Abstract

Objective To investigate the risk for sensorineural hearing impairment (SNHI) in preterm infants, and to what extent the risk is attributed to perinatal morbidities and therapies. Design Population-based cohort study using data from several nationwide registries. Setting Norwegian birth cohort 1999–2014, with data on SNHI until 2019. Participants 60 023 live-born preterm infants, divided in moderate-late preterm (MLP) infants (32–36 weeks), very preterm (VP) infants (28–31 weeks) and extremely preterm (EP) infants (22–27 weeks), and a reference group with all 869 797 term-born infants from the study period. Main outcome measures SNHI defined by selected ICD-10 codes, recorded during minimum 5-year observation period after birth. Results The overall SNHI prevalence in the preterm cohort was 1.4% compared with 0.7% in the reference group. The adjusted risk ratios (95% CIs) for SNHI were 1.7 (1.5–1.8) in MLP infants, 3.3 (2.8–3.9) in VP infants and 7.6 (6.3–9.1) in EP infants. Among EP infants, decreasing gestational age was associated with a steep increase in the risk ratio of SNHI reaching 14.8 (7.7–28.7) if born at 22–23 weeks gestation. Among the VP and MLP infants, mechanical ventilation and antibiotic therapy had strongest association with increased risk of SNHI, but infants not receiving these therapies remained at increased risk. Among EP infants intracranial haemorrhage increased the already high risk for SNHI. We found no signs of delayed or late-onset SNHI in preterm infants. Conclusion Preterm birth is an independent risk factor for SNHI. Invasive therapies and comorbidities increase the risk, predominantly in infants born after 28 weeks gestation.