Table 2.
Description of available data on cognitive test scores for 3MS and DSST by visit in CHS participants.
| Milestone years | Visit | Caucasian cohort (N=3575) |
AA cohort (N=481) |
||||||
|---|---|---|---|---|---|---|---|---|---|
| 3MS |
DSST |
3MS |
DSST |
||||||
| Median (interquartile range) | N missing | Median (interquartile range) | N missing | Median (interquartile range) | N missing | Median (interquartile range) | N missing | ||
| 1988/89 | 1/2 | 92.05 (88.6,94.7) | 46 | 39 (30,47) | 39 | – | – | – | – |
| 3 | 93 (88,97) | 62 | 41 (32,50) | 129 | – | – | – | – | |
| 4 | 94 (89,97) | 130 | 41 (32,49) | 221 | – | – | – | – | |
| 1992/93 | 5 | 94 (89,97) | 325 | 40 (32,49) | 421 | 87 (79,92) | 1 | 31 (20,39) | 27 |
| 6 | 95 (90,98) | 591 | 41 (32,50) | 725 | 89 (81.5,94) | 34 | 31 (22,40) | 73 | |
| 7 | 94 (88,97) | 721 | 41 (32,50) | 890 | 89 (80,93) | 40 | 31 (22,41) | 83 | |
| 8 | 94 (88,97) | 986 | 41 (32,50) | 1145 | 88 (80,94) | 59 | 31 (21.5,40.5) | 102 | |
| 9 | 95 (90,98) | 1198 | 40 (30,48) | 1349 | 89 (82,95) | 84 | 30 (22.25,40) | 127 | |
| 10 | 95 (88,98) | 1394 | 40 (31,49) | 1551 | 89 (80,95) | 110 | 31 (23,41) | 153 | |
| 1998/99 | 11 | 95 (89,98) | 1548 | 40 (30,49) | 1683 | 89 (79,94) | 152 | 31 (22,40) | 184 |
This table displays medians for the population by visit, and thus does not preserve the pattern of change within individuals. Due to drop out of sicker participants, medians do not appear to decline over time. The mixed effects models in our analyses address this by preserving the correlation within individuals over time. On average, a participant from the Caucasian Cohort declines −1.22 point per year on the 3MS and −0.67 per year on the DSST. The average decline per year in the AA Cohort for the 3MS is −0.80 and −0.36 for the DSST.