GDF15 and Cognitive impairment: In addition to demonstrating that widely recognized ADRD biomarkers, such as CHI3L1 (YKL-40) [42], NfL [43], and GDF15 [44] are similarly associated with future cognitive impairment among APOEε4 carriers and APOEε3 homozygotes, we identified a set of 8 proteins to be uniquely predictive of future cognitive impairment among APOEε4 carriers.