Population study of hearing disorders in adults: preliminary communication.

The Institute of Hearing Research is embarked upon a study of the prevalence, characteristics and determinants of hearing problems and tinnitus in the adult population of the UK. One of its objectives is to ascertain the size of the problem in terms both of numbers of people affected and the degrees to which they are affected. Such knowledge is highly relevant to any consideration of the services needed for the adult hearing impaired. The overall plan for the study and the results of its pilot study are outlined. In Tier A, a questionnaire on hearing difficulties and tinnitus was sent to 6804 persons living in Cardiff, Glasgow, Nottingham and Southampton. This enabled stratification of respondents by age groups and reported impairments, and thereby permitted appropriate sampling ratios from those strata to be invited to attend the clinics for the Tier B clinical and audiological investigations. Response rates were around 80% at Tier A and 50% at Tier B; domiciliary follow up showed the biases in non-responders and non-attenders to be minimal. About 25% of the sample reported some hearing difficulty, and about 17% reported an experience of tinnitus that was more than transitory or temporary noise-induced. Taking a criterion of over 25 dB hearing level in the better ear, averaged across 0.5, 1, 2 and 4 kHz, a prevalence estimate for the UK population is that 19.9 +/- 4.4% of adults are so affected. About 0.5-1% of adults appear to be severely affected by tinnitus; this amounts to about 200 000 persons in the UK. The scale of the problem has not been fully appreciated before and points to an urgent need to develop further the clinical services and research effort in the field of tinnitus.