Levels of cerebrospinal fluid neurofilament light protein in healthy elderly vary as a function of TOMM40 variants

► Our sample is healthy, cognitively intact elderly from the community. ► We examined whether APOE and TOMM40 affected levels of CSF neurofilament light (NFL). ► CSF NFL was greater when APOE ε4 carriers did not also carry a short TOMM40 variant. ► CSF NFL levels were found to correlate with CSF cortisol levels.