Table 1 Prevalence of and characteristics (% of mean (SD)) by pre- and postnatal exposure to maternal smoking among children at 6.5 years of age
From: Exposure to parental smoking and child growth and development: a cohort study
| Â | Maternal smoking | Paternal postnatal smoking | ||||
|---|---|---|---|---|---|---|
| Â | Never smoking | Prenatal only | Postnatal only | Pre- and postnatal | Smoking | Nonsmoking |
|  | (n = 11,927) | (n = 72) | (n = 1,670) | (n = 220) | (n = 6,724) | (n = 4,295) |
Prevalence, % | 85.9 | 0.5 | 12.0 | 1.6 | 61.0 | 39.0 |
Child characteristics | Â | Â | Â | Â | Â | Â |
 Boys | 51.7 | 66.6 | 50.7 | 50.9 | 52.4 | 51.1 |
 Birthweight, g | 3452 (419) | 3415 (443) | 3377 (421) | 3300 (395) | 3445 (420) | 3471 (418) |
 Gestational weeks | 39.4 (1.0) | 39.3 (1.0) | 39.3 (1.0) | 39.5 (1.1) | 39.4 (1.0) | 39.4 (1.0) |
 Age at the follow-up, months | 79.3 (3.1) | 79.8 (3.2) | 79.2 (3.1) | 79.8 (3.2) | 79.4 (3.3) | 79.4 (3.3) |
Family characteristics | Â | Â | Â | Â | Â | Â |
 Maternal age, years | 24.7 (4.9) | 22.8 (4.5) | 23.1 (4.7) | 22.4 (4.4) | 25.2 (4.9) | 25.2 (4.9) |
 Paternal age, years | 27.6 (5.1) | 26.4 (5.3) | 26.4 (5.0) | 25.8 (4.9) | 27.3 (5.0) | 28.1 (5.1) |
 Maternal height, cm | 164.3 (5.5) | 164.6 (5.6) | 164.9 (5.7) | 164.9 (6.3) | 164.6 (5.5) | 164.6 (5.5) |
 Paternal height, cm | 176.0 (6.5) | 176.0 (6.3) | 176.0 (7.0) | 176.3 (6.7) | 175.7 (6.5) | 176.5 (6.5) |
 Maternal body mass index, kg/m2 | 24.6 (4.3) | 24.1 (4.3) | 23.5 (4.1) | 23.0 (3.6) | 24.5 (4.4) | 24.5 (4.4) |
 Paternal body mass index, kg/m2 | 25.7 (3.2) | 25.6 (3.2) | 25.1 (3.1) | 25.5 (4.1) | 26.2 (3.3) | 26.2 (3.3) |
 Maternal drinking during pregnancy | 1.7 | 29.1 | 2.4 | 19.0 | 1.9 | 1.4 |
 Marital status at birth |  |  |  |  |  |  |
  Married | 91.2 | 68.1 | 79.5 | 55.0 | 92.4 | 93.6 |
  Cohabitating | 5.8 | 19.4 | 12.8 | 23.6 | 5.6 | 4.4 |
  Single | 3.0 | 12.5 | 7.7 | 21.4 | 2.0 | 2.0 |
 Number of children at home |  |  |  |  |  |  |
  0 | 55.0 | 80.6 | 65.0 | 77.3 | 54.2 | 53.8 |
  1 | 36.0 | 12.5 | 28.5 | 18.6 | 36.4 | 37.6 |
  ≥2 | 9.0 | 6.9 | 6.5 | 4.1 | 9.4 | 8.5 |
 Maternal education |  |  |  |  |  |  |
  University degree | 14.3 | 8.3 | 6.7 | 4.1 | 11.5 | 19.6 |
  Some university | 51.6 | 52.8 | 48.0 | 41.8 | 50.9 | 53.3 |
  Secondary | 31.0 | 27.8 | 38.2 | 42.7 | 34.2 | 25.3 |
  < Secondary | 3.1 | 11.1 | 7.1 | 11.4 | 3.4 | 1.8 |
 Paternal education |  |  |  |  |  |  |
  University degree | 13.6 | 5.1 | 8.9 | 2.7 | 9.7 | 50.6 |
  Some university | 47.4 | 49.1 | 48.8 | 43.8 | 46.9 | 42.3 |
  Secondary | 36.9 | 39.0 | 38.6 | 43.3 | 41.0 | 30.9 |
  < Secondary | 2.1 | 6.8 | 3.7 | 10.2 | 2.4 | 1.2 |
 Maternal occupation |  |  |  |  |  |  |
  Non-manual | 45.8 | 29.2 | 31.3 | 17.7 | 42.4 | 52.8 |
  Manual | 33.9 | 20.8 | 33.9 | 31.8 | 37.3 | 27.9 |
  Unemployed | 20.3 | 50.0 | 34.8 | 50.5 | 20.2 | 19.3 |
 Paternal occupation |  |  |  |  |  |  |
  Non-manual | 29.0 | 18.1 | 23.1 | 15.0 | 25.1 | 36.5 |
  Manual | 55.4 | 43.1 | 49.0 | 42.3 | 60.7 | 49.0 |
  Unemployed | 12.5 | 19.4 | 19.6 | 24.5 | 12.0 | 12.1 |
  Don't know | 3.1 | 19.4 | 8.3 | 18.2 | 2.0 | 2.4 |
 Paternal smoking at the follow-up | 61.0 | 71.2 | 82.1 | 78.0 |  |  |
 Residence area, East | 47.2 | 60.7 | 57.9 | 56.8 | 45.8 | 45.0 |
Urban | 53.6 | 62.5 | 73.5 | 82.3 | 50.4 | 56.6 |