Table 3: SLS participant characteristics.

Year of testing
MeasureBaselineYear 7Year 14Year 21
( 𝑛 = 1 6 4 9 )( 𝑛 = 9 3 9 )( 𝑛 = 4 4 5 )( 𝑛 = 1 7 8 )

Retention from previous testing (%)56.447.740.8
Age [M (SD)]67.1 (8.2)72.9 (7.3)77.9 (6.4)81.8 (4.9)
Education [M (SD)]14.6 (2.9)14.7 (2.8)14.8 (2.7)14.8 (2.8)
Sex, female [ 𝑛 (%)]859 (52)502 (54)255 (57)108 (60)
Reasoning [M (SD)]15.6 (5.8)15.2 (5.6)14.3 (5.5)14.0 (5.3)
Fluency [M (SD)]38.6 (12.8)37.5 (13.1)36.7 (12.7)38.8 (14.5)
Memory [M (SD)]12.5 (4.0)12.0 (4.1)11.5 (4.2)11.6 (4.0)
Semantic knowledge [M (SD)]25.0 (6.7)25.3 (6.6)25.8 (6.2)25.8 (5.9)
Cognitive activity [M (SD)]2.4 (1.2)2.5 (1.2)2.5 (1.2)2.3 (1.2)
Activity change [M (SD)]−0.1 (1.1)−0.2 (1.1)−0.5 (1.3)

M: mean; SD: standard deviation. The theoretical ranges for each measure with a defined upper limit are as follows: education = 0–20, reasoning = 0–30, memory = 0–20, semantic knowledge = 0–36, and cognitive activity = 0–5.