Metacarpal bone loss in middle-aged women: "horse racing" in a 9-year population based follow-up study.

Differences in the rate of metacarpal bone loss were evaluated in a 9 year population based follow-up study among 799 women initially aged 45-64 years, using initial and follow-up radiographs of the hands. Metacarpal bone loss started around the age of 50 years and was present in more than 95% of the women. The average annual rate of loss was approximately 1% of the initial value. The prevalence of osteopenia increased from 5% for women aged 45-49 years, up to 68% for women aged 70-76. The rate of bone loss was not similar for each individual. Regression analyses of rate of change-in-RCA on initial level of RCA indicated the presence of a consistent subgroup of fast bone losers. However, osteopenia at follow-up was more accurately predicted from initial bone density than from differences in the rate of loss.