Copper supplementation and the maintenance of bone mineral density in middle-aged women

Abstract

Osteoporosis is a common disease of older women in developed countries. Hormone replacement therapy (HRT) is currently the most effective way of reducing the rate of bone loss in older women. This study investigated the effects of copper supplementation over 2 years on vertebral trabecular bone mineral density (VTBMD) of a group of 73 apparently healthy women, aged 45-56 years, recruited from a general practice in north Belfast. Women were given, at random and double blind, either a supplement of 3 mg copper as amino acid chelate or a placebo to take daily. At the beginning and end of the study, VTBMD of the lumbar vertebrae (L2-4) was measured by computed tomography-scan (CT-scan) and random blood samples were taken for putative measures of copper status (erythrocyte Cu and superoxide dismutase activity). The women were seen every 3 months to monitor compliance with supplementation. There was no difference in initial and final VTBMD for the 24 women who took the copper supplement (initial VTBMD 124.6 (32.1) mg/cm(3) and final VTBMD 123.8 (36.3) mg/cm(3)) while the 32 women who took the placebo had significantly lower VTBMD at the end of the study period (initial VTBMD 120.7 (29.2) mg/cm(3) and final VTBMD 113.2 (26.6) mg/cm(3), paired t-test P = 0.01). Seventeen women (14 allocated the copper supplement and three the placebo) stopped taking the supplement during the study. Although copper supplementation had no effect on the putative biochemical measurements of copper status, it appeared to have reduced the loss of VTBMD in these middle-aged women over a 2 year period. (C) 1997 Wiley-Liss, Inc.