Socio-demographic determinants of hearing impairment studied in 103 835 term babies

Background: Serious hearing problems appear in approximately one in 1000 newborns. In 2000, the Joint Committee on Infant Hearing defined a list of risk factors for neonatal hearing impairment relating to health, physical characteristics and family history. The aim of this study is to determine which personal, environmental and social factors are associated with the prevalence of congenital hearing impairment (CHI). Methods: The entire population of 103 835 term newborns in Flanders, Belgium, was tested by a universal neonatal hearing screening (UNHS) programme using automated auditory brainstem responses (AABR). In the case of a positive result, a CHI diagnosis was verified in specialized referral centres. Socio-demographic risk factors were investigated across the entire population to study any relationship with CHI. Results: The prevalence of bilateral CHI of 35 dB nHL (normal hearing level) or more was 0.87/1000 newborns. The sensitivity and specificity of the screening test were 94.02 and 99.96%, respectively. The socio-demographic factors of gender, birth order, birth length, feeding type, level of education and origin of the mother were found to be independent predictors of CHI. Conclusions: The socio-demographic factors found to be associated with CHI extend the list of classic risk factors as defined by the American Academy of Pediatrics (AAP). Assessment of these additional factors may alert the treating physician to the increased risk of newborn hearing impairment and urge the need for accurate follow-up. Moreover, this extended assessment may improve decision making in medical practice and screening policy.