Factors influencing lumbar spine bone mineral density assessment by dual-energy X-ray absorptiometry: comparison with lumbar spinal radiogram.

A study was conducted to determine the effect of radiographic findings of lumbar spinal changes upon bone mineral density measurements obtained by dual energy X-ray absorptiometry (DXA). Four hundred subjects were chosen from among 1543 community residents, aged 40-79 years. Study groups of 50 subjects each were selected by sex and 10-year age groups. This study investigated 390 of the 400 subjects who agreed to the conduct of spine bone mineral density measurement and spinal radiography. Lumbar spine radiograms were examined for findings of osteophyte formation, facet joint osteoarthritis, vertebral fracture, and aortic calcification. The prevalence of osteophyte formation, facet joint osteoarthritis, vertebral fracture, and aortic calcification increased with age in both men and women. On multiple regression analysis, bone mineral density was significantly higher (P < 0.001) in subjects with osteophyte formation or facet joint osteoarthritis than in those without these conditions, while bone mineral density was significantly lower in subjects with vertebral fracture. This study demonstrated that osteophyte formation, facet joint osteoarthritis, and vertebral fracture should be taken into account in the evaluation of bone mineral density by DXA in people in older age groups, since these conditions occur at a considerable rate in such subjects.