Table 1.
—Risk of Doctor-Diagnosed Asthma by Age 7 y Among Children Whose Mothers Smoked During Pregnancy, According to Whether the Grandmother Smoked During the Pregnancy Resulting in the Parent of the Study Child
| Statistical Modelsa | PGM + M + vs PGM−M+ | MGM+M+ vs MGM−M+ |
| Boys and girls | ||
| No. | 88 of 507 (PGM+M+), 94 of 540 (PGM−M+) | 112 of 655 (MGM+M+), 126 of 770 (MGM−M+) |
| Unadjusted | 1.00 (0.72-1.37) | 1.05 (0.80-1.39) |
| Model I | 1.02 (0.73-1.41) | 1.05 (0.79-1.39) |
| Model II | 0.99 (0.69-1.40) | 1.09 (0.79-1.50) |
| Model III | 0.94 (0.65-1.34) | 1.08 (0.78-1.51) |
| Boys only | ||
| No. | 51 of 252 (PGM+M+), 50 of 279 (PGM−M+) | 65 of 348 (MGM+M+), 70 of 389 (MGM−M+) |
| Unadjusted | 1.16 (0.75-1.79) | 1.05 (0.72-1.52) |
| Model I | 1.19 (0.76-1.85) | 1.02 (0.69-1.49) |
| Model II | 1.18 (0.73-1.90) | 1.12 (0.73-1.72) |
| Model III | 1.07 (0.65-1.76) | 1.10 (0.71-1.72) |
| Girls only | ||
| No. | 37 of 255 (PGM+M+), 44 of 261 (PGM−M+) | 47 of 307 (MGM+M+), 56 of 381 (MGM−M+) |
| Unadjusted | 0.84 (0.52-1.35) | 1.05 (0.69-1.60) |
| Model I | 0.84 (0.52-1.37) | 1.09 (0.71-1.68) |
| Model II | 0.86 (0.51-1.46) | 1.05 (0.65-1.71) |
| Model III | 0.84 (0.49-1.44) | 1.07 (0.64-1.78) |
Data shown are OR with 95% CI using the nonsmoking grandparents as the reference. M = mother; MGM = maternal grandmother; − = did not smoke during pregnancy; PGM = paternal grandmother; + = smoked during pregnancy.
No. indicates the proportion of children who were given the diagnosis of asthma. Model I adjusts for family history of asthma; Model II additionally adjusts for gestation, parity, maternal education, breastfeeding, and the amount the mother smoked during pregnancy; Model III, in addition, adjusted for paternal smoking in pregnancy and exposure of the child to environmental tobacco smoke at two time points.