TABLE 3—
Rates of Coronary Heart Disease (CHD) and Stroke and Distributions of Other Characteristics, by Social Class at Birth: Participants in the Aberdeen Children of the 1950s Cohort
| Social Class Category at Birth | |||||||
| I/II (n = 1004) | III Nonmanual (n = 1207) | III Manual (n = 4882) | IV (n = 1567) | V (n = 1840) | Unemployed (n = 605) | Pa | |
| CHD rate per 10 000 PY (95% CI) | 8.3 (5.4, 13.8) | 9.8 (6.8, 14.8) | 11.0 (9.2, 13.3) | 11.5 (8.5, 16.0) | 20.5 (16.5, 25.8) | 12.0 (7.5, 20.4) | <.001 |
| Stroke rate per 10 000 PY (95% CI) | 2.3 (1.0, 6.9) | 3.0 (1.5, 6.8) | 4.2 (3.1, 5.6) | 3.4 (2.0, 5.6) | 7.8 (5.6, 11.3) | 5.2 (2.5, 12.5) | .001 |
| Combined CHD/stroke rate per 10 000 PY (95% CI) | 10.2 (6.7, 16.4) | 12.5 (9.0, 17.8) | 14.9 (12.7, 17.5) | 14.9 (11.4, 19.9) | 27.0 (22.4, 32.9) | 15.7 (10.3, 24.1) | <.001 |
| Gravidity ≥ 5, no. (%) | 51 (5.1) | 69 (5.7) | 432 (8.9) | 183 (11.7) | 341 (18.5) | 78 (12.9) | <.001 |
| Maternal height ≤ 152 cm, no. (%) | 119 (11.9) | 236 (19.6) | 1251 (25.6) | 481 (30.7) | 601 (32.7) | 192 (31.7) | <.001 |
| Maternal age at birth 15–19 y, no. (%) | 7 (0.7) | 33 (2.7) | 216 (4.4) | 71 (4.5) | 98 (5.3) | 82 (13.6) | <.001 |
| Birth outside marriage, no. (%) | 1 (0.1) | 2 (0.2) | 17 (0.4) | 10 (0.6) | 21 (1.1) | 448 (74.1) | <.001 |
| Gestational age < 37 wk, no. (%)b | 40 (4.2) | 77 (6.8) | 283 (6.4) | 121 (8.7) | 128 (8.1) | 38 (8.7) | <.001 |
| Birthweight z score, mean (SD) | 0.18 (0.98) | 0.08 (0.94) | −0.01 (0.98) | −0.02 (1.02) | −0.08 (1.01) | −0.13 (1.07) | <.001 |
| Weight at school entry z score, mean (SD) | 0.19 (0.86) | 0.07 (0.93) | −0.02 (0.88) | −0.06 (0.70) | −0.11 (0.82) | −0.04 (0.93) | <.001 |
| Height at school entry z score, mean (SD) | 0.37 (0.94) | 0.20 (0.92) | 0.01 (0.97) | −0.13 (0.86) | −0.25 (0.89) | −0.18 (1.0) | <.001 |
| University degree, no. (%)b | 335 (43.4) | 216 (27.1) | 475 (16.1) | 83 (9.1) | 68 (6.9) | 52 (17.1) | <.001 |
Note. PY = person-years; CI = confidence interval.
aTrend tests across occupational social class categories, not including unemployed category.
bNumber and percentage of those with complete data. For gestational age, the numbers in each social class category with complete data were as follows: I/II, 952; III nonmanual, 1134; III manual, 4455; IV, 1399; V, 1582; and unemployed, 438. The corresponding numbers for university degree were 707, 796, 2960, 913, 987, and 304.