Evidence for efficacy of drugs affecting bone metabolism in preventing hip fracture.

OBJECTIVE

To examine the effects of taking drugs affecting bone metabolism on the risk of hip fracture in women aged over 50 years.

DESIGN

Retrospective, population based, case-control study by questionnaire.

SETTING

14 centres in six countries in southern Europe.

SUBJECTS

2086 women with hip fracture and 3532 control women matched for age.

MAIN OUTCOME MEASURES

Number of drugs affecting bone metabolism taken and length taken for.

RESULTS

Women taking drugs affecting bone metabolism had a significantly decreased risk of hip fracture. After adjustment for differences in other risk factors, the relative risk of hip fractures was 0.55 (95% confidence interval 0.31 to 0.85) in women taking oestrogens, 0.75 (0.60 to 0.94) in those taking calcium, and 0.69 (0.51 to 0.92) in those taking calcitonin. The fall in risk was not significant for anabolic steroids (0.6 (0.29 to 1.22)). Neither vitamin D nor fluorides were associated with a significant decrease in the risk of hip fracture. The effect on hip fracture risk increased significantly with increasing duration of exposure (risk ratio 0.8 (0.61 to 1.05) for less than median exposure v 0.66 (0.5 to 0.88) for greater than median exposure). Drugs were equally effective in older and younger women, with the exception of oestrogen.

CONCLUSIONS

Oestrogen, calcium, and calcitonins significantly decrease the risk of hip fracture. Short term intervention late in the natural course of osteoporosis may have significant effects on the incidence of hip fracture.