Association of congenital microtia with environmental risk factors in South Korea

Background: Though there are reports regarding congenital microtia in various populations, few studies have focused on patients in South Korea. The objectives of the present study were to investigate the characteristics of microtia in South Korea and demonstrate the contribution of environmental risk factors to the occurrence of microtia. Patients and methods: We performed a retrospective chart review of congenital microtia patients who presented to our institution between January 2002 and December 2010. A case-control study was performed in 169 microtia patients and 128 controls to investigate the impact of environmental and prenatal factors on the development of congenital microtia. The data were gathered by personal interviews and detailed questionnaires filled out by the patients' parents. Results: A total of 374 microtia patients were included in the present study. Most cases were sporadic, and most were male. Unilateral microtia was more common, especially on the right side, while bilateral microtia occurred in only 25 patients. Two hundred forty-three patients had isolated microtia with no other congenital anomalies. In subgroups divided by type, lobule-type microtia was more common than concha-type microtia, and patients with anotia were the least common.Risk factors analyzed using multivariate regression models between groups, resident area during pregnancy, threatened abortion history, rubella vaccination, medication history during the first trimester, and alcohol consumption during the first trimester had significant impacts on the development of isolated microtia. Conclusions: The characteristics of congenital microtia in South Korea are similar to those in other populations, including the predominance of sporadic occurrence, male gender, lobule type, and isolated microtia. Several environmental risk factors can have significant impacts on the development of microtia.