Parental smoking during pregnancy according to maternal characteristics, Pelotas 1993 and 2004 birth cohort studies
| 1993 | 2004 | |||||||
|---|---|---|---|---|---|---|---|---|
| Maternal smoking | Paternal smoking | Maternal smoking | Paternal smoking | |||||
| Variables | No, n (%) | Yes, n (%) | No, n (%) | Yes, n (%) | No, n (%) | Yes, n (%) | No, n (%) | Yes, n (%) |
| Family income (quintiles) | p<0.001 | p<0.001 | p<0.001 | p<0.001 | ||||
| 1st (poorest) | 630 (17.9) | 439 (24.7) | 487 (16.8) | 556 (23.7) | 550 (17.7) | 338 (28.6) | 537 (18.1) | 351 (26.4) |
| 2nd | 770 (21.8) | 413 (23.3) | 600 (20.8) | 574 (24.4) | 562 (18.1) | 307 (25.8) | 544 (18.4) | 325 (24.5) |
| 3rd | 596 (16.9) | 351 (19.8) | 503 (17.4) | 435 (18.5) | 590 (19.0) | 241 (20.4) | 573 (19.4) | 258 (19.4) |
| 4th | 758 (21.5) | 300 (16.9) | 621 (21.5) | 430 (18.3) | 685 (22.1) | 178 (15.1) | 645 (21.8) | 218 (16.4) |
| 5th (better-off) | 776 (21.9) | 271 (15.3) | 680 (23.5) | 354 (15.1) | 717 (23.1) | 119 (10.1) | 660 (22.3) | 176 (13.3) |
| Marital status | p=0.001 | p<0.001 | p<0.001 | p<0.001 | ||||
| Single mother | 399 (11.3) | 255 (14.4) | 546 (18.9) | 104 (4.4) | 455 (14.7) | 255 (21.6) | 660 (22.3) | 50 (3.8) |
| With partner | 3131 (88.7) | 1519 (85.6) | 2345 (81.1) | 2245 (95.6) | 2649 (85.3) | 928 (78.4) | 2299 (77.7) | 1278 (96.2) |
| Schooling (years) | p<0.001 | p<0.001 | p<0.001 | p<0.001 | ||||
| 0–4 | 856 (24.3) | 636 (35.9) | 702 (24.3) | 760 (32.4) | 382 (12.4) | 284 (24.1) | 380 (13.0) | 286 (21.7) |
| 5–8 | 1612 (45.7) | 836 (47.1) | 1317 (45.6) | 1102 (46.9) | 1159 (37.8) | 602 (51.2) | 1140 (38.9) | 621 (47.1) |
| 9–11 | 719 (20.4) | 208 (11.7) | 592 (20.5) | 333 (14.2) | 1145 (37.3) | 250 (21.3) | 1059 (36.2) | 336 (25.5) |
| ≥12 | 337 (9.6) | 93 (5.3) | 276 (9.6) | 152 (6.5) | 382 (12.5) | 40 (3.4) | 347 (11.9) | 75 (5.7) |
| Age (years) | p=0.045 | p<0.001 | p=0.373 | p=0.293 | ||||
| ≤19 | 643 (18.2) | 280 (15.8) | 573 (19.8) | 339 (14.4) | 571 (18.4) | 240 (20.3) | 555 (18.8) | 256 (19.3) |
| 20–34 | 2485 (70.4) | 1304 (73.5) | 2038 (70.5) | 1709 (72.8) | 2111 (68.1) | 786 (66.4) | 2020 (68.2) | 877 (66.1) |
| ≥35 | 402 (11.4) | 189 (10.7) | 279 (9.7) | 301 (12.8) | 420 (13.5) | 157 (13.3) | 384 (13.0) | 193 (14.6) |
| Skin colour | p=0.006 | p=0.503 | p<0.001 | p<0.001 | ||||
| White | 2765 (78.3) | 1328 (74.9) | 2222 (76.9) | 1825 (77.7) | 2349 (75.7) | 773 (65.3) | 2196 (74.2) | 926 (69.7) |
| Black/mixed | 765 (21.7) | 444 (25.1) | 667 (23.1) | 524 (22.3) | 755 (24.3) | 410 (34.7) | 763 (25.8) | 402 (30.3) |
| Parity | p<0.001 | p<0.001 | p<0.001 | p<0.001 | ||||
| 0 | 1353 (38.7) | 490 (28.0) | 1186 (41.4) | 638 (27.5) | 1339 (43.1) | 345 (29.2) | 1287 (43.5) | 397 (29.9) |
| 1 | 994 (28.4) | 463 (26.4) | 799 (27.8) | 648 (27.9) | 834 (26.9) | 284 (24.0) | 786 (26.6) | 332 (25.0) |
| ≥2 | 1150 (32.9) | 799 (45.6) | 882 (30.8) | 1035 (44.6) | 930 (30.0) | 554 (46.8) | 885 (29.9) | 599 (45.1) |
| Height (m) | p=0.002 | p<0.001 | p=0.003 | p=0.004 | ||||
| Mean (SD) | 1.60 (0.07) | 1.59 (0.07) | 1.60 (0.07) | 1.59 (0.07) | 1.59 (0.06) | 1.58 (0.06) | 1.59 (0.06) | 1.58 (0.07) |
| Body mass index (kg/m2) | p<0.001 | p=0.810 | p<0.001 | p=0.946 | ||||
| Mean (SD) | 23.1 (3.8) | 22.2 (3.5) | 22.8 (3.7) | 22.8 (3.8) | 24.4 (4.6) | 23.7 (4.5) | 24.2 (4.5) | 24.2 (4.8) |
| Pregnancy duration (weeks) | p<0.001 | p<0.001 | p=0.028 | p=0.797 | ||||
| Mean (SD) | 38.1 (1.7) | 37.8 (1.8) | 38.1 (1.7) | 37.9 (1.8) | 38.5 (2.5) | 38.3 (3.0) | 38.4 (2.7) | 38.4 (2.7) |