Examining the Risk Factors Associated with Multiple Sclerosis


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