Osteoporotic fractures are increasing as the population ages. Age and female sex are major risk factors for osteoporotic fractures. Hip and vertebral fractures are associated with premature mortality. Osteoporosis risk is assessed by measuring bone mineral density (BMD). See also Chapter 26-16. Normal BMD is no lower than 1.0 standard deviation below the mean for young adult women (T score). Osteopenia is defined as BMD between 1.0 and 2.5 standard deviations below the mean for young adults (T score of –1.0 to –2.5), and osteoporosis is defined as a BMD more than 2.5 standard deviations below the young adult mean (T score below –2.5). Severe osteoporosis is defined as either a T score below –2.5 with a fracture or a T score below –3.5.
The World Health Organization’s Facture Risk Assessment tool (FRAX, available at https://www.shef.ac.uk/FRAX/tool.jsp) can predict a woman’s 10-year risk of having any osteoporotic fracture and the 10-year risk of hip fracture. Risk factors used in the FRAX tool include age, gender, personal history of fracture, parental history of hip fracture, low body mass index, use of oral corticosteroids, secondary osteoporosis, current smoking, and alcohol intake of three or more drinks per day. It can be used with or without BMD. The FRAX tool is particularly helpful in determining which women with osteopenia are most likely to benefit from treatment. Based on the World Health Organization algorithm adopted for the United States, treatment is recommended when there is a 10-year risk of hip fracture of 3% or more or a 10-year risk of a major osteoporotic fracture of 20% or more.
1. Calcium without Vitamin D
Although calcium supplementation is routinely recommended, evidence from the Women’s Health Initiative showed that calcium supplementation did not reduce fracture risk in healthy postmenopausal women, and other research has highlighted potential risks of calcium supplementation.
2. Calcium with Vitamin D
The USPSTF recommendations state that the evidence is insufficient (Grade I) to assess the balance of benefits and harms for the combination of vitamin D and calcium for primary prevention of fractures in men or premenopausal women. For noninstitutionalized postmenopausal women, there is insufficient evidence for daily supplementation with more than 400 international units of vitamin D3 and 1000 mg of calcium; supplementation with less than 400 international units of vitamin D3 and 1000 mg calcium is not recommended. Recommended calcium intake for women younger than 50 years is 1000 mg/day and for women aged 51 and over, it is 1200 mg/day. Dietary calcium is the preferred route for calcium intake because calcium supplements have been associated with an increased risk of myocardial infarction, although there has not been an increase in either cardiovascular or all-cause mortality. Calcium supplements, if they are taken, can be given as either calcium citrate or calcium carbonate and should be combined with vitamin ...