Individual characteristics including age, genetic profiles, obesity, and smoking status contribute to heterogeneity in multiple sclerosis (MS) presentation and modulate early disease course evolution, according to a recent study. Using a retrospective cross-sectional study of MS cases, researchers investigated: age of onset (AOO), number of impaired functional domains (NIFDs), time to second relapse (TT2R), and early relapse activity (ERA). Machine learning variable selection was applied to epidemiologic data for each outcome, followed by multivariable regression models. The models were further adjusted for HLA-DRB1*15:01 carrier status and a MS genetic risk score (GRS). The TT2R and ERA analyses were restricted to relapsing remitting MS cases. They found:

• HLA-DRB1*15:01, GRS, and smoking were associated with earlier AOO.
• Cases who were male, obese, had lower education, or had primary progressive MS were older at onset.
• Those with relapsing remitting MS and of lower socioeconomic status had increased NIFDs.
• Among relapsing remitting cases, those who were older at onset, obese, and had polyfocal presentation had shorter TT2R, while ERA was greater among those younger at onset and who were obese.