RESUMEN
The beneficial skeletal effects of menopausal estrogen replacement therapy (HRT) are well documented. The role of secondary mineralization of bone as a determinant of bone quality is now well established in postmenopausal women treated with bisphosphonates or SERMs. The aim of present study was to investigate the effect of conventional and high doses of estrogen on the main parameters reflecting the degree of mineralization of bone (DMB). Bone biopsies were obtained from 20 women with osteopenia or osteoporosis before and after 24 months (18 to 38 months) of conventional HRT, and from 19 women who had received high doses of estradiol (implant 100 mg every 3-6 months for 1.5-20 years). DMB parameters (mean DMB, DMB Freq. Max. and Heterogeneity Index of the individual distributions of DMB) were measured using quantitative microradiography in cortical, cancellous, and total bone and expressed as g mineral/cm(3) bone. Values obtained in women before HRT were lower than those reported in pre- and postmenopausal control women. After conventional HRT, there was an increase in mean DMB (total bone) of 4.4 +/- 1.9% (mean +/- SEM) versus pre-treatment values (4.1 +/- 2.1% in cortical bone, 4.5 +/- 2.3% in cancellous bone); these differences did not reach statistical significance (P = 0.055). Results were similar for DMB Freq. Max. but Heterogeneity Index was not significantly changed. After high dose estradiol therapy, mean DMB (total bone) was 6.9 +/- 1.9% higher than in untreated women (8.6 +/- 2.1% in cortical bone, 6.5 +/- 2.1% in cancellous bone); this difference was statistically significant (P = 0.03). Results were similar for DMB Freq. Max. but once again Heterogeneity Index was not significantly modified. The increases in mean DMB were due to a shift of the curves towards high DMB with a decrease of the low DMB values, as confirmed by the absence of changes in the Heterogeneity Index. Estrogen therapy is associated with an increased degree of mineralization of bone induced by a prolongation of secondary mineralization, similar to that observed with other antiresorptive agents. However, this increase was about two-fold lower than that observed after alendronate therapy (10 mg/day/3 years) in postmenopausal osteoporotic women.
Asunto(s)
Calcificación Fisiológica/efectos de los fármacos , Terapia de Reemplazo de Estrógeno/métodos , Ilion/efectos de los fármacos , Ilion/diagnóstico por imagen , Osteoporosis Posmenopáusica/diagnóstico por imagen , Osteoporosis Posmenopáusica/tratamiento farmacológico , Anciano , Calcificación Fisiológica/fisiología , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Estrógenos/administración & dosificación , Femenino , Humanos , Microrradiografía/métodos , Persona de Mediana EdadRESUMEN
Raised levels of parathyroid hormones (PTH) predispose to osteoporotic fracture particularly in the elderly. The true prevalence of primary or secondary hyperparathyroidism is unknown, as PTH evaluation is not performed as a screening test in the elderly. We report raised PTH levels in 27 of 190 (14.2%) community living fully mobile postmenopausal women with densitometrically established osteopenia, consuming an average of 645 (+/-191) mg of calcium per day. Twenty-five of the 27 women with raised PTH were normocalcaemic, hypercalcaemia been found only in two. Serum 25 hydroxy vitamin D levels were all within the normal range (above 22 nmol/l). Women with a raised PTH were significantly older and their serum 25 hydroxy vitamin D levels were significantly lower than those women with normal PTH values. These data suggest that in community leaving healthy postmenopausal women, normocalcaemic hyperparathyroidism, in the presence of what are still considered normal vitamin D levels, may be common. This may suggests that widespread supplementation with calcium and vitamin D may be required in postmenopausal women for PTH suppression and preservation of bone mass.