place an anterior load on the vertebral bodies, such as forward flexion exercises, are associated with an increased incidence of new vertebral deformities, and patients should be advised to avoid them.33
