Association of fractures with the incidence of amyotrophic lateral sclerosis

Abstract

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
• fractures
• cohort study
• risk factors

Acknowledgements

This study was supported by Swedish Research Council (SIMSAM grant no. 80748301 and grant no. 2015-03170), the Swedish Research Council for Health, Working life, and Welfare (grant no. 2011-0172), the Karolinska Institutet, the Swedish Society of Medical Research, the National Institutes of Health/Karolinska Institutet graduate partnership programme, the Intramural Research Program of National Institutes of Health, National Institute of Environmental Health Sciences (Z01-ES-049005), and the EU Joint Programme - Neurodegenerative Disease Research (JPND) project (www.jpnd.eu).

Declaration of interest

The authors declare that they have no conflict of interest.

Supplementary material available online