Drugs such as raloxifene, alendronate and risedronate do reduce the risk of fractures of women with osteoporosis, according to the article in the Jan. 19 issue ofBMJ.

"But what they [drug makers] do is to argue that the effect of treating pre-osteoporosis [osteopenia] and osteoporosis is similar," explained study co-author Dr. Pablo Alonso-Coello, a family practitioner at Hospital Sant-Pau in Barcelona. However, many women with osteopenia have such a low risk of fractures that drug treatment would provide almost no benefit, he noted.

"This move to treat pre-osteoporosis raises serious questions about the benefit-risk relationship for low-risk individuals and about the costs of medicalizing and potentially medicating an enormous group of healthy people," the report said. Osteopenia is thought to affect almost half of older women, the study noted.

The study authors looked at four studies, all of which found benefits in giving osteoporosis drugs to women with osteopenia. But those reports exaggerated the benefits, often by reporting risk reduction in relative rather than absolute terms, Alonso-Coello said.

For example, the absolute risk of a woman with osteoporosis having a fracture in a given year might be 10 percent, he said. "The effect of an osteoporosis drug is to lower that risk by half, so the absolute benefit is a 5 percent reduction. But in women with pre-osteoporosis, the risk of fracture is very low, say 1 percent a year, so if you lower that by half, you go down to an 0.5 percent absolute reduction," he explained.

One study cited in the paper claimed a 75 percent relative reduction in the risk of fracture, Alonso-Coello said. The absolute risk reduction was 0.9 percent, meaning that up to 270 women with pre-osteoporosis would have to be treated with drugs for three years to avoid a single fracture.

The study also found that the research played down the potentially harmful side effects of these drugs; in one case, a re-analysis of data on raloxifene, a selective estrogen receptor modulator (SERM), made no mention of the increased risk for blood clots.

Just this month, the U.S. Food and Drug Administration issued an alert on bisphosphonates, the class of osteoporosis drugs that include alendronate and risedronate, warning that the medications can cause severe bone pain.

Even the study authors themselves are open to question, Alonso-Coello said. "Many of the authors are industry people, employees of the drug companies, which casts some doubt on them," he said.

Drug companies now are marketing the drugs in Europe to women with osteopenia, he said. According to the report, two companies had to modify their promotional material after complaints from Alonso-Coello and fellow researcher Ray Moynihan, a conjoint lecturer in the Faculty of Health at the University of Newcastle, Callaghan, New South Wales, Australia.

The World Health Organization is taking steps to help women with osteopenia make decisions about drug treatment. "WHO is moving to calculate absolute risk," Alonso-Coello said. "I contacted them recently and was told they might report really soon, as early as next January. They are working with well-developed equations to calculate the risk of fracture, the same sort of risk factors as for cardiovascular disease."