Table 1.

Baseline characteristics of the ACT and HRS samples

Characteristics	ACT (N = 2330)	HRS (N = 5964)
Age, mean (SD)	75.1 (6.56)	74.8 (7.0)
Male, N (%)	1035 (44.4)	2616 (43.9)
GRS, mean (SD)	0.0 (1.0)	0.0 (1.0)
APOE ε4, N (%)	599 (25.7)	1534 (25.7)
CASI score at baseline visit, mean (SD)	0.32 (0.71)
Memory score at baseline visit, mean (SD)		0.89 (0.47)

Abbreviations: ACT, Adult Changes in Thought; CASI, Cognitive Abilities Screening Instrument; GRS, genetic risk score; HRS, Health and Retirement Study; SD, standard deviation.