Table 4: VLS participant characteristics.

Year of testing
MeasureBaselineYear 3 Year 6Year 9Year 12Year 15Year 18
( 𝑛 = 1 0 1 1 ) ( 𝑛 = 7 3 3 ) ( 𝑛 = 5 7 9 ) ( 𝑛 = 4 1 7 ) ( 𝑛 = 2 8 6 ) ( 𝑛 = 9 1 ) ( 𝑛 = 5 2 )

Retention from previous testing (%)a737972697257
Age [M (SD)]68.8 (6.8)71.4 (6.7)73.7 (6.5)76.6 (6.0)79.3 (5.2)82.2 (4.6)85.1 (3.6)
Years of education at baseline [M (SD)]14.9 (3.3)15.4 (3.2)15.7 (3.1)15.8 (3.1)15.8 (3.1)15.2 (3.1)14.8 (2.8)
Sex, female [ 𝑛 (%)]642 (63.5)459 (62.6)353 (61.0)256 (61.4)177 (61.9)60 (65.9)35 (67.3)
Reasoning [M (SD)]b11.1 (4.6)11.6 (4.2)10.3 (4.7)10.3 (4.6)9.9 (4.6)7.5 (4.7)6.5 (4.2)
Fluency [M (SD)]17.5 (4.4)17.9 (4.4)17.7 (4.4)17.2 (4.8)16.3 (4.9)14.7 (5.8)13.8 (5.4)
Memory [M (SD)]c13.7 (5.9)14.6 (6.0)14.7 (6.1)14.8 (6.4)11.8 (5.5)13.0 (6.3)
Semantic knowledge [M (SD)]43.6 (7.5)44.6 (6.3)44.3 (6.0)44.2 (5.9)43.6 (5.7)42.7 (7.1)42.6 (6.6)
Cognitive activity [M (SD)]
 Communication0.1 (0.8)0.1 (0.8)0.0 (0.8)−0.1 (0.8)−0.2 (0.8)−0.4 (0.8)−0.4 (0.7)
 Computation0.1 (0.8)0.0 (0.8)0.0 (0.8)0.0 (0.8)−0.1 (0.8)−0.3 (0.7)−0.5 (0.7)
 Conundrums0.0 (0.8)0.0 (0.8)0.0 (0.8)0.0 (0.8)0.0 (0.8)−0.2 (0.9)−0.2 (0.8)
Activity change [M (SD)]
 Communication0.0 (0.5)−0.2 (0.6)−0.3 (0.6)−0.4 (0.6)−0.5 (0.6)−0.6 (0.5)
 Computation−0.1 (0.6)−0.2 (0.6)−0.3 (0.6)−0.4 (0.7)−0.4 (0.7)−0.5 (0.8)
 Conundrums 0.0 (0.6)−0.1 (0.6)−0.1 (0.7)−0.2 (0.6)−0.3 (0.8)−0.4 (0.7)

M: mean; SD: standard deviation. The theoretical ranges for each measure with a defined upper limit are as follows: reasoning 0–20, memory 0–30, and semantic knowledge 0–54. The cognitive activity scores are on a normal metric with means of approximately 0 and SD of approximately 0.8.
aThe 1986 cohort was followed for up to 18 years and 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.