Age of Symptom Onset in Multiple Sclerosis
Multiple sclerosis typically presents in young adults between the ages of 20 and 30 years. 1
Primary Age of Onset
- MS most commonly affects individuals between 18 and 50 years of age, with the mean age of onset being 20-30 years 1
- The 2017 McDonald Criteria for MS diagnosis applies best to individuals between 10 and 59 years of age 2
- MS diagnosis requires evidence of central nervous system lesions disseminated in both time and space, as determined through clinical presentation and MRI findings 2
Age Distribution Patterns
- MS affects women more frequently than men, with a female to male ratio of nearly 3:1 1
- The prevalence of MS worldwide ranges from 5 to 300 per 100,000 people and increases at higher latitudes 1
- Only about 5% of MS cases are diagnosed after age 50, which is defined as late-onset MS (LOMS) 3
Late-Onset MS Characteristics
- When MS onset occurs at age 50 or older, it is defined as late-onset MS (LOMS) 4
- LOMS presents with different clinical characteristics compared to typical MS:
- More likely to have a progressive disease course rather than relapsing-remitting 3
- Motor symptoms are the most common presentation at onset (63.3%) 5
- More rapid progression to disability with a higher Progression Index 5
- Greater delay in diagnosis due to overlapping symptoms with other age-related conditions 4
Pediatric MS Considerations
- MS can also occur in children and adolescents under age 18, though this is less common 4
- In pediatric cases (under age 11), special diagnostic care is needed 6
- The presence of at least one black hole (hypointense lesion on T1-weighted MRI) and at least one periventricular lesion at baseline helps distinguish children with MS from those with monophasic demyelination 6
Diagnostic Challenges by Age
- In patients older than 50 years or with vascular risk factors, more stringent diagnostic criteria should be applied (e.g., a higher number of periventricular lesions) 6
- Misdiagnosis and a remarkable gap in diagnosis of LOMS is a challenge in the elderly population 3
- Depression may be an early presentation of LOMS, with 20% of patients experiencing major depressive episodes in the two years prior to MS diagnosis 5
Impact on Life Expectancy and Quality of Life
- Overall life expectancy for MS patients is reduced compared to the general population (75.9 vs 83.4 years) 1
- With disease-modifying therapies, life span has increased substantially over the past two decades 7
- Approximately 90% of people diagnosed with MS in their 20s may now live into their 70s 7
- Currently, about 25% of people with MS are mature adults over 65 years old 7
Understanding the typical age of onset and age-related variations in MS presentation is crucial for accurate diagnosis and appropriate management of this complex neurological condition.