Patients who take statins seem to be less likely to suffer fractures, even when they have only taken the drugs for a relatively short time, according to the findings of two studies and a "research letter".
In the first study, Dr Christoph Meier (division of clinical pharmacology, University hospital of Basel, Switzerland) and colleagues report that patients aged over 50 years, who had been or were being treated with a statin, were less likely to suffer fractures than those who had never been given the drugs.
The protective effect was mainly seen in patients currently taking the drugs and the authors suggest that it could be detected after treatment for between one and four months.
Patients who were taking fibrates, or lipid-lowering agents that were neither statins nor fibrates, did not appear to be protected from fractures.
"The findings of this. . . analysis indicate that exposure to statins is associated with a substantially lower risk of developing fractures in humans. The association. . . could be identified even after relatively short exposure duration," they say.
The analysis involved 3,940 fracture patients from the UK-based General Practice Research Database. The authors compared the rate of fracture in those taking lipid-lowering drugs with that seen in a control group.
The adjusted odds ratios of suffering a fracture for current, recent or past exposure to statins, regardless of the number of prescriptions, were 0.55 (95 per cent confidence intervals 0.44-0.69), 0.67 (0.5-0.92) and 0.87 (0.65-1.18), respectively. In contrast, the figures for those who took fibrates were 0.87 (0.7-1.08), 1.05 (0.79-1.41) and 0.85 (0.64-1.13). For those patients who were taking lipid-lowering agents that were not statins or fibrates, the figures were 0.76 (0.41-1.39), 1.19 (0.66-2.14) and 0.97 (0.71-1.34).
This showed that the risk of fracture was reduced with statins but there was little evidence that fibrates or other lipid-lowering drugs had such an effect, they say (Journal of the American Medical Association 2000;283:3205).
These results are confirmed by a US study, which found that women taking statins were less likely to suffer fractures. The authors conclude that the drugs should be considered as a treatment option in osteoporosis (Lancet 2000;355:2185).
Dr K. Arnold Chan (department of medicine, Harvard medical school) and colleagues investigated 928 cases of women aged over 60 who had suffered a fracture, and 2,747 controls. They found that the adjusted odds ratio for fracture in women who had had 13 or more "statin dispensings" (defined as the dispensing of a prescription for treatment for 30 days or more) during the previous two years was 0.48 (0.27-0.83).
There was no significant reduction in risk with fewer than 13 statin dispensings or with the use of non-statin lipid-lowering agents, they say.
Commenting on the results, Dr Chan and colleagues say: "Regular statin use during a two-year period was associated with a more than 50 per cent reduction in fracture risk."
The results do not indicate the minimum dose or duration of statin use that confers protection against osteoporosis but the authors suggest that at least a year of continuous exposure is required.
In the research letter (ibid 2000;355:2219), Dr C. Edwards and colleagues say that the exact mechanism of action of statins in preventing fracture is unclear but that they may decrease production of mevalonate, a precursor of cholesterol production.
This pathway is important in the action of bisphosphonates, which are used to treat osteoporosis, they say.
The authors compared the bone-mineral density at the spine and hip of 41 women who had been taking statins for a median period of 48 (9-78) months with that of 100 controls. They found that the bone-mineral density of the statin users was significantly higher than that of the controls.
"Our findings may have major implications for the design of future treatments for osteoporosis," they say.