Amyotrophic lateral sclerosis: A higher than expected incidence in people over 80 years of age

Our objective was to determine the age-specific incidence and clinical-epidemiological characteristics of an amyotrophic lateral sclerosis (ALS) cohort of patients in Catalonia (Spain). New cases diagnosed between 1 January 2004 and 31 December 2013 were 41 (20 males and 21 females), with an annual crude incidence rate of 2.7 per 100,000 person-years (95% CI 1.90-3.59). The incidence rate increased with age reaching a peak in the age group of 70-79 years. There was a non-significant decrease in the incidence rate in the group of patients over 80 years (p-value = 0.75) at 17.99 per 100,000 person years (95% CI 7.81-28.17). The percentage of patients over 80 years of age was 29.3% and over age 85 years was 9.8%. The prevalence rate at the end of the study period was 8.38/100,000 of the total population. Mean age at symptom onset was 76.0 years. Onset of symptoms was bulbar or generalized in 36.6% of cases. In conclusion, ALS incidence in Osona is within the range of other countries across Europe. Our results suggest that the age-specific incidence rate of ALS increases with age through the oldest age groups suggesting an age-risk effect to develop the disease.