Table 1. Patient Characteristics by Cohort.
| Characteristic | No. (%) | |||||
|---|---|---|---|---|---|---|
| NCDS | BCS70 | |||||
| Total (n = 15 939)a | No atopic eczema (n = 13 278 [83.3%]) | Atopic eczema (n = 2661 [16.7%]) | Total (n = 14 966)a | No atopic eczema (n = 11 310 [75.6%]) | Atopic eczema (n = 3656 [24.4%]) | |
| Asthma | ||||||
| No | 12 633 (79.3) | 10 809 (81.4) | 1824 (68.5) | 11 996 (80.2) | 9359 (82.7) | 2637 (72.1) |
| Any | 3238 (20.3) | 2402 (18.1) | 836 (31.4) | 2300 (15.4) | 1355 (12.0) | 945 (25.8) |
| Missing | 68 (0.4) | 67 (0.5) | 1 (0) | 670 (4.5) | 596 (5.3) | 74 (2.0) |
| Rhinitis | ||||||
| No | 11 718 (73.5) | 10 140 (76.4) | 1578 (59.3) | 9624 (64.3) | 7836 (69.3) | 1788 (48.9) |
| Any | 4149 (26.0) | 3066 (23.1) | 1083 (40.7) | 5329 (35.6) | 3467 (30.7) | 1862 (50.9) |
| Missing | 72 (0.5) | 72 (0.5) | 0 (0) | 13 (0.1) | 7 (0.1) | 6 (0.2) |
| Sex | ||||||
| Male | 8200 (51.4) | 6996 (52.7) | 1204 (45.2) | 7716 (51.6) | 6110 (54.0) | 1606 (43.9) |
| Female | 7739 (48.6) | 6282 (47.3) | 1457 (54.8) | 7250 (48.4) | 5200 (46.0) | 2050 (56.1) |
| Ethnicity | ||||||
| White | 12 018 (75.4) | 9843 (74.1) | 2175 (81.7) | 11 790 (78.8) | 8758 (77.4) | 3032 (82.9) |
| Other | 160 (1.0) | 132 (1.0) | 28 (1.1) | 510 (3.4) | 389 (3.4) | 121 (3.3) |
| Missing | 3761 (23.6) | 3303 (24.9) | 458 (17.2) | 2666 (17.8) | 2163 (19.1) | 503 (13.8) |
| Region of residence in childhood | ||||||
| Southern England | 4871 (30.6) | 4014 (30.2) | 857 (32.2) | 4427 (29.6) | 3177 (28.1) | 1250 (34.2) |
| Central England | 4689 (29.4) | 3866 (29.1) | 823 (30.9) | 3454 (23.1) | 2555 (22.6) | 899 (24.6) |
| Northern England | 6379 (40.0) | 5398 (40.7) | 981 (36.9) | 4804 (32.1) | 3718 (32.9) | 1086 (29.7) |
| Missing | 0 (0) | 0 (0) | 0 (0) | 2281 (15.3) | 1860 (16.4) | 421 (11.5) |
| Social class in childhoodb | ||||||
| I/II | 4489 (28.2) | 3632 (27.4) | 857 (32.2) | 5281 (35.3) | 3780 (33.4) | 1501 (41.1) |
| IIIa/b | 9626 (60.4) | 8069 (60.8) | 1557 (58.5) | 8410 (56.2) | 6504 (57.5) | 1906 (52.1) |
| IV/V | 1718 (10.8) | 1479 (11.1) | 239 (9.0) | 1238 (8.3) | 995 (8.8) | 243 (6.6) |
| Missing | 106 (0.7) | 98 (0.7) | 8 (0.3) | 37 (0.2) | 31 (0.3) | 6 (0.2) |
| Household size | ||||||
| ≤3 Persons | 1211 (7.6) | 996 (7.5) | 215 (8.1) | 1339 (8.9) | 999 (8.8) | 340 (9.3) |
| >3 Persons | 12 357 (77.5) | 10 186 (76.7) | 2171 (81.6) | 11 374 (76.0) | 8471 (74.9) | 2903 (79.4) |
| Missing | 2371 (14.9) | 2096 (15.8) | 275 (10.3) | 2253 (15.1) | 1840 (16.3) | 413 (11.3) |
| Smoking during pregnancy | ||||||
| No | 10 482 (65.8) | 8690 (65.4) | 1792 (67.3) | 8050 (53.8) | 5963 (52.7) | 2087 (57.1) |
| Any | 5257 (33.0) | 4427 (33.3) | 830 (31.2) | 6847 (45.8) | 5293 (46.8) | 1554 (42.5) |
| Missing | 200 (1.3) | 161 (1.2) | 39 (1.5) | 69 (0.5) | 54 (0.5) | 15 (0.4) |
| Childhood smoke exposure | ||||||
| No | 2993 (18.8) | 2424 (18.3) | 569 (21.4) | 4340 (29.0) | 3165 (28.0) | 1175 (32.1) |
| Any | 7953 (49.9) | 6564 (49.4) | 1389 (52.2) | 8337 (55.7) | 6272 (55.5) | 2065 (56.5) |
| Missing | 4993 (31.3) | 4290 (32.3) | 703 (26.4) | 2289 (15.3) | 1873 (16.6) | 416 (11.4) |
| Parental history of atopy | ||||||
| No | NA | NA | NA | 8638 (57.7) | 6687 (59.1) | 1951 (53.4) |
| Any | NA | NA | NA | 2958 (19.8) | 1918 (17.0) | 1040 (28.4) |
| Missing | NA | NA | NA | 3370 (22.5) | 2705 (23.9) | 665 (18.2) |
| Birth weight, mean (SD), kg | 3.3 (0.5) | 3.3 (0.5) | 3.3 (0.5) | 3.3 (0.5) | 3.3 (0.5) | 3.3 (0.5) |
| Missing | 529 (3.3) | 445 (3.4) | 84 (3.2) | 14 (0.1) | 13 (0.1) | 1 (0.03) |
| Breastfeeding | ||||||
| No | 4435 (27.8) | 3742 (28.2) | 693 (26.0) | 7957 (53.2) | 6075 (53.7) | 1882 (51.5) |
| Any | 9583 (60.1) | 7832 (59.0) | 1751 (65.8) | 4659 (31.1) | 3323 (29.4) | 1336 (36.5) |
| Missing | 1921 (12.1) | 1704 (12.8) | 217 (8.2) | 2350 (15.7) | 1912 (16.9) | 438 (12.0) |
Abbreviations: BCS70, 1970 British Cohort Study; NA, not applicable; NCDS, National Childhood Development Study.
a
Number is based on patients with at least 1 response to an eczema question; missing refers to number of individuals without data on each covariate.
b
Registrar General’s social class: I, professional; II, managerial and technical; III, skilled; IV, partly skilled; V, unskilled.