Yield point in prediction of compressive behavior of lumbar vertebral body by dual-energy x-ray absorptiometry.

The aims of the present study were to evaluate the influence of bone mineral content (BMC) and density on the behavior of the lumbar vertebra during compression and to determine critical points during compression. Dual-energy X-ray absorptiometry (DXA) and compression tests were performed on 44 vertebral bodies obtained from 22 cadavers. The results of the study indicate that bone mineral content measured by DXA were strongly correlated with ultimate failure load (r = 0.

Sunscreen and risk of osteoporosis in the elderly: a two-year follow-up.

Background: It has been suggested that the use of sunscreens to prevent skin cancer may put the population at risk of vitamin D deficiency, which in turn may lead to secondary hyperparathyroidism, loss of cortical bone and, ultimately, osteoporotic fractures.

Objective: To investigate whether sunscreen SPF15 may lead to loss of bone mass.

Methods: We followed 10 sunscreen users and 18 controls over 2 years, including two summers, two winters and a basal period (winter).