Age of Onset for Amyotrophic Lateral Sclerosis (ALS)
The most common age of onset for ALS is approximately 58-60 years, with peak incidence occurring in the sixth decade of life. 1, 2
Typical Age Distribution
- The mean age of onset for sporadic ALS is approximately 60 years, though more recent data suggests the average is currently 58-60 years 1, 2
- The age group with the highest prevalence is 60-69 years 3
- There is a slight male predominance overall (M:F ratio approximately 1.5:1) 1, 4
Age Range Considerations
- While the peak is in the sixth decade, ALS can affect a wide age range 1
- The lowest number of ALS cases occurs in younger adults aged 18-39 years and in those over 80 years 3
- Only 9% of patients are younger than 50 years at diagnosis 5
- Between 40-51% of patients are older than 70 years at diagnosis 5
Important Clinical Caveat: Underrecognition in Elderly Patients
ALS is significantly underdiagnosed in elderly patients, with late-onset disease being more common than traditionally recognized. 5
- In one study, the median age at onset was 71.5 years (range 36-87 years), with 51% of patients older than 70 years at diagnosis 5
- Only 46% of elderly patients sent to neurology departments with ALS symptoms had ALS considered by the referring physician 5
- Elderly patients often present with atypical symptoms such as dysphagia, frailty, or general weakness that may be attributed to other age-related conditions 5
- Recent investigations show an increasing incidence in older persons, suggesting that the traditional teaching of mean onset at 60 years may underestimate late-onset disease 5
Epidemiologic Context
- The annual incidence of ALS is 1-2.6 cases per 100,000 persons 2
- Between October 2010 and December 2011, there were 12,187 prevalent cases of definite ALS in the United States, with a prevalence of 3.9 cases per 100,000 persons 3
- The majority of cases (85-90%) are sporadic, while 5-10% are familial 6, 1