NEFL and multiple sclerosis: While the association of NfL blood levels with age has been consistently demonstrated across a variety of patient populations and healthy controls (Khalil et al., 2018, 2020), their association with renal function and body mass index (BMI) was only recently reported in elderly diabetic patients and younger patients with multiple sclerosis, respectively (Korley et al., 2019; Akamine et al., 2020; Manouchehrinia et al., 2020).