Table 1.
Demographic characteristics
| Characteristic | Overall | White | African-American | Hispanic | ||||
|---|---|---|---|---|---|---|---|---|
| Cohort | 1905–1920 | 1921–1935 | 1905–1920 | 1921–1935 | 1905–1920 | 1921–1935 | 1905–1920 | 1921–1935 |
| N | 1034 | 1806 | 254 | 514 | 383 | 573 | 397 | 719 |
| Birth year (m, SD) | 1916 (3.4) | 1926 (3.9)* | 1916 (3.3) | 1926 (3.8)* | 1916 (3.4) | 1926 (3.9)* | 1916 (3.3) | 1926 (3.9)* |
| Baseline age (years; m, SD) | 79.6 (3.9) | 72.5 (3.7)* | 80.5 (3.6) | 72.7 (3.7)* | 79.4 (4.0) | 72.7 (3.8)* | 79.2 (3.9) | 72.3 (3.7)* |
| Number of visits (m, SD) | 3.2 (1.8) | 3.2 (1.8) | 3.0 (1.7) | 3.4 (1.8)* | 3.1 (1.7) | 3.2 (1.7) | 3.3 (1.8) | 3.2 (1.9) |
| Time between visits (m, SD) | 2.5 (1.0) | 3.2 (1.2)* | 2.6 (1.3) | 3.2 (1.1)* | 2.4 (0.8) | 3.0 (1.1)* | 2.5 (0.9) | 3.2 (1.4)* |
| Sex (n, % female) | 719, 69.5 | 1161, 64.3* | 166, 65.4 | 302, 58.8 | 282, 73.6 | 379, 66.1* | 271, 68.3 | 480, 66.8 |
| Baseline memory complaints (m, SD) | 1.6 (1.6) | 1.3 (1.6)* | 1.3 (1.4) | 1.2 (1.4) | 1.6 (1.6) | 1.2 (1.5)* | 1.8 (1.7) | 1.5 (1.7)* |
| Education (m, SD) | 9.1 (4.7) | 10.3 (4.9)* | 12.4 (3.8) | 13.7 (3.5)* | 10.1 (3.6) | 11.7 (3.6)* | 6.1 (4.3) | 6.8 (4.3)* |
| CVD burden (m, SD) | 1.5 (1.0) | 1.6 (1.0) | 1.4 (1.1) | 1.5 (1.0) | 1.5 (1.0) | 1.7 (1.0)* | 1.6 (1.0) | 1.6 (1.1) |
| Diabetes Mellitus (n, % yes) | 229, 22.1 | 479, 26.5* | 37, 14.6 | 92, 17.9 | 84, 21.9 | 165, 28.8* | 108, 27.2 | 222, 30.9 |
| n, %missing | 55, 5.3 | 63, 3.5 | 16, 6.3 | 18, 3.5 | 16, 4.2 | 14, 2.4 | 23, 5.8 | 31, 4.3 |
| Heart Disease (n, % yes) | 367, 35.5 | 675, 37.4 | 96, 37.8 | 222, 43.2 | 130, 33.9 | 218, 38.0 | 141, 35.5 | 235, 32.7 |
| n, %missing | 55, 5.3 | 62, 3.4 | 16, 6.3 | 17, 3.3 | 16, 4.2 | 14, 2.4 | 23, 5.8 | 31, 4.3 |
| Stroke (n, % yes) | 168, 16.2 | 266, 14.7* | 35, 13.8 | 65, 12.6 | 60, 15.7 | 88, 15.4 | 73, 18.4 | 113, 15.7* |
| n, %missing | 210, 20.3 | 162, 9.0 | 46, 18.1 | 40, 7.8 | 83, 21.7 | 45, 7.9 | 81, 20.4 | 77, 10.7 |
| Hypertension (n, % yes) | 735, 71.1 | 76.6* | 169, 66.5 | 365, 71.0 | 277, 72.3 | 462, 80.6* | 289, 72.8 | 557, 77.5 |
| n, %missing | 60, 5.8 | 62, 3.4 | 17, 6.7 | 17, 3.3 | 17, 4.4 | 14, 2.4 | 26, 6.5 | 31, 4.3 |
| CSES (m, SD) | −.10 (.64) | .00 (.68)* | .16 (.61) | .36 (.64)* | −.07 (.51) | .05 (.56)* | −.29 (.70) | −.31 (.65) |
| Father’s education n, %no formal education | 84, 8.1 | 136, 7.5 | 10, 3.9 | 11, 2.1 | 12, 3.1 | 18, 3.1 | 62, 15.6 | 107, 14.9 |
| n, %grades 1–8 | 134, 13.0 | 313, 17.3 | 30, 11.8 | 75, 14.6 | 56, 14.6 | 109, 19.0 | 48, 12.1 | 129, 17.9 |
| n, %grades 9–11 | 13, 1.3 | 54, 3.0 | 7, 2.8 | 29, 5.6 | 5, 1.3 | 14, 2.4 | 1, .3 | 11, 1.5 |
| n, %high school | 77, 7.4 | 181, 10.0 | 29, 11.4 | 94, 18.3 | 25, 6.5 | 56, 9.8 | 23, 5.8 | 31, 4.3 |
| n, %some college | 11, 1.1 | 38, 2.1 | 3, 1.2 | 17, 3.3 | 5, 1.3 | 16, 2.8 | 3, .8 | 5, .7 |
| n, %college graduate | 24, 2.3 | 56, 3.1 | 11, 4.3 | 31, 6.0 | 5, 1.3 | 13, 2.3 | 8, 2.0 | 12, 1.7 |
| n, %beyond college graduate | 11, 1.1 | 56, 3.1 | 4, 1.6 | 36, 7.0 | 1, .3 | 7, 1.2 | 6, 1.5 | 13, 1.8 |
