IMPACT OF SPINAL DEGENERATIVE CHANGES ON THE EVALUATION OF BONE-MINERAL DENSITY WITH DUAL-ENERGY X-RAY ABSORPTIOMETRY (DXA)

The purpose of this study is to evaluate degenerative factors in a pos tmenopausal patient group and differentiate the influence on bone mine ral density (BMD) measurements by dual-energy X-ray absorptiometry (DX A). The patients and methods included an investigation of 144 postmeno pausal women (mean 63.3 years) with PA-DXA of the spine. Degenerative factors (osteophytes, osteochondrosis, scoliosis, and vascular calcifi cation) were evaluated from plain lumbar radiographs, their estimated probability was analyzed as a function of age, and their influence on BMD measured by PA-DXA was determined. The results of the study reveal ed osteophytes in 45.8%, vascular calcifications in 24.3%, scoliosis i n 22.2%, osteochondrosis in 21.5%. The estimated probability for degen erative factors increased from 35 to 80% in the 55- to 70-year age gro up. Osteophytes and osteochondrosis were associated with up to a 14% i ncrease in BMD values (P < 0.001). Vascular calcifications showed a po sitive trend, whereas scoliosis did not show a discernible influence. We concluded that degenerative factors, except for scoliosis, showed a n influence on BMD as measured by DXA. Their prevalence increased rapi dly between 55 and 70 years of age. Interpretation of PA-DXA spine dat a for subjects of or above this age range should be complemented by pl ain film radiographs.