Better Hearing in Norway: A Comparison of Two HUNT Cohorts 20 Years Apart.
Bo Engdahl, Bjørn Heine Strand, Lisa Aarhus
PMID 32541261WHAT IT FOUND
Norwegian adults in 2017 had better hearing than those in 1996.
Disabling hearing loss dropped from 7.7% to 5.3%. Men aged 60 to 70 showed the biggest gain at high frequencies. This suggests occupational noise controls worked. Update your baseline expectations for hearing thresholds.
Key findings
01The prevalence of disabling hearing loss decreased from 7.7% in the earlier cohort to 5.3% in the recent cohort.
02Hearing thresholds were better in the more recent birth cohort at all frequencies for both men and women.
03The improvement was largest in men aged 60 to 70 at high frequencies, consistent with reduced occupational noise exposure.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
Response rates were lower in the recent survey (43%) compared to the earlier one (61%), raising the possibility of selection bias where healthier individuals participated. The study only looked at two time points, so it cannot show the pattern of change or when the improvement started. Audiometric equipment and procedures differed slightly between the two surveys, though researchers attempted to correct for this using reference populations. The sample under-represented very young and very old participants compared to the general population.
Declared interests
The authors have no conflicts of interest to disclose.
The easy way to misread this
Do not assume that hearing health is improving for all demographics equally or that future trends will continue. The study found mixed results for younger individuals in other literature, and the observed improvement in older adults is largely attributed to historical occupational noise regulations that may not apply to current younger cohorts facing different noise risks.