RISK-FACTORS FOR CHILDHOOD SENSORINEURAL HEARING-LOSS IN THE OXFORD REGION

We have used a comprehensive register of hearing-impaired children bor n in the former Oxford Health Region to study risk factors for sensori neural hearing loss. The occurrence of a wide variety of risk factors was documented from the case notes of 145 children; these were all the cases known at the time of the study with all degrees of hearing loss born between 1984 and 1988. Comparison with the normal Regional popul ation showed that maternal age over 35 years and Asian ethnic origin w ere significant risk factors for congenital (non-acquired) hearing los s (odds ratio 1.7 and 2.5 respectively). Black/Asian children were als o significantly more likely to have acquired losses. Low birthweight ( below 2500 g) also gave a significantly increased risk, with an odds r atio of 4.5, rising to 9.6 for birthweight less than 1500 g. We also f ound that significantly more hearing-impaired cases were in lower soci al classes compared with the general population. A high proportion of cases (24%) had cranio-facial abnormalities (CFA), including many non- aural abnormalities and dysmorphic features, which therefore should be counted as high risk. Hearing losses acquired due to perinatal causes were almost all mild or moderate. Four factors - admission to special care baby unit for more than 72 hours, CFA, family history, and menin gitis - accounted for 69% of all cases in this study. Targeted neonata l screening based on the first three factors, plus obligatory testing following meningitis, therefore, should be highly efficient at detecti ng deafness early.