NEFL and major depressive disorder: Particularly, older age, male sex, higher body mass index (BMI), higher number of previous relapses, exposure to higher latitudes, lower median income, higher depression scores, smoking status, higher baseline MRI T2 lesion load (T2L), cerebrospinal fluid (CSF) biomarkers, and neurofilament light chains (NFL), have been shown to predict the MS disease time-course to some degree18–25.