[The avoidance of early postmenopausal bone substance losses by transdermal estrogen substitution]

The effect of transdermal oestrogen replacement therapy on prevention of osteoporosis was investigated in a controlled randomized study of 38 healthy women (mean age 49.6 [45-54] years) in the early postmenopausal period (< or = 3 years). 19 women (hormone group) continuously used oestrogen patches with a mean daily estradiol delivery of 0.05 mg with addition of medroxyprogesterone acetate, 5 mg orally, for 14 days per month. The other 19 women (calcium group), whose baseline levels were identical, took 500 mg calcium daily. Climacteric symptoms improved significantly in the hormone group, and serum and urinary calcium levels and total serum cholesterol all declined, while the HDL cholesterol levels increased slightly. Bone density was measured by single photon absorptiometry at two points (1/3 and 1/10 of the forearm length from the distal end of the radius). After 6 and 12 months, the values at the proximal site (1/3) had risen in the hormone group by 1.1% and 0.46% and had fallen in the calcium group by 1.96% and 2.42% respectively (both P < 0.05 vs hormone group). At the distal radial site (1/10), the values increased by 2.14% and 5.3% in the same period and fell by 3.59% and 5.67% in the calcium group. The overall difference after 12 months was 11% (P < 0.01). Transdermal oestrogen appears to be as effective as oral oestrogen replacement for prevention of osteoporosis, and should help to prevent vertebral and limb fractures in the elderly.