Investigation of the Risk Factors for Congenital Hypothyroidism in Iran: A Population-Based Case-Control Study

Background Congenital hypothyroidism (CH) is one of the most common causes of mental disability, which can be prevented in the case of early diagnosis and treatment. We aimed to study the some relevant risk factors for CH in neonates born in Khorasan Razavi Province, Iran. Materials and Methods: This was a population-based case-control study conducted on 97,380 neonates.The study population consisted of neonates born from April, 2016 to March, 2018 and undergone a screening program for CH.Overall, 530 neonates diagnosed with CH by a specialist were assigned to a case group and the remaining were considered as controls. Information was extracted from the Sina Electronic Health Record System (SinaEHR®, Iran). Bivariate and multivariate logistic regressions were carried out to determine the associations between independent variables and CH. Results: Of the 97,380 neonates, the case and control groups included 530 (248 females) and 96,860 (47,061 males) newborns, respectively. In multivariate analysis, the use of neonate formula (adjusted odds ratio [AOR]=0.63; 95% confidence interval [CI]: 0.43-0.93, P=0.02), medication during pregnancy (AOR=1.29; 95% CI: 0.86-1.94, P=0.23), maternal hypertension (AOR=3.25; 95% CI: 1.15-9.19, P=0.03), maternal depression (AOR=2.19; 95% CI: 1.16-4.14, P=0.02), maternal diabetes (AOR=0.65; 95% CI: 0.51-0.83, P=0.001), consanguineous marriage (AOR=1.34; 95% CI:1.12-1.60, P=0.002), place of residence, and birth season after adjusting for confounding variable remained in the final model. Conclusion: The study findings showed that birth season, place of residence, maternal hypertension and depression, and consanguineous marriage can be the main risk factors for CH. However, further studies are needed to analyze the findings of the present study to be more confident about the causality of these relationships.