[A nested case-control study on the association of neonatal cord blood selenium, iron and copper with congenital heart disease].

Objective

To investigate the relationship between the levels of selenium, iron and copper in cord blood of neonates and the risk of congenital heart disease (CHD), and analyze their interaction effects.

Methods

The subjects were obtained from the birth cohort in Lanzhou area established from 2010 to 2012. A baseline survey was conducted in the first trimester, and the follow-up was conducted in the second trimester, third trimester and 42 days after delivery. The umbilical vein blood was collected from newborns at delivery, and information on their birth outcomes was extracted from medical records. A nested case-control study was used to select 97 neonates with CHD newly diagnosed by echocardiography as the case group, and 194 neonates were selected as the control group by 1∶2 matching according to their mother's age, block and CHD onset time. Inductively coupled ion mass spectrometry was used to detect the concentrations of selenium, iron and copper in neonatal cord blood. The element exposure was categorized into three groups, the low, medium and high concentrations, according to the quartiles Q1 and Q3 of selenium, iron and copper concentrations in the control group. The association between cord blood selenium, iron and copper concentrations and CHD was analyzed by conditional logistic regression model using medium concentration as the reference standard. The association of their interactions with CHD was analyzed by a phase multiplication model.

Results

The M (Q1, Q3) concentration of neonatal cord blood copper was 746.12 (467.48, 759.74) μg/L in the case group and 535.69 (425.21, 587.79) μg/L in the control group, with a statistically significant difference between the two groups (P<0.05). After adjustment for confounders, logistic regression models showed that the risk of CHD development was increased in neonates with either high copper in cord blood (OR=4.062, 95%CI: 2.013-8.199) or high copper combined with high iron (OR=3.226, 95%CI: 1.343-7.750). No correlation was observed between selenium and iron concentrations and the development of CHD in neonates. There was a multiplicative interaction between copper and iron in cord blood on the risk of developing CHD (OR=1.303, 95%CI: 1.056-1.608).

Conclusion

There is a multiplicative interaction between iron and copper elements. The high copper and the high copper combined with high iron in umbilical cord blood are risk factors for neonatal CHD.