Objective: Elevated bone turnover observed in ALS patients suggests poor bone health and increased fracture risk. We therefore evaluated the relationship of fracture to subsequent ALS risk.
Methods: We followed 4,529,460 Swedes from 1987 to 2010 and identified ALS and fractures from the Swedish National Patient Register. We examined associations of ALS risk with all fractures, osteoporotic and non-osteoporotic fractures, and traumatic and non-traumatic fractures among individuals aged 30-80 years. We used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). We analysed the association of ALS with time since fracture using a Poisson regression model.
Results: All fractures (HR: 1.51, 95% CI 1.39-1.65) as well as osteoporotic (HR: 1.59, 95% CI 1.41-1.79), non-osteoporotic (HR: 1.46, 95% CI 1.31-1.63), traumatic (HR: 1.50, 95% CI 1.37-1.63), and non-traumatic (HR: 1.80, 95% CI 1.35-2.40) fractures were associated with a higher incidence of ALS. Increased ALS incidence was associated with fractures occurring from one (HR: 2.33, 95% CI 2.04-2.66) to 18 (HR: 1.19, 95% CI 1.01-1.43) years before ALS diagnosis.
Conclusions: Poor bone health may be related to ALS. These findings may offer insight into ALS pathophysiology.
Keywords: Amyotrophic lateral sclerosis; cohort study; fractures; risk factors.