In cross-sectional analyses assessing GPL-FA in buccal cells at follow-up (B-1y), a significant inverse association with AD was observed for C18:2n-6 (OR = 0.567 [95% CI = 0.397;0.800], p = 0.0015); and a positive association was observed with C18:1n-9 (3.539 [2.193;5.988], p < 0.001), C20:4n-6 (2.021 [1.358;3.072], p < 0.001), C22:6n-3 (2.032 [1.338;3.131], p < 0.001), and ARA/LA (1.832 [1.351;2.595], p < 0.001). This evidence concerns the gene IL31RA and Alzheimer disease.