Associations of Abnormal Sleep Duration and Chronotype with Higher Risk of Incident Amyotrophic Lateral Sclerosis: A UK Biobank Prospective Cohort Study

<b>Background:</b> The occurrence of sleep disturbances in amyotrophic lateral sclerosis (ALS) patients is widely reported. However, there is still a lack of reliable evidence of a relationship between sleep disturbances and the risk of developing ALS. The aim of this study was to prospectively investigate the longitudinal associations between sleep traits and the risk of incident ALS. <b>Methods:</b> We included information from 409,045 individuals from the prospective cohort of the UK Biobank. Sleep traits at baseline were measured using a standardized questionnaire. All sleep traits were analyzed in relation to the subsequent incidence of ALS using Cox proportional hazards models. <b>Results:</b> Multivariate analysis showed that 6-7 h of sleep was related to the lowest risk for ALS. A long sleep duration (≥8 h) was associated with an increased risk of ALS incidence (HR: 1.31, 95% CI: 1.07-1.61; <i>p</i> = 0.009). A short sleep duration (<6 h) was associated with an increased risk of ALS incidence (HR: 1.91, 95% CI: 1.10-3.30, <i>p</i> = 0.021) in females. In participants aged ≥65 years, eveningness was associated with increased ALS risk (HR: 1.32, 95% CI: 1.08-1.61; <i>p</i> = 0.006). <b>Conclusion:</b> Our results hint at a sleep duration that is too short or too long, and certain chronotypes might be related to the risk of developing ALS. Despite the limitations imposed by the study design and the subjectivity of sleep information, our findings suggest that sleep disturbances may influence the risk of developing ALS.