Lumbar Scoliosis in Postmenopausal Women Increases with Age but is not Associated with Osteoporosis

CONTEXT: The contribution of lumbar scoliosis to osteoporosis is unknown. OBJECTIVE: This work aimed to determine the prevalence and relationship of lumbar scoliosis to osteoporosis in aging women. METHODS: A cross-sectional analysis used dual-energy x-ray absorptiometry (DXA) scans of randomly selected groups of postmenopausal women (64-68, 74-78, and 84-88 years; N = 300 each) in a university teaching hospital from 2014 to 2019. Lumbar Cobb angle was tested for an association to femoral neck (FN), total hip (TH), and spine T score, age, weight, and ethnicity. Logistic regression tested an association between scoliosis (Cobb angle > 10°) and osteoporosis (T score ≤ –2.5). Available sequential DXA scans (N = 51) were analyzed for changes in Cobb angle using a linear mixed model of these longitudinal data. RESULTS: Osteoporosis and Cobb angle both increased with age: from 22% and 4.4 (SD = 7.8) respectively in 64- to 68-year-olds to 32.9% and to 9.7 (SD = 9.2) in women age 84 to 88 years. The prevalence of clinically significant scoliosis rose from 11.5% in the youngest group, to 27.3% and 39.4% in the age 74 to 78 and 84 to 88 cohorts, respectively. Cobb angle increased 0.7° per year of follow-up. After adjusting for covariates, there was no significant association between T scores at any site (TH, FN, or spine) and Cobb angle. CONCLUSION: Based on screening DXAs, the incidence and degree of lumbar scoliosis increases significantly in women between age 65 and 85 years. There was no association between the incidence of lumbar scoliosis and FN bone density.