[Comparative effects of sodium fluoride and hormonal replacement therapy on bone metabolism in osteoporotic women with high fracture risk. Results of monitoring for 2 years].

Thirty seven postmenopausal women aged under 65 with densitometric osteoporosis defined by a bone density value below the 80th percentile of the osteoporotic population but without identifiable crush fractures, were treated and monitored for two years using clinical, laboratory and densitometric parameters. Sixteen of them were given hormonal replacement therapy combining percutaneous or transdermal 17 beta estradiol with a progestogen and the other 21 sodium fluoride at the dose of 50 mg/d combined with calcium and vitamin D. There was a significant increase in vertebral bone density in both groups: 6.3 +/- 0.9 per cent for hormone treatment and 7.1 +/- 1.5% for fluoride after 2 years, while it fell in a control group. The increase was linear with fluoride, while 2/3 of the gain was acquired by the end of the first year of hormonal therapy. Nine of the 16 patients on hormonal therapy and 9 of the 21 taking fluoride showed a significant vertebral gain at 2 years (greater than or equal to 0.043 g/cm2). There was no parameter which enabled the identification of "responders" before treatment. There was no difference in changes in femoral bone density between patients treated with fluoride and controls. From a laboratory standpoint, hormonal therapy caused a significant fall at 12 months in the urinary calcium/urinary creatinine ratio, and a non-significant fall in osteocalcin at 2 years. With fluoride, there was a marked rise in osteocalcin and a more moderate rise in alkaline phosphatase, reflecting stimulation of bone formation without any variation in resorption. In conclusion, this study shows the ability of both these types of treatment of increasing, by different mechanisms, the vertebral bone density of osteoporotic women. However, it does not indicate the extent to which this gain in bone density might have a positive influence on fracture risk.