[Density and bone mineral content and their relation to anthropometric parameters in a normal Chilean population. A...

We studied 227 normal women from 20 to 89 years of age. Bone density and mineral content was measured in vertebral bodies L2 to L4, both femurs and whole body, using a double beam photon densitometer with a 153Gd source. Body height remained between 156 and 158 cm up to age 64, then decreased gradually to 152 cm. Weight increased from age 35 to 69 (mean 9 kg) and then decreased. Mean bone density of the lumbar spine was 1.07 g/cm3 up to age 50. A marked decrease in density was observed for 10 years after that age, gradually slowing in later years. Mean density of the femoral neck was 0.931 g/cm3 up to age 50. A steady decline is observed in later ages down to 0.763. The density ratio of spine to femoral neck remains under 1.2 up to age 60, then increases progressively. Total mineral content, absolute or relative to body weight, was a less sensitive index. Total content decreased from above 2000 gm to about 1550 gm after age 70. The greater proportion of mineral contents is found in the lower extremities (30%). With increasing age a greater mineral loss was observed in the trunk, including spine and hips, compared to other segments. Our findings reveal bone densities somewhat lower than those reported from USA and higher than those reported from Denmark.