Hearing loss associated with ear infections in Nord-Trøndelag, Norway.
OBJECTIVE
We have assessed the effect of recurrent childhood ear infections on adult hearing. We also examined whether adult hearing is poorer with an early age of onset of ear infections compared with later onset.


METHODS
A population-based cohort of 50,398 subjects, 20 yr of age or older, were examined with air-conduction, pure-tone audiometry and reported if they had had recurrent ear infections (EI) in childhood (or subsequently) with the age of onset.


RESULTS
There were poorer hearing thresholds associated with recurrent EI for all frequency ranges from 0.25 kHz to 8 kHz, regardless of age or gender. The effect increased with age from approximately 2 dB among younger subjects (20 to 44 yr old) to approximately 5 to 6 dB among older subjects (65 yr or older). Among younger subjects, the effect of EI was somewhat stronger for men, whereas among older subjects the effect was somewhat stronger for women. Early age of onset for EI was associated with poorer hearing thresholds than late onset. The mean loss was close to 9 to 10 dB for all frequency ranges among older subjects reporting onset of EI before 2 yr of age. The mean loss was only about 4 dB among older subjects reporting onset of EI after 7 yr of age.


CONCLUSIONS
Reported EIs are associated with similar consequences in terms of reduced hearing across frequencies 0.25 to 8 kHz for male and female subjects. The observed effects are stronger among older than among younger subjects, perhaps because effects increase with age or possibly because EI affected the hearing more before 1940 than during subsequent decades. Reported early age of onset of EI increases the risk of a substantially reduced hearing level later in life.
Tambs
Kristian
K
Epidemiology Section, Norwegian Institute of Public Health, N-0403 Oslo, Norway. kristian.tambs@fhi.no
Hoffman
Howard J
HJ
Engdahl
Bo
B
Borchgrevink
Hans M
HM
D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D000368:Aged; D000704:Analysis of Variance; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D006314:Hearing Loss, Conductive / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D010033:Otitis Media / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology; D015995:Prevalence; D012008:Recurrence; D011795:Surveys and Questionnaires