The Role of Parathyroid Hormone on the Pathogenesis of Osteoporosis in the Aged Females

Abstract

In order to evaluate the role of parathyroid hormone (PTH) on the pathogenesis of osteoporosis in the aged female, we have investigated the relationship between serum level of PTH and radial mineral content (RMC) in 224 elderly female aged over 60 years old. In accordance with their serum levels of PTH, the subjects were divided into three groups; Group 1 whose serum PTH levels were less than 0.16ng/ml, Group 2 whose serum PTH levels were ranged from 0.16 to 0.55ng/ml, Group 3 whose serum PTH levels were more than 0.55ng/ml. Mean age, serum Ca, P, Al-P and BUN levels were not significantly different in the three groups. No significant differences in mean values of daily urinary Ca and P excretion were also found. However, the mean value of urinary hydroxyproline excretion in Group 1 and 3 were significantly higher than that in Group 2. The mean serum levels of 25-OHD in Group 1(17.8±1.7ng/ml) and 3(17.5±1.2ng/ml) were significantly lower than that in group 2(22.0±1.0ng/ml). The mean serum levels of 1, 25 (OH)₂D in Group 1(21.8±4.5pg/ml) was significantly lower than that in Group 2(36.4±1.8 pg/ml). The values of RMC in Group 1 and 3(0.40±0.01 and 0.38±0.01g/cm², respectively) were significantly lower than that in Group 2(0.44±0.01g/cm²). Moreover, the incidences of vertebral fracture(s) in Group 1 and 3(35.0% and 38.5%, respectively) were also significantly higher than that in Group 1 (16.7%). In conclusion, either high and low circulating PTH level might be cosidered as a risk factor for the development of osteoporosis in the aged females. The role of PTH on the pathogenesis of osteoporosis in the aged female was different in osteoporotic patients with high circulating levels of PTH and those with low PTH levels.