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).

Clinically prescribed sunscreen (sun protection factor 15) does not decrease serum vitamin D concentration sufficiently either to induce changes in parathyroid function or in metabolic markers.

Some studies have suggested that the use of sunscreens to prevent skin cancer may put the population at risk of vitamin D deficiency. We followed 24 sunscreen users and 19 controls over 2 years, including two summers, two winters and a basal period (winter). Vitamin D, parathormone and bone biological markers were evaluated each season.

Sodium fluoride treatment is a major protector against vertebral and nonvertebral fractures when compared with other common treatments of osteoporosis: a longitudinal, observational study.

In a 5-year observational study we have compared sodium fluoride (NaF) with different treatments commonly used in the treatment of osteoporosis: calcium, estrogens, androgens, and calcitonin, referred to as non-NaF. We have looked at the incidence of vertebral and nonvertebral fractures. At baseline, the NaF group, consisting of 125 patients (89% females) aged 65 +/- 10 (X +/- SE) had more crush fractures (P < 0.