The short term effects of tamoxifen on bone turnover in older women.

Abstract

This study examined the effects of tamoxifen (TAM) on biochemical markers of bone turnover in healthy women, 20-30 yr past menopause. Ten women (mean age, 75 yr; range, 70-85 yr) were given TAM (20 mg/day) for 10 weeks. Serum and urine were collected twice at baseline, at weeks 9 and 10 of TAM treatment, and at weeks 9 and 10 post-TAM. Markers of bone formation were serum osteocalcin, total alkaline phosphatase, bone-specific alkaline phosphatase, and type I procollagen peptide. Markers of bone resorption were fasting urinary calcium, hydroxyproline, pyridinoline, and deoxypyridinoline, all corrected for urinary creatinine. Total cholesterol, triglycerides, and high density lipoproteins were measured; low density lipoprotein levels were calculated. Pyridinoline and deoxypyridinoline decreased during therapy by 23% and 25% and returned to baseline posttherapy (F = 37.01; P = 0.001), with no significant changes in urinary calcium and hydroxyproline. Markers of bone formation declined 17-36%, with a variable return toward baseline (F = 85.56; P < 0.001). Ionized calcium decreased 5% (P < 0.001) and PTH increased 21% (P = 0.05) during TAM treatment. Total cholesterol decreased 15% (P < 0.001), and calculated low density lipoprotein cholesterol decreased 22% (P < 0.001); levels of triglycerides and high density lipoprotein did not change significantly. We conclude that short term TAM treatment inhibits bone turnover in women over 70 yr of age.