Abstract
BACKGROUND AND PURPOSE: Earlier data suggest an association between amyotrophic lateral sclerosis (ALS) and autoimmune disease, but data on its association with celiac disease (CD) are limited. METHODS: The risk of ALS in 29 093 individuals with CD, according to small intestine biopsy (villous atrophy, Marsh 3) carried out at Sweden's 28 pathology departments in 1969-2008, was compared with that in 144 515 age- and sex-matched reference individuals from the general population. ALS was defined as a hospitalization or outpatient visit with ALS according to the Swedish Patient Register. We used Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for ALS. RESULTS: During follow-up 12 (3.7/100 000 person-years) individuals with CD and 56 (3.5/100 000 person-years) reference individuals had a diagnosis of ALS. This corresponded to an HR of 1.0 (95% CI 0.5-1.8). HRs were significantly higher in the first year of follow-up (4.1; 1.2-13.4) than 1-5 years after first CD diagnosis (0.8; 0.2-2.7) or after more than 5 years of follow-up (0.5; 0.2-1.5). Relative risk estimates were similar in men and women but were higher at the end of the study period [HR for ALS in patients diagnosed with CD in year 2000 or later was 2.1 (95% CI 0.9-4.8)]. CONCLUSIONS: This study found no association between CD and ALS. Earlier reports of a positive association may be due to surveillance bias just after CD diagnosis or expedited diagnostic work-up of ALS.