Objective: The objective of this study was to determine the role of non-hospital delivery and other risk factors for permanent congenital and early-onset hearing loss (PCEHL) in a developing country.
Design: Matched case-control study.
Setting: Four primary healthcare centres in inner-city Lagos, Nigeria.
Population: Fifty-six infants with PCEHL and 280 normal hearing controls matched for age and sex from a population of infants not older than 3 months attending Bacille de Calmette-Guérin immunisation clinics.
Methods: Conditional logistic regression analyses of infant and maternal characteristics associated with PCEHL, and the evaluation of population exposure to each risk factor.
Main outcome measures: Adjusted matched odds ratios and population attributable risk percent (PAR%).
Results: Children with PCEHL were significantly more likely to be first born (OR 1.9, 95% CI 1.1-3.6) without skilled attendants at birth (OR 2.4, 95% CI 1.3-4.5) and have a history of neonatal jaundice requiring exchange blood transfusion (NNJ/EBT) (OR 9.6, 95% CI 2.4-38.2) but less likely to be small for gestational age (SGA) (OR 0.1, 95% CI 0.0-0.5). After controlling for other covariates, the absence of skilled attendants at birth (OR 4.2, 95% CI 2.0-8.6) and NNJ/EBT (OR 19.1, 95% CI 4.3-85.5) emerged as predictors of PCEHL, while SGA (OR 0.1, 95% CI 0.0-0.2) retained its inverse relationship with PCEHL. The PAR% was 35.9% for the lack of skilled attendants at birth and 10.6% for having NNJ/EBT. About 23% of children with PCEHL did not exhibit any risk factors.
Conclusions: NNJ/EBT and the absence of skilled attendant at birth rather than the place of delivery are significant predictors of PCEHL in this study population. Targeted hearing screening using these risk factors would facilitate the detection of about 77% of children with PCEHL.