APOA1 and amyotrophic lateral sclerosis: Excluding those diagnosed within 5 years of their first visit, higher HDL (HR 0.66, 95% CI 0.49 to 0.88, p=0.005, adjusted p=0.020) or apoA1 (HR 0.77, 95% CI 0.61 to 0.98, p=0.034, adjusted p=0.110) levels were associated with a reduced risk of ALS.