| n, %missing | 680, 65.8 | 972, 53.8 | 160, 63.0 | 221, 43.0 | 274, 71.5 | 340, 59.3 | 246, 62.0 | 411, 57.2 |
| Mother’s education n, %no formal education | 102, 9.9 | 158, 8.7 | 16, 6.3 | 11, 2.1 | 13, 3.4 | 16, 2.8 | 73, 18.4 | 131, 18.2 |
| n, %grades 1–8 | 184, 17.8 | 391, 21.7 | 37, 14.6 | 95, 18.5 | 79, 20.6 | 131, 22.9 | 68, 17.1 | 165, 22.9 |
| n, %grades 9–11 | 28, 2.7 | 53, 2.9 | 12, 4.7 | 23, 4.5 | 12, 3.1 | 21, 3.7 | 4, 1.0 | 9, 1.3 |
| n, %high school | 95, 9.2 | 225, 12.5 | 40, 15.7 | 114, 22.2 | 30, 7.8 | 87, 15.2 | 25, 6.3 | 24, 3.3 |
| n, %some college | 9, .9 | 37, 2.0 | 4, 1.6 | 21, 4.1 | 5, 1.3 | 15, 2.6 | 0, .0 | 1, .1 |
| n, %college graduate | 16, 1.5 | 43, 2.4 | 5, 2.0 | 18, 3.5 | 8, 2.1 | 19, 3.3 | 3, .8 | 6, .8 |
| n, %beyond college graduate | 6, .6 | 13, .7 | 3, 1.2 | 8, 1.6 | 1, .3 | 4, .7 | 2, .5 | 1, .1 |
| n, %missing | 594, 57.4 | 886, 49.1 | 137, 53.9 | 224, 43.6 | 235, 61.4 | 280, 48.9 | 222, 55.9 | 382, 53.1 |
| Parental occupation2 n, %low | 354, 34.2 | 698, 38.6 | 42. 16.5 | 133, 25.9* | 160, 41.8 | 249, 43.5 | 152, 38.3 | 316, 43.9 |
| n, %medium | 216, 20.9 | 413, 22.9 | 79, 31.1 | 127, 24.7 | 71, 18.5 | 129, 22.5 | 66, 16.6 | 157, 21.8* |
| n, %high | 175, 16.9 | 326, 18.1 | 70, 27.6 | 175, 34.0 | 36, 9.4 | 56, 9.8 | 69, 17.4 | 95, 13.2 |
| n, %missing | 289, 27.9 | 369, 20.4 | 63, 24.8 | 79, 15.4 | 116, 30.3 | 139, 24.3 | 110, 27.7 | 151, 21.0 |
| Siblings (n, % having more than 4) | 10, 1.0 | 94, 32.9 | 1, 0.4 | 11, 2.1 | 4, 1.0 | 23, 4.0 | 5, 1.3 | 60, 8.3 |
| n, %missing | 1004, 97.5 | 1514, 84.1 | 248, 97.6 | 422, 82.1 | 374, 97.7 | 501, 87.4 | 386, 97.2 | 597, 83.0 |
| Baseline cognition3 | ||||||||
| Global cognition (m, SD) | .10 (.53) | .33 (.53)* | .39 (.46) | .70 (.42)* | .14 (.48) | .34 (.48)* | −.12 (.51) | .05 (.47)* |
| Memory (m, SD) | .10 (.67) | .36 (.67)* | .29 (.69) | .69 (.63)* | .09 (.67) | .32 (.68)* | −.01 (.63) | .16 (.60)* |
| Language (m, SD) | .02 (.62) | .29 (.63)* | .35 (.65) | .72 (.55)* | .09 (.53) | .34 (.55)* | −.25 (.56) | −.06 (.53)* |
| Visuospatial (m, SD) | .14 (.62) | .31 (.58)* | .52 (.39) | .69 (.38)* | .20 (.55) | .35 (.49)* | −.17 (.66) | .02 (.61)* |
| Lost to follow-up (n, % of group total) | ||||||||
| Time 2 | 245, 23.7 | 427, 23.6 | 63, 24.8 | 101, 19.6 | 87, 22.7 | 133, 23.2 | 95, 23.9 | 193, 26.8 |
| Time 3 | 435, 42.1 | 734, 40.6 | 114, 44.9 | 192, 37.4 | 164, 42.8 | 229, 40.0 | 157, 39.5 | 313, 43.5 |
| Time 4 | 622, 60.2 | 1056, 58.5 | 166, 65.4 | 277, 53.9* | 231, 60.3 | 354, 61.8 | 225, 56.7 | 425, 59.1 |
| Time 5 | 771, 74.6 | 1312, 72.6 | 202, 79.5 | 367, 71.4* | 295, 77.0 | 434, 75.7 | 274, 69.0 | 511, 71.1 |
| Time 6 | 864, 83.6 | 1472, 81.5 | 224, 88.2 | 408, 79.4* | 321, 83.8 | 485, 84.6 | 319, 80.4 | 579, 80.5 |
Note. Chi-square and t-tests were used to compare cohorts
*
p < .05; m = mean, SD = standard deviation, CVD = cardiovascular disease (sum of diabetes, heart disease, hypertension, and stroke at baseline), CSES = childhood socio-economic status;
2
low: housewife/unskilled/semi-skilled, medium: skilled/clerical, high: manager/professional;
3
Cognitive factor scores are unadjusted for demographics