White matter hyperintensity, neurofilament light chain, and cognitive decline

We aimed to determine whether combining white matter hyperintensity (WMH) with neurofilament light chain (NfL) could provide additional information for cognition in older adults.

Utilizing data from the population-based Chicago Health and Aging Project, we studied 701 individuals with both biomarkers and cognitive data during the follow-up period. NfL was measured using an ultrasensitive immunoassay, single-molecule array technology. MRI scans of the brain were acquired using 1.5-T systems. Global cognitive function was created as a composite measure of four neuropsychological tests, standardized and averaged to z-scores. Multivariable linear mixed-effects models were used to evaluate the association of WMH and NfL with the rate of cognitive decline.

Higher WMH and NfL were associated with a faster rate of cognitive decline during the follow-up; $$ -coefficients (95%CIs) were -0.011 (-0.02, -0.001) and -0.010 (-0.017, -0.003), respectively. In individuals with lower concentration of NfL (i.e., bottom tertile), a higher WMH volume was associated with a faster cognitive decline ( $$ : -0.030; 95%CI -0.046, -0.014). Similarly, in individuals with lower volumes of WMH (i.e., bottom tertile), a higher concentrations of NfL was associated with a faster cognitive decline ( $$ : -0.023; 95%CI -0.042, -0.005). When we combined WMH with NfL, we noted a graded association with increasing volumes of WMH, particularly in people with lower NfL values.

While both biomarkers, WMH and NfL, were similarly associated with the annual rate of cognitive decline, our study suggests that they provide different underlying mechanisms affecting cognition.