Table 1.
Sample characteristics
| n | Exposed cohort | n | Unexposed cohort | |
|---|---|---|---|---|
| Age, years, mean (s.d.) | 13 570 | 28.9 (6.4) | 223 274 | 31.1 (5.5) |
| Ethnicity, n (%) | ||||
| White | 6759 (49.8) | 100 508 (45.0) | ||
| Mixed or multiple | 489 (3.6) | 7335 (3.3) | ||
| Asian/Asian British | 639 (4.7) | 18 908 (8.5) | ||
| Black/African/Caribbean/Black British | 13 570 | 2851 (21.0) | 223 274 | 51 149 (22.9) |
| Other ethnic group | 829 (6.1) | 16 542 (7.4) | ||
| Not stated | 2003 (14.8) | 28 812 (12.9) | ||
| Nicotine dependence in pregnancy, n (%) | ||||
| Noa | 12 266 (90.4) | 219 072 (98.1) | ||
| Yes | 13 570 | 1303 (9.6) | 223 274 | 4202 (1.9) |
| Index of Multiple Deprivation, n (%) | ||||
| Most deprived 10% | 1117 (8.3) | 15 461 (7.0) | ||
| Most deprived 10–30% | 6986 (51.8) | 97 554 (43.9) | ||
| Most deprived 30–50% | 13 490 | 3028 (22.4) | 222 179 | 54 986 (24.7) |
| Least deprived 30–50% | 1258 (9.3) | 25 505 (11.5) | ||
| Least deprived 10–30% | 827 (6.1) | 20 191 (9.1) | ||
| Least deprived 10% | 274 (2.0) | 8482 (3.8) | ||
a.
An absence of a nicotine dependence diagnosis recorded during the delivery episode was coded as ‘no’.