US guidelines for the treatment of osteoporosis have been published. The diagnosis of osteoporosis has traditionally been established by the occurrence of fragility fractures or by bone densitometry, which is generally reported in terms of standard deviations (SD) from mean values in young adults (T-score). The World Health Organization (WHO) has defined normal bone mineral density (BMD) for women as a value within one SD of the young adult mean. Values 2.5 SD or more below the mean (T-score -2.5 or below) at the spine, femoral neck, or total hip are defined as osteoporosis. The WHO has developed a computerized model (FRAX) that predicts the 10-year probability of a hip fracture or other major osteoporotic fracture based on clinical risk factors and BMD at the femoral neck.

Osteoporosis is characterized by low bone mass with microarchitectural disruption and skeletal fragility that results in an increased risk of fracture. The diagnosis has traditionally been established by bone densitometry, which is generally reported in terms of standard deviations (SD) from mean values in young adults (T-score). The World Health Organization (WHO) has defined normal bone mineral density (BMD) for women as a value within one SD of the young adult mean. Values 2.5 SD or more below the mean (T score -2.5) are defined as osteoporosis. The WHO has developed a computerized model (FRAX) that predicts the 10-year probability of a hip fracture or any other major osteoporotic fracture based on clinical risk factors and BMD at the femoral neck.

A Medical Letter subscriber was surprised to discover that a new Citracal product contained not only calcium citrate, but also calcium carbonate. Citracal Plus Bone Density Builder actually contains more calcium carbonate per tablet than calcium citrate (240 mg vs. 60 mg). Another Citracal product, Citracal Plus Heart Health, also contains more calcium carbonate than calcium citrate. Many clinicians prefer calcium citrate because it can be taken with or without food, while calcium carbonate must be taken with food for optimal absorption. Other familiar over-the-counter (OTC) names also contain some surprises among their ingredients, as shown in the table below.

>Many well-known brand-name OTC products no longer contain only or necessarily any of their original ingredients.

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Osteoporosis is characterized by low bone mass with microarchitectural disruption and skeletal fragility that results in an increased risk of fracture. The diagnosis has traditionally been established by bone densitometry, which is generally reported in terms of standard deviations (SD) from mean values in young adults (T score). The World Health Organization (WHO) has defined normal bone mineral density (BMD) for women as a value within one SD of the young adult mean. Values 2.5 SD (T score -2.5) or more below the mean are defined as osteoporosis. The WHO has developed a computerized model (FRAX) that predicts the 10-year probability of hip fracture based on clinical risk factors and BMD at the femoral neck.

Many drugs are now marketed for treatment of postmenopausal osteoporosis, but questions remain about their use.

Many drugs are now marketed for treatment of post-menopausal osteoporosis (PD Delmas, Lancet 2002; 359:2018). Prevention of this disorder has been complicated by the news that hormone replacement therapy (HRT), which many women have been taking to prevent osteoporosis, increases the incidence of coronary heart disease and that of breast cancer, stroke and pulmonary embolism as well (Medical Letter 2002; 44:78).

Claims for the superiority of various calcium supplements are now appearing on television and in the print media. A high calcium intake combined with vitamin D can increase bone density and reduce the incidence of fractures in older women and probably also in men.

Many different calcium supplements are promoted for prevention of postmenopausal osteoporosis. Whether a lifelong increase in calcium intake decreases the risk of osteoporosis is unclear, but the results of some clinical trials suggest that it might. Calcium supplementation increased bone mineral density in children and adolescents and, started a few years after menopause, decreased bone loss in postmenopausal women (CC Johnston, Jr et al, N Engl J Med, 327:82, 1992; T Lloyd et al, JAMA, 270:841, 1993; IR Reid et al, AM J Med, 98:331, 1995). Elderly women who took calcium and vitamin D supplements had a lower incidence of hip fractures than those who took placebo (MC Chapuy et al. N Engl J Med, 327:1637, 1992)

Valacyclovir (Valtrex - Glaxo Wellcome), an L- valyl ester of acyclovir (Zovirax), has been approved by the US Food and Drug Administration (FDA) for oral treatment of herpes zoster (shingles) in immunocompetent adults. Famciclovir (Famvir - Medical Letter, 36:97, 1994) is also available for this indication.

Whether a lifelong increase in calcium intake can prevent osteoporosis remains controversial, but many women are now taking calcium supplements on the chance that it might. The typical diet of women in the USA includes less than 600 mg of calcium per day. The National Research Council (NRC) recommends a calcium intake of 1200 mg daily from adolescence through age 24, and 800 mg daily thereafter (Food and Nutrition Board, NRC, Recommended Dietary Allowances, 10th ed, Washington, DC:National Academy Press, 1989, p 174). For mature women, some Medical Letter consultants recommend daily calcium intakes of 1000 mg before menopause and 1500 mg afterward. The effectiveness of estrogen replacement at menopause in preventing postmenopausal bone loss is no longer controversial, and the results of one study suggested that calcium supplementation can lower the effective dosage of estrogen (Committee on Diet and Health, NRC, Diet and Health, Washington, DC:National Academy Press, 1989, p 347).