Degenerative changes at the lumbar spine—implications for bone mineral density measurement in elderly women

Summary Degenerative changes of the lumbar spine may lead to misinterpretation of bone mineral density (BMD) measurements and cause underdiagnosis of osteoporosis. This longitudinal study of 1,044 women, 75 years at inclusion and followed for 10 years, shows that identification of apparent degenerative changes on the dual energy X-ray absorptiometry (DXA) scan can increase the proportion diagnosed. Introduction In the elderly, degenerative manifestations in the lumbar spine may result in falsely elevated BMD values, consequently missing a large proportion of those with osteoporosis. Our aim was to determine the distribution and impact of degenerative changes on lumbar spine DXA over time and its clinical implications. Methods Participants were 1,044 women from the population-based Osteoporosis Risk Assessment cohort. All women were 75 years old at invitation and followed up after 5 years ( n = 715) and 10 years ( n = 382). Degenerative changes were evaluated visually on the DXA image for each vertebra L1 to L4 (intraobserver precision kappa values of 0.66–0.70). Results At baseline, apparent degenerative changes were more frequent in the inferior segments of the lumbar spine [5 % (L1), 15 % (L2), 26 % (L3), and 36 % (L4)] and increased over time. At 10 years, the prevalences were 20 % (L1), 39 % (L2), 59 % (L3), 72 % (L4), resulting in a significant increase in overall BMD. In women without apparent degenerative changes, BMD remained stable between 75 and 85 rather than an expected bone loss. At baseline, 37 % had osteoporosis (BMD