Table 5.
Risks for fetal CHD subtypes in different fetal placental tissue cobalt levels
| Group | Total tissue Ni | Tissue low, n = 131 (< 39.853 ng/g) | Tissue medium, n = 131 (39.853–75.894 ng/g) | Tissue high, n = 131 (> 75.894 ng/g) |
|---|---|---|---|---|
| Control (n ) | 212 | 109 | 58 | 45 |
| All cases (n ) | 181 | 22 | 73 | 86 |
| cOR | 2.850*** | Reference | 6.236*** | 9.469*** |
| aOR | 1.017*** | Reference | 5.777*** | 8.162*** |
| 95% CI | 1.010–1.024 | 3.185–10.480 | 4.379–15.212 | |
| Case with septal defects (n ) | 124 | 14 | 46 | 64 |
| cOR | 2.895*** | Reference | 6.175*** | 11.073*** |
| aOR | 1.017*** | Reference | 5.846*** | 9.230*** |
| 95% CI | 1.010–1.024 | 2.904–11.769 | 4.519–13.347 | |
| Case with conotruncal defects (n ) | 96 | 14 | 38 | 44 |
| cOR | 2.568*** | Reference | 5.101*** | 7.613*** |
| aOR | 1.015*** | Reference | 4.853*** | 6.354*** |
| 95% CI | 1.007–1.022 | 2.380–9.896 | 3.025–13.347 | |
| Case with right ventricular outflow tract obstruction (n ) | 65 | 5 | 21 | 39 |
| cOR | 3.610*** | Reference | 7.893*** | 18.893*** |
| aOR | 1.022*** | Reference | 8.014*** | 19.164*** |
| 95% CI | 1.013–1.031 | 2.800–22.933 | 6.723–54.632 | |
| Case with left ventricular outflow tract obstruction (n ) | 29 | 4 | 12 | 13 |
| cOR | 2.454*** | Reference | 5.638** | 7.872** |
| aOR | 1.012*** | Reference | 5.551*** | 7.550*** |
| 95% CI | 1.003–1.021 | 1.669–18.465 | 2.112–26.995 | |
| Case with anomalous pulmonary venous return (n ) | 26 | 5 | 9 | 12 |
| cOR | 2.301*** | Reference | 3.383* | 5.813** |
| aOR | 1.013*** | Reference | 3.023** | 4.589*** |
| 95% CI | 1.004–1.023 | 0.938–9.740 | 1.436–14.664 | |
| Case with other heart defects (n ) | 32 | 1 | 21 | 10 |
| cOR | 2.695*** | Reference | 39.466*** | 24.222** |
| aOR | 1.013** | Reference | 36.664*** | 22.082** |
| 95% CI | 1.004–1.022 | 4.727–284.371 | 2.636–184.948 |
n number, aOR adjusted odds ratio, cOR crude odds ratio
Logistic regression was used to calculate odds ratios and 95% CIs; the low-medium-high concentration of cobalt are referring to the tertiles and lose-dose group of cobalt was consider as a reference; all models were adjusted for maternal age, gestational age, education, taking folic acid (yes, no), parental smoking (yes, no), maternal pre-pregnancy BMI and iron, and calcium concentration. Significant differences between the mothers of case and control were indicated by the following: *P < 0.05, ***P < 0.001 or **P < 0.01