Descriptive epidemiology of anotia and microtia, Hawaii, 1986–2002

Abstract

The objective of this investigation was to describe the epidemiology of anotia and microtia with respect to various factors. The cases studied were all infants and fetuses with anotia or microtia identified by a population-based birth defects registry in Hawaii. The anotia and microtia rates were determined for selected factors and comparisons made among the subgroups by calculating the rate ratio (RR) and 95% confidence interval (CI). A total of 120 cases were identified, for a rate of 3.79 per 10,000 live births. The anotia and microtia rate increased during 1986-2002, although the trend was not significant (P = 0.715). Of 49 specific structural birth defects examined, four were found to be significantly more common in the presence of anotia and microtia. When compared with Caucasians, the anotia and microtia rates were higher among Far East Asians (RR 1.79, 95% CI 0.89-3.68), Pacific Islanders (RR 2.26, 95% CI 1.24-4.32), and Filipinos (RR 2.34, 95% CI 1.23-4.64). The defects were less common among females (RR 0.64, 95% CI 0.43-0.93) and more common with multiple birth (RR 3.72, 95% CI 1.66-7.33), birth weight < 2500 g (RR 3.35, 95% CI 2.04-5.30), and gestational age <38 weeks (RR 2.27, 95% CI 1.49-3.40). In conclusion, the rate for anotia and microtia increased in Hawaii during the study period. The rates for only a few structural birth defects were substantially greater than expected in association with anotia and microtia. Anotia and microtia rates varied significantly according to maternal race/ethnicity, infant sex, plurality, birth weight, and gestational age.

Prevalence at birth of congenital abnormalities of external ears in Hungary

“…The mild male excess of cases with isolated ear CAs in the study was in agreement with the results of some previous studies [11,13,15,[18][19][20][21][22][23], though the cases with isolated microtia/anotia in the Italian registry did not show a male predominance [24]. The strong male excess in cases with unclassified multiple ear CA is worth mentioning, because in general previous studies did not have strict differentiation between cases with isolated and multiple ear CAs.…”

“…The obvious predominance of unilateral cases and among them a slight right side excess in cases with isolated microtia/anotia in our study corresponded to the previous observations in other studies/countries [11,13,15,[18][19][20][21][22][23][24][25].…”

Epidemiologic features and clinical subgroups of anotia/microtia in Texas

“…With respect to the descriptive epidemiology of anotia and/or microtia, associations have been reported between anotia and/or microtia and high maternal age (Harris et al, 1996;Forrester and Merz, 2005), high maternal parity (Castilla and Orioli, 1986;Mastroiacovo et al, 1995;Harris et al, 1996;Forrester and Merz, 2005), race (Harris et al, 1996;Shaw et al, 2004;Forrester and Merz, 2005;Husain et al, 2008), sex (Harris et al, 1996;Sanchez et al, 1997;Shaw et al, 2004, Forrester andMerz, 2005), low maternal education (Shaw et al, 2004;Husain et al, 2008), prenatal drug exposure (Castilla and Orioli, 1986), advanced paternal age (Castilla and Orioli, 1986), low birth weight (Mastroiacovo et al, 1995;Forrester and Merz, 2005), gestational age (Forrester and Merz, 2005), and maternal diabetes (Mastroiacovo et al, 1995;Correa et al, 2008). Conflicting studies report significant or no significant association with maternal or paternal education (Castilla and Orioli, 1986;Mastroiacovo et al, 1995;Shaw et al, 2004), maternal acute or chronic illness (Castilla and Orioli, 1986), vaginal bleeding (Castilla and Orioli, 1986), residence at the time of delivery (Forrester andMerz, 2005, Husain et al, 2008), and gestational age (Castilla and Orioli, 1986).…”

“…There have been five other population-based descriptive studies of anotia/microtia, including in three U.S. states: California, Hawaii, and Texas (Mastroiacovo et al, 1995;Harris et al, 1996;Shaw et al, 2004;Forrester and Merz, 2005;Husain et al, 2008). From these five studies, anotia/microtia prevalence ranged from 0.76 per 10,000 births in France (Harris et al, 1996) to 2.77 per 10,000 live births in Texas (Husain et al, 2008), but on average 1.84 per 10,000 births (Harris et al, 1996).…”

Association of microtia with maternal obesity and periconceptional folic acid use

“…There is a paucity of epidemiologic information about this condition, and most previous studies have been descriptive. These studies have revealed that risk factors for microtia include advanced maternal age [Harris et al, 1996;Forrester and Merz, 2005;Canfield et al, 2009], male sex [Harris et al, 1996;Shaw et al, 2004;Canfield et al, 2009], low maternal education [Shaw et al, 2004;Husain et al, 2008;Canfield et al, 2009], and Hispanic ethnicity [Harris et al, 1996;Shaw et al, 2004;Forrester and Merz, 2005;Husain et al, 2008;Canfield et al, 2009]. Proposed etiologies include hypoxia [Castilla et al, 1999], in utero exposure to thalidomide [Buyse, 1990;Carey, 1993], maternal influenza [Lopez-Camelo and Orioli, 1996], and maternal diabetes [Mastroiacovo et al, 1995;EwartToland et al, 2000;Correa et al, 2008].…”