Late-Onset Multiple Sclerosis: Epidemiology and Clinical Characteristics

Late-Onset Multiple Sclerosis (LOMS) is conventionally defined by symptom onset at age 50 years or older, representing 4–12 per cent of all MS cases worldwide. Epidemiological studies indicate a modest female predominance that is less marked than in younger-onset cohorts, and geographic variations reflect environmental and genetic factors. Clinically, LOMS patients more often present with a primary progressive course, higher baseline disability scores and a lower relapse frequency in the early disease phase, yet reach irreversible disability milestones more rapidly. Common initial manifestations include motor deficits, spinal cord syndromes and, less frequently, sensory or cerebellar symptoms. Ageing of the immune system—immunosenescence—coupled with cumulative comorbidities influences both pathophysiology and therapeutic decision-making, as standard disease-modifying therapies may be less well tolerated or efficacious. Neuroimaging studies reveal an intensified interaction between age-related brain changes—such as reduced plasticity, iron accumulation and enlarged perivascular spaces—and demyelinating lesions, underscoring the need for tailored diagnostic criteria and vigilant monitoring. With an ageing global population, recognition of LOMS as a distinct clinical entity is critical to optimise management strategies and improve long-term outcomes.

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Late-Onset Multiple Sclerosis: Epidemiology and Clinical Characteristics publication trend

The graph below shows the total number of articles in late-onset multiple sclerosis: epidemiology and clinical characteristics across all publications each year (not limited to Nature Index journals).

Technical terms

Late-Onset Multiple Sclerosis (LOMS): Onset of MS symptoms at age 50 years or older, associated with distinct demographic and clinical profiles.

Expanded Disability Status Scale (EDSS): A method of quantifying neurological impairment and disability in MS on a scale from 0 (normal) to 10 (death due to MS).

Disease-Modifying Therapy (DMT): Treatments aimed at reducing relapse rate, delaying progression and limiting new lesion formation in MS.

Immunosenescence: Age-related decline and dysregulation of the immune system, affecting disease course and treatment response.

Relapsing-Remitting MS (RRMS): MS subtype characterised by clearly defined exacerbations (relapses) followed by periods of partial or complete recovery.

Primary Progressive MS (PPMS): MS subtype marked by continuous neurological decline from disease onset without distinct relapses or remissions.

References

1. The ageing central nervous system in multiple sclerosis: the imaging perspective. Brain (2024).
2. Clinical Characteristics and Long-Term Outcomes of Late-Onset Multiple Sclerosis. Neurology (2024).
3. Late-Onset MS: Disease Course and Safety-Efficacy of DMTS. Frontiers in Neurology (2022).
4. Aging in multiple sclerosis: from childhood to old age, etiopathogenesis, and unmet needs: a narrative review. Frontiers in Neurology (2023).
5. Clinical and Epidemiological Aspects of Late Onset Multiple Sclerosis in East-Azerbaijan, Iran; A Population-Based Study. Archives of Iranian Medicine (2022).