Current evidence suggests that MS may be largely preventable. Understanding the mechanism, timing, and impact of risk factors will aid the development of prevention strategies.4

Table 1: Types of MS


Clinical Disease Course

Relapsing/Remitting Multiple Sclerosis (RRMS)


  • Most common type (approximately 85% of cases)
  • Discrete attacks that evolve over days to weeks, followed by some partial to complete recovery over weeks to months.
  • No worsening neurological function between attacks
  • Can be a precursor of SPMS
  • Mean age of onset, 30 years old

Secondary Progressive Multiple Sclerosis (SPMS)

  • Initial relapses, followed by gradual, steady neurological deterioration
  • Not associated with acute attacks.

Primary Progressive Multiple Sclerosis (PPMS)


  • Less common (approximately 10% to 15% of the MS population)
  • Rapid disease progression
  • No relapsing patterns
  • Mean age of onset 40 years old
Progressive Relapsing Multiple Sclerosis (PRMS)  

  • Steady functional decline from disease onset
  • Later superimposed acute attacks.
  • Sometimes indistinguishable from PPMS during early stages until relapses occur

Loma and Hyman, 20111
Tremlett et al, 200920
Koch et al, 200921
Koch et al, 201022
Lublin et al, 201423