Effects on bone mass after eight years of hormonal replacement therapy

The purpose of this randomised double-blind placebo-controlled study over two years followed by a six year open controlled extension phase was to investigate the effects of hormonal replacement therapy (HRT) both continuous combined HRT and sequential HRT) versus no treatment on lumbar spine bone mineral density (L-BMD) and distal forearm bone mineral content (F-BMC). Further, bone mineral density of the proximal femur, lateral spine, and distal forearm was studied after eight years.

Prospective study of normal, early postmenopausal women, initially in a double-blind, placebo controlled study, subsequently an open, controlled investigation.

Clinical physiology unit of a general second degree referral hospital.

Seventy-three normal, early postmenopausal women (HRT n = .47; placebo/untreated n = 26).

Dual photon absorptiometry, dual X-ray absorptiometry, single photon absorptiometry.

HRT resulted in a significantly (P < 0.001) higher mean L-BMD after eight years, when it was 12.1% higher than the mean initial value and 14.8% higher than the mean bone mineral density of the untreated group. L-BMD increased by 14.6% in women receiving continuous combined HRT compared with 11.1% in those on sequential HRT but intergroup differences were not statistically significant. Mean F-BMC measured with SPA decreased in the HRT group and in the placebo/untreated group by 0.2% and 14.8% (P < 0.001), respectively. However, after eight years mean F-BMC was 14.5% higher in the HRT group than in the placebo/untreated group. The study showed after eight years for all regions of the distal radius and ulna a significantly higher bone mineral density value compared with the placebo/untreated group (P < 0.001). An especially large effect of HRT was found on the bone mineral density of the vertebral body of the 3rd lumbar vertebra (L3), this one, measured by lateral scanning, being 18.7% higher than that of the placebo/untreated group. For the proximal femur, only the bone mineral density of Ward's triangle was significantly higher in the HRT group than in the placebo/untreated group.

Eight years of treatment with HRT resulted in a significant, substantial gain of bone mineral density in the lumbar spine. The distal radius, ulna and Ward's triangle showed a significantly higher bone mineral density in the HRT group compared with the placebo/untreated group.