Sociodemographic, health behavioral, and clinical risk factors for anotia/microtia in a population-based case-control study

Int J Pediatr Otorhinolaryngol. 2019 Jul:122:18-26. doi: 10.1016/j.ijporl.2019.03.026. Epub 2019 Mar 23.

Abstract

Objective: Anotia and microtia are congenital malformations of the external ear with few known risk factors. We conducted a comprehensive assessment of a wide range of potential risk factors using data from the National Birth Defects Prevention Study (NBDPS), a population-based case-control study of non-chromosomal structural birth defects in the United States.

Methods: Mothers of 699 infants with anotia or microtia (cases) and 11,797 non-malformed infants (controls) delivered between 1997 and 2011 were interviewed to obtain information about sociodemographic, health behavioral, and clinical characteristics. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated with logistic regression.

Results: Infants with anotia/microtia were more likely to be male (aOR, 1.29; 95% CI, 1.10-1.50) and from a multifetal pregnancy (aOR, 1.68; 95% CI, 1.16-2.42). Cases were also more likely to have parents of Hispanic ethnicity (maternal aOR, 3.19; 95% CI, 2.61-3.91; paternal aOR, 2.11; 95% CI, 1.54-2.88), and parents born outside the United States (maternal aOR, 1.29; 95% CI, 1.06-1.57; paternal aOR, 1.92; 95% CI, 1.53-2.41). Maternal health conditions associated with increased odds of anotia/microtia included obesity (aOR, 1.31; 95% CI, 1.06-1.61) and pre-pregnancy diabetes (type I aOR, 9.89; 95% CI, 5.46-17.92; type II aOR, 4.70; 95% CI, 2.56-8.63). Reduced odds were observed for black mothers (aOR, 0.57; 95% CI, 0.38-0.85) and mothers reporting daily intake of folic acid-containing supplements (aOR, 0.59; 95% CI, 0.46-0.76).

Conclusion: We identified several risk factors for anotia/microtia, some which have been previously reported (e.g., diabetes) and others which we investigate for perhaps the first time (e.g., binge drinking) that warrant further investigation. Our findings point to some potentially modifiable risk factors and provide further leads toward understanding the etiology of anotia/microtia.

Keywords: Anotia; Birth defect; Congenital malformation; Ear; Microtia.

MeSH terms

  • Adult
  • Black or African American / statistics & numerical data
  • Case-Control Studies
  • Congenital Microtia / epidemiology*
  • Congenital Microtia / ethnology
  • Diabetes Mellitus / epidemiology*
  • Dietary Supplements
  • Ear, External / abnormalities
  • Fathers / statistics & numerical data
  • Female
  • Folic Acid / therapeutic use
  • Health Behavior
  • Hispanic or Latino / statistics & numerical data
  • Humans
  • Infant, Newborn
  • Male
  • Mothers / statistics & numerical data
  • Obesity / epidemiology
  • Pregnancy
  • Pregnancy, Multiple
  • Protective Factors
  • Risk Factors
  • Sex Factors
  • United States / epidemiology

Substances

  • Folic Acid

Supplementary concepts

  • Microtia-Anotia