Table 2 Effect estimates of the smoking variables regressed on the genetic instrument as shown in Eq. (1). The analysis is adjusted for offspring sex and the principal components (and genetic batch variables in MoBa). For the first 4 rows a logistic regression is used due to the smoking variables being binary. The effect estimate in the first column gives the odds of continuing smoking in pregnancy per additional risk allele of rs1051730. For the last 4 rows a linear regression is used. The effect estimate in the first column gives the change in the number of cigarettes smoked per day per each additional risk allele of rs1051730
From: Smoking during pregnancy and its effect on placental weight: a Mendelian randomization study
Smoking variable | Effect Estimate | Lower 95% CI | Higher 95% CI | P-value | F-statistic | N | Study |
|---|---|---|---|---|---|---|---|
Smoking in the first three months of pregnancy | 1.27 | 1.11 | 1.46 | 0.0009 | 11.1 | 2346 | ALSPAC |
Smoking in the last two weeks of pregnancy | 1.25 | 1.09 | 1.43 | 0.0015 | 10 | 2032 | ALSPAC |
Smoking at the beginning of pregnancy | 1.15 | 1.04 | 1.27 | 0.0016 | 9.9 | 4711 | MoBa |
Smoking at the end of pregnancy | 1.27 | 1.13 | 1.43 | 0.00004 | 17.1 | 4576 | MoBa |
# of cigarettes smoked per day in the first three month | 0.88 | 0.23 | 1.338 | 0.0001 | 14.7 | 2312 | ALSPAC |
# of cigarettes smoked per day in the last two weeks | 0.87 | 0.25 | 1.36 | 0.0004 | 12.7 | 2025 | ALSPAC |
# of cigarettes smoked per day at the beginning | 0.45 | 0.11 | 0.67 | 0.00003 | 17.2 | 4360 | MoBa |
# of cigarettes smoked per day at the end | 0.25 | 0.06 | 0.37 | 0.00006 | 16 | 4440 | MoBa |