THE EFFECT OF AGING ON INTACT PTH AND BONE-DENSITY IN WOMEN

Objective: To determine whether age-related bone loss is negatively associated with serum intact parathyroid hormone (PTH). Design: Survey. Setting: University hospital outpatient department. Participants: 100 community-dwelling women, age 18 to 80, recruited as a convenience sample. Measurements: Dependent variables-bone density at the spine and femoral neck by dual-energy X-ray absorptiometry. Independent variables-age, menopausal status (binary) and intact serum PTH by Allegro immunometric assay. Results: Post-menopausal women had higher serum PTH and lower bone density of spine and femoral neck than premenopausal women. Bone density at the spine decreased with age, but this effect was accounted for by menopausal state. Bone density at the femoral neck decreased with age even after adjusting for menopause. Log PTH was negatively associated with bone density at the femoral neck but not significantly at the spine. Multiple regression analysis adjusting for age and menopause showed no significant association between intact PTH and bone density at the spine or the femoral neck. Conclusion: Although this study confirmed the rise in intact PTH with age, there is no evidence that this is the mediator of age-related bone loss.