Table 4.
VLS participant characteristics.
| Year of testing | |||||||
|---|---|---|---|---|---|---|---|
| Measure | Baseline (n = 977) |
Year 3 (n = 723) |
Year 6 (n = 571) |
Year 9 (n = 411) |
Year 12 (n = 275) |
Year 15 (n = 91) |
Year 18 (n = 52) |
| M (SD) | M (SD) | M (SD) | M (SD) | M (SD) | M (SD) | M (SD) | |
| Retention from previous testing (%)a | — | 74 | 79 | 72 | 67 | 79 | 57 |
| 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) |
| Reasoningb | 11.2 (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) |
| Memoryc | 13.7 (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.