Table 4.
Observational and Mendelian randomization analyses for continuing to smoke during pregnancy in mothers of European ancestry with rs1051730 genotype
| n | Class | P-valueb | ||||
|---|---|---|---|---|---|---|
| Non-smokers | Experimenters | Late onset | Early onset | |||
| OR (95% CI) | OR (95% CI) | OR (95% CI) | OR (95% CI) | |||
| Observational | ||||||
| Smokers pre-pregnancy (unadjusted) | 975 | 1 | 1.05 (0.66, 1.68) | 1.68 (1.01, 2.81) | 3.62 (1.53, 8.57) | 0.002 |
| Smokers pre-pregnancy (adjusted)a | 975 | 1 | 1.09 (0.68, 1.76) | 1.65 (0.97, 2.79) | 3.18 (1.32, 7.67) | 0.01 |
| Mendelian randomization | ||||||
| Non-smokers pre-pregnancy | 3133 | 1 | 1.06 (0.88, 1.28) | 0.90 (0.72, 1.12) | 0.92 (0.63, 1.34) | 0.67 |
| Smokers pre-pregnancy | 1020 | 1 | 0.95 (0.69, 1.30) | 1.16 (0.86, 1.57) | 1.36 (0.92, 2.00) | 0.35 |
Odds ratios (ORs) for observational analysis represent relative differences of offspring smoking class membership for mothers who continue to smoke during pregnancy compared to those who quit smoking during pregnancy. ORs for Mendelian randomization analysis represent relative differences of offspring smoking class membership per each additional minor (risk) allele of rs1051730. Samples restricted to mothers of European ancestry with rs1051730 genotype data. aAdjusted for sex, maternal age, parity, maternal educational attainment, crowding and housing tenure. bP-value for overall association of the exposure with the outcome from Likelihood Ratio Test. CI = confidence interval.