Risk factors and demographics for microtia in South America: A case–control analysis

Abstract

BACKGROUND The etiopathogenesis of microtia is still unknown in the majority of the cases, particularly for individuals presenting with isolated microtia. Our aim was to evaluate potential risk factors for this condition using a case-control approach. METHODS We analyzed data from 1,194 livebirths with isolated microtia enrolled in the ECLAMC study (Estudio Colaborativo Latino Americano de Malformaciones Congénitas) from 1982 to 2011 and their respective controls. Odds ratios were estimated with conditional logistic regression models along with 95% confidence intervals for the resulting odds ratio estimates controlling for the effects of potential confounders (sex, maternal age, hospital and year of birth) for an adjusted OR (aOR). RESULTS Multiparity was associated with a higher risk of microtia compared to primiparity (aOR 1.5, 95%CI 1.2–1.8), with women who had eight or more prior pregnancies having the highest risk (aOR 2.8, 95%CI 1.6–5.2). Women who presented with cold-like symptoms were at higher risk for microtia (aOR 2.2, 95%CI 1.2–3.9) as well as those that used tobacco or alcohol during pregnancy (aOR 1.7, 95%CI 1.1–2.5 and aOR 1.4, 95%CI 0.9–2.1, respectively). The association with alcohol use appeared to be limited to those women who reported binge drinking during pregnancy (aOR 1.4, 95% 0.7–2.9). Cases from hospitals at low altitude (< 2,500 m) tended to have more severe types of microtia than those from hospitals at high altitude. CONCLUSIONS These results support the hypothesis that in addition to teratogens other non-genetic risk factors contribute to the occurrence of isolated microtia.

Congenital Auricular Malformations: Description of Anomalies and Syndromes

“…4 High altitude, usually defined as above 2,500 m, can be associated with a higher prevalence of microtia as well as oral clefts, congenital heart disease, and limb defects [37][38][39] ; (data given for Quito, Ecuador [located at 2,850 m], La Paz, Bolivia [3,600 m], and Bogota, Colombia [2,640 m]). In contrast, Luquetti et al 40 compared severity of microtia in cases from hospitals at low and high altitudes and observed a tendency to more severe microtia in the former. The authors noted that it is important to highlight that in South America altitude and ancestry are strongly correlated; populations at high altitude have a much higher proportion of Native American and a much lower proportion of African ancestry than those at low altitude.…”

“…Thus, it remains unclear whether altitude is a risk factor, due to chronic exposure to hypoxia or different dietary habits, whether there is a genetic susceptibility related to ancestry, or whether there is a combined effect. 40 Embryology: Outer Ear Development…”

Phenotypic characterization and risk factors for microtia in East China, a case–control study

“…A detailed medical examination and retrospective chart review was performed for 911 patients with congenital microtia for phenotypic characterization study, who presented to our Eye & ENT Hospital of Fudan University between 2007 and 2013. Patients with microtia were considered isolated if they did not present any other malformation or if they only presented selected minor congenital malformation, like pre-auricular pit or pre-auricular tag [5]. Cases with microtia on one side and another selected minor ear malformation on the other side were categorized as unilateral.…”

A bioprinting printing approach to regenerate cartilage for microtia treatment

“…Several possibilities for the cause is suggested but still poorly understood. These include vertebrae abnormalities [8], medications [9,10], genetic disorders [11], and even illness during pregnancy [12]. There are two forms of microtia, unilateral or bilateral.…”