Influence of the Sagittal Vertical Axis on the Risk of Falls in Community-Dwelling Elderly People: A Retrospective Longitudinal Study

INTRODUCTION: Falling is an age-related problem that increases with age. Compared with younger people, elderly people possess increased risk factors for falls, and falling among the elderly is associated with increased mortality. Risk factors for falls have been reported in elderly outpatients; however, whether sagittal spinal posture affect the risk of falls in community residents remains unclear. Therefore, we aimed to investigate the influence of sagittal spinal posture on the risk of falls in elderly community-dwelling people using spino-plevic sagittal parameters in a retrospective longitudinal study. METHODS: A total of 463 volunteers (96 men and 367 women; mean age, 72.8 years) who underwent a routine physical checkup were evaluated. Baseline whole spine and lower limb radiography, physical tests, bone mineral density (BMD), number of medications and comorbidities, patient-reported outcomes (PROs), and a history of falls in the previous four years period were examined. RESULTS: Univariate analysis revealed older age, lower height and weight, higher prevalence of vertebral fractures, higher number of medications, poor physical test scores including one-leg standing test and prone trunk extension, poor PROs, a higher sagittal vertical axis, and higher pelvic tilt (PT) as factors significantly associated with the risk of falls, and multivariate analysis revealed a higher sagittal vertical axis [odds ratio (OR), 1.08; 95% confidence interval (CI), 1.002-1.013; P = 0.02] and locomotive syndrome assessed using the 25-Question Geriatric Locomotive Function Scale score (OR, 1.028; 95% CI, 1.004-1.053; P = 0.03) to be associated with the risk of falls, independent of other factors in the univariate analysis. CONCLUSIONS: The sagittal vertical axis was an independent risk factor for falls, and the prevalence of vertebral fractures and prone truck extension correlated with the sagittal vertical axis. Prospective and intervention studies are needed to prevent future falls in elderly community volunteers with a higher sagittal vertical axis.