Radiogrammetry at four bone sites in normal middle aged women. Their relation to each other, to calcium metabolism and to other biological variables

In 167 women, ages 41±3.5 years, who constituted 80 per cent of nuns of this age group in the Omaha area, body dimensions and radiogrammetric indices were determined in radius, femoral shaft and second metacarpal. Calcium, phosphorus and nitrogen balance were measured and calcium kinetics were calculated following oral and intravenous administration of two radioisotopes of calcium. The bone indices were significantly correlated to each other. The femoral diameter was correlated to all the kinetic variables, the radial to many, and the metacarpal to a few. All bone diameters were correlated to height, but only the femoral diameter to body weight. Femoral shaft diameter increased with time after the menopause, but was not correlated to age. There was no correlation between any bone variable and dietary calcium, absorbed calcium, or calcium balance. High dietary calcium was associated with lower bone resorption. There was no correlation between any bone variable and the urinary excretion of estrogens or 17 ketosteroids or 17 hydroxycorticosteroids. Although different bones of the skeleton are qualitatively and quantitatively related, in survey work the femoral shaft should be included as a skeletal marker in addition to the second metacarpal. Femoral expansion occurs in women after the menopause. In normal women, dietary calcium is unrelated to skeletal indices.