Cerebrovascular injury as a risk factor for amyotrophic lateral sclerosis

OBJECTIVE: To use an unbiased method to test a previously reported association between cerebral arteriovenous malformation (AVM) embolisation and the subsequent development of amyotrophic lateral sclerosis (ALS). METHODS: A hospital record linkage database was used to create cohorts of individuals coded as having cerebral and peripheral vessel AVMs, stroke (separately for haemorrhagic and ischaemic), transient ischaemic attack (TIA) and subarachnoid haemorrhage (SAH). The rate ratio for subsequent ALS was compared to a reference cohort. RESULTS: An increased rate ratio for ALS was found in relation to prior AVM (2.69; p=0.005), all strokes (1.38; p<0.001), and TIA (1.47; p<0.001). CONCLUSIONS: Cerebrovascular injury from a variety of causes, rather than the presence of AVM or the associated embolisation procedure per se, may be a risk factor for ALS within the context of a more complex multiple-hit model of pathogenesis.