We hypothesized that: 1) higher blood HbA1c and glucose levels as well as the presence ofT2D diagnosis would be associated with lower plasma Aβ42/40 ratio and higher plasma t-tau and neurofilament light (NfL) levels; and 2) the relationships of blood HbA1c and glucose levels as well as the presence of T2D diagnosis with AD plasma biomarkers would be stronger in Mexican Americans than non-Hispanic Whites. This evidence concerns the gene NEFL and type 2 diabetes mellitus.