A study on the phalanx bone mineral content in 273 normal pre- and post-menopausal females (transverse study of age-dependent bone loss).

Quantitative Röntgen microdensitometry (QMD) can be used to provide a precise quantification of mean specific bone mass (rho) from standardized radiographs. The method is simple, non-invasive, low in cost and suitable for frequent repetition. Bone mineral mass at the mid-length (largely cortical bone) of the middle phalanx of digital II of the left and right hands was investigated. Normalized quantification of bone structure can be achieved with a precision (coefficient of variation) of the order of 1%. Rho values were determined for the right and left phalanx in 273 apparently healthy women 43-73 years of age (mean menopausal age, 49.8 years) in an attempt to differentiate between normal changes with age and excessive bone mineral loss. The mean rate of age-dependent bone mineral loss was -1.4% per year in pre-menopausal women; in post-menopausal women between 50 and 57 years it was -3.5% per year and between 58 and 73 years it was -0.8% per year. The mean rate of change of bone mineral mass in the same group, as a function of the number of years after menopause, was -1.9% per year for the group 2-8 years after menopause and +0.1% per year for the group 9-20 years after menopause.