Characteristics of women living in Scotland at recruitment to the RCGP Oral Contraception Study, by smoking status
| Characteristic | All women (N = 4121) | Number of cigarettes smoked daily at recruitment | |||
|---|---|---|---|---|---|
| Non-smokers (n = 2063) | <15 (n = 1142) | ≥15 (n = 916) | P-value | ||
| Social class, n (%) | |||||
| Manual | 2910 (70.6) | 1341 (65.0) | 856 (75.0) | 713 (77.8) | <0.001 |
| Non-manual | 1211 (29.4) | 722 (35.0) | 286 (25.0) | 203 (22.2) | |
| Parity, n (%) | |||||
| 0 | 629 (15.3) | 357 (17.3) | 147 (12.9) | 125 (13.6) | <0.001 |
| 1 | 946 (23.0) | 464 (22.5) | 285 (25.0) | 197 (21.5) | |
| 2 | 1263 (30.6) | 656 (31.8) | 352 (30.8) | 255 (27.8) | |
| ≥3 | 1283 (31.1) | 586 (28.4) | 358 (31.3) | 339 (37.0) | |
| Contraceptive pill use status, n (%) | |||||
| Never used | 1918 (46.5) | 1020 (49.4) | 527 (46.1) | 371 (40.5) | <0.001 |
| Ever used | 2203 (53.5) | 1043 (50.6) | 615 (53.9) | 545 (59.5) | |
| Age, median (IQR), years | 28 (24–33) | 28 (24–34) | 28 (23–33) | 28 (24–34) | 0.321 |
↵IQR = interquartile range.