Table 2.
Multinomial logistic regression models of selected environmental risk factors in the control and congenital heart defect (CHD) sub-groups (septal, left ventricular outflow tract obstruction [LVOTO], and conotruncal). OR, odds ratio; CI, confidence interval.
| Variable | Control vs. Septal | Control vs. LVOTO | Control vs. Conotruncal | |||
|---|---|---|---|---|---|---|
| OR (95% CI) ‡ | p adj‡ | OR (95% CI) ‡ | p adj‡ | OR (95% CI) ‡ | p adj‡ | |
| Child gender | ||||||
| Male † vs. female | 2.1 (1.1–4.1) | 0.035 | 0.2 (0.1–0.7) | 0.011 | 0.4 (0.1–1.2) | 0.094 |
| Maternal smoking status | ||||||
| Non-smoker † vs. smoker | 7.3 (2.1–24.9) | 0.002 | 2.9 (0.7–11.8) | 0.139 | 7.7 (1.8–31.9) | 0.005 |
| Non-smoker † vs. ex-smoker | 2.7 (1.1–6.5) | 0.029 | 0.7 (0.2–2.1) | 0.523 | 1.4 (0.4–5.0) | 0.561 |
| Maternal education | ||||||
| MSc, PhD † vs. elementary school | 6.1 (0.5–72.3) | 0.154 | 4.1 (0.1–127) | 0.415 | 1.4 (0.04–45.1) | 0.865 |
| MSc, PhD † vs. vocational school | 2.4 (0.4–13.1) | 0.311 | 3.7 (0.3–47.9) | 0.312 | 3.2 (0.3–30.7) | 0.309 |
| MSc, PhD † vs. high school | 2.8 (0.3–23.4) | 0.345 | 2.8 (0.1–75.6) | 0.549 | NA | |
| MSc, PhD † vs. college | 4.6 (0.8–26.7) | 0.090 | 3.9 (0.2–65.9) | 0.339 | 0.7 (0.04–13.9) | 0.812 |
| MSc, PhD † vs. university | 1.6 (0.3–8.6) | 0.560 | 2.8 (0.2–35.8) | 0.418 | 0.7 (0.06–7.2) | 0.737 |
| No. of live births | 1.8 (1.2–2.6) | 0.004 | 2.1 (1.4–3.3) | 0.001 | 1.9 (1.1–3.1) | 0.017 |
| Family anamnesis of CHD | ||||||
| Negative † vs. Positive | 9.3 (2.3–37.0) | 0.002 | 18.9 (3.8–90.9) | 0.0003 | 11.1 (2.1–58.8) | 0.005 |
| Maternal chronic disease | ||||||
| No † vs. Yes | 2.8 (1.0–7.4) | 0.043 | 3.6 (0.9–13.9) | 0.062 | 0.9 (0.2–5.5) | 0.921 |
| Other drugs in pregnancy | ||||||
| No † vs. Yes | 2.0 (1.0–4.1) | 0.055 | 3.6 (0.9–13.9) | 0.062 | 0.9 (0.2–5.5) | 0.921 |
| Folate supplement initiation | ||||||
| No folate suppl. † vs. before 3 weeks post-conception | 0.3 (0.1–0.7) | 0.010 | 0.2 (0.05–0.7) | 0.011 | 0.6 (0.2–2.1) | 0.394 |
| No folate suppl. † vs. after 3 weeks post-conception | 0.4 (0.1–1.1) | 0.067 | 0.5 (0.1–2.0) | 0.350 | 0.4 (0.1–2.0) | 0.286 |
| Folic acid intake per month (mg) | 1.0 (1.0–1.0) | 0.069 | 1.0 (1.0–1.0) | 0.417 | 1.0 (1.0–1.0) | 0.071 |
† Reference category. ‡ Odds ratio (OR), 95% confidence interval (CI), and adjusted p values were calculated in multinomial logistic regression models for mothers and children separately. Only variables with unadjusted p values < 0.250 were included in the multinomial logistic regression models and adjusted for co-variables. Variables with high levels of correlation were not included in the same model. NA: not applicable (the variable was not tested in the specific model).