Environmental Risk Factors for Congenital Heart Disease in the Shandong Peninsula, China: A Hospital-based Case–Control Study

Abstract

BACKGROUND: In China, and in Shandong province, the proportionate contribution of birth defects to infant mortality has increased, and congenital heart disease (CHD) is now the most common cause of birth defects. The cause of approximately 90% of cases of congenital heart disease is multifactorial. Little is known about modifiable environmental risk factors or regional differences. We investigated putative environmental risk factors for congenital heart disease in the Shandong province of China in order to improve prevention of CHD. METHODS: We conducted a hospital-based 1:2 matched case-control study of 164 patients with congenital heart diseases and 328 controls, all of whom were retrospectively interviewed. Univariate and multivariate analyses were conducted to identify environmental risk factors for CHD. RESULTS: The environmental risk factors associated with CHD were mother's education level (odds ratio [OR], 0.31; 95% confidence interval [CI], 0.15-0.67), neonatal asphyxia or hypoxia (OR, 3.74; 95% CI, 1.25-11.18), number of previous pregnancies (OR, 2.68; 95% CI, 1.44-4.97), maternal upper respiratory tract infection (OR, 4.12; 95% CI, 1.56-10.85), maternal infection (OR, 7.98; 95% CI, 2.14-29.72), maternal B-mode ultrasound examination (OR, 4.05; 95% CI, 1.48-11.08), and maternal mental stress (OR, 3.93; 95% CI, 1.94-7.94) during early pregnancy. No significant interactions were observed among these factors. CONCLUSIONS: Augmenting maternal mental healthcare, obtaining regular health counseling and testing during pregnancy, preventing upper respiratory tract infections, limiting medication during early pregnancy, offering health promotion and health education to women of childbearing age (especially those with less formal education), and improving obstetric procedures and techniques may lower the occurrence of congenital heart disease.