RESUMEN
The relationship between osteoporosis and primary hyperparathyroidism (pHPT) has not been definitely established because both diseases occur predominantly in postmenopausal women, and because PTH has a paradoxical effect on bone. We have investigated the prevalence of reduced bone mineral density (BMD) in women with pHPT, its relationship with metabolic parameters, and its course after parathyroidectomy. A prospective observational study was carried out on perimenopausal and postmenopausal women consecutively diagnosed and operated on for pHPT. Demographic data were recorded, as well as, PTH, Ca, calciuria/24h, P, vitamin D, adenoma weight. The BMD was measured at three sites: femoral neck (FN), proximal femur (PF), and lumbar spine (LS). Fifty-two patients were included with a mean age of 61+/-12 years. The prevalence of reduced BMD (< or = 1SD, T-score) was 80%-100% depending on site. Parathyroid hormone was higher in patients with osteoporosis (319+/-181 pg/ml) than in those with osteopenia (230+/-83 pg/ml) or normal BMD (148+/-81 pg/ml;p < 0,04). Twenty-eight patients were investigated 1 year after parathyroidectomy. The BMD improved significantly at all sites, particularly in patients with osteoporosis. Age correlated inversely with BMD increases at the femoral sites (r= -0,47;p = 0,02) but not at the LS. 25-OHD3 plasma levels correlated inversely with BMD increases at PF (r= -0,76; p < 0,0001). In pHPT, there is a high prevalence of BMD abnormalities. No metabolic variables had a definite influence on BMD values but a tendency was observed for lower BMD in severe pHPT. One year after parathyroidectomy, there were significant BMD increases that were more marked at femoral sites, in younger patients, in patients with preoperative osteoporosis, and in those with lower plasma levels of 25-OHD3.