Table 1

Characteristics of the sample at study entry

CharacteristicParticipants with missing dataTotal analysed sampleAnalysed participants
NCI at baselineMCI at baseline
N (%)4035 (22)14 490 (78)9773 (67)4717 (33)
Age, years, mean (SD)73.0 (8.9)72.2 (8.9)71.7 (9.0)73.3 (8.6)
Sex, N (%)
 Men1550 (38)5865 (40)3407 (35)2458 (52)
 Women2485 (62)8625 (60)6366 (65)2259 (48)
Race, N (%)
 White2982 (74)11 806 (81)7914 (81)3892 (83)
 Black680 (17)1776 (12)1269 (13)507 (11)
 Asian137 (3)343 (2)209 (2)134 (3)
 Multiracial/other236 (6)565 (4)381 (4)184 (4)
Education, years, mean (SD)15.6 (3.2)15.7 (3.1)15.9 (2.9)15.4 (3.3)
Follow-up data, years, mean (SD)3.0 (2.9)5.3 (3.5)5.8 (3.6)4.4 (3.0)
MMSE score, mean (SD)28.0 (2.2)28.4 (2.0)28.9 (1.4)27.1 (2.5)
Frailty index score
 Median (IQR)0.11 (0.07–0.16)0.09 (0.05–0.14)0.08 (0.04–0.11)0.13 (0.09–0.20)
 Range0.00–0.530.00–0.560.00–0.510.00–0.56
APOE ε4 status, N (%)
 ε4 non-carrier513 (70)9459 (65)6801 (70)2658 (56)
 ε4 carrier221 (30)5031 (35)2972 (30)2059 (44)
  • As participants were excluded due to missing covariate data (age, sex, education and APOE ε4 status), the values presented here represent the mean values for participants in which data on those variables were available. Ninety-three missing race values were recoded to ‘Multiracial/other’ for descriptive purposes. Some proportions may not sum to 100% due to rounding.

  • MCI, mild cognitive impairment; MMSE, Mini-Mental State Examination; NCI, not cognitively impaired.