Risk factors for hearing loss in neonates

Background An estimated 6 of 1,000 children with live births suffer from permanent hearing loss at birth or the neonatal period. At least 90% of cases occur in developing countries. Hearing loss should be diagnosed as early as possible so that intervention can be done before the age of 6 months. Objective To determine risk factors for hearing loss in neonates. Methods We performed a case-control study involving 100 neonates with and without hearing loss who were born at Sanglah Hospital, Denpasar from November 2012 to February 2013. Subjects were consisted of 2 groups, those with hearing loss (case group of 50 subjects) and without hearing loss (control group of 50 subjects). The groups were matched for gender and birth weight. We assessed the following risk factors for hearing loss: severe neonatal asphyxia, hyperbilirubinemia, meningitis, history of aminoglycoside therapy, and mechanical ventilation by Chi-square analysis. The results were presented as odds ratio and its corresponding 95% confidence intervals. Results Seventy percent of neonates with hearing loss had history of aminoglycoside therapy. Multivariable analysis revealed that aminoglycoside therapy of 14 days or more was a significant risk factor for hearing loss (OR 2.7; 95%CI 1.1 to 6.8; P=0.040). There were no statistically significant associations between hearing loss and severe asphyxia, hyperbilirubinemia, meningitis, or mechanical ventilation. The Indonesian Health Surveys (1993-1996) in 8 provinces on loss of hearing reported a prevalence of 0.4% for deafness and 16.8% for hearing loss (HL). The toddler age group had a deafness prevalence of about 0.4%, higher than the pre-school and school aged groups. Early identification of HL is important, as the ages of 0 to 6 years are a critical period of speech and language development.1,2 Sensorineural HL and deafness occur in 2 to 4% of neonates who receive treatment in neonatal intensive care unit (NICU). This incidence of HL is higher than in normal neonates, but the underlying cause is still controversial.3 Some proposed risk factors for congenital or acquired neonatal HL include family history of permanent sensorineural HL, craniofacial anomalies, intrauterine infections, physical anomalies or other related syndrome, birth weight <1,500 grams, low Apgar scores (0-3 at 5 minutes, or 0-6 at 10 minutes), NICU admission, respiratory distress, mechanical ventilation for 5 days or more, hyperbilirubinemia at levels that require exchange transfusion, bacterial meningitis, and use of ototoxic drugs.4-11 Given this uncertainty, we aimed to identify risk factors associated with HL in neonates.