Table 4: VLS participant characteristics.

Year of testing
MeasureBaseline
( 𝑛 = 9 7 7 )
Year 3
( 𝑛 = 7 2 3 )
Year 6
( 𝑛 = 5 7 1 )
Year 9
( 𝑛 = 4 1 1 )
Year 12
( 𝑛 = 2 7 5 )
Year 15
( 𝑛 = 9 1 )
Year 18
( 𝑛 = 5 2 )
M (SD)M (SD)M (SD)M (SD)M (SD)M (SD)M (SD)

Retention from previous testing (%)a747972677957
Age 68.6 (6.7)71.3 (6.6)73.7 (6.4)76.5 (5.9)79.3 (5.2)82.2 (4.6)85.1 (3.6)
Years of education at baseline 14.9 (3.3)15.4 (3.2)15.6 (3.1)15.9 (3.1)15.8 (3.1)15.2 (3.1)14.8 (2.8)
Sex, female [ 𝑛 (%)]614 (62.8)450 (62.2)346 (60.6)251 (61.1)170 (61.8)60 (65.9)35 (67.3)
Reasoningb11.2 (4.7)11.7 (4.2)10.3 (4.7)10.3 (4.6)9.9 (4.6)7.5 (4.7)6.5 (4.2)
Fluency 17.7 (4.3)17.9 (4.4)17.7 (4.5)17.2 (4.8)16.3 (4.9)14.7 (5.8)13.8 (5.4)
Memoryc13.7 (5.9)14.7 (6.0)14.7 (6.1)14.9 (6.4)11.7 (5.4)13.0 (6.3)
Semantic knowledge 43.7 (7.4)44.7 (6.2)44.3 (6.0)44.2 (5.8)43.5 (5.7)42.7 (7.1)42.6 (6.6)
Social activity 23.0 (6.9)23.2 (7.2)22.8 (7.3)22.5 (7.2)21.2 (7.1)22.8 (7.7)21.1 (7.2)
Social activity change −0.1 (5.4)−0.3 (6.0)−0.9 (6.4)−2.5 (6.9)−3.5 (7.5)−5.3 (8.1)

M: mean, SD: standard deviation. The range for each measure with a defined upper limit is as follows: reasoning = 0–20, Memory = 0−30, and Semantic knowledge 0−54.
aThe 1986 cohort was followed for up to 18 years, the 1993 cohort for up to 12.
bThe reasoning measure was not given until year 6 for the 1986 cohort.
cThe memory measure was not given in year 18.