Hearing Loss and Depression in Older Adults: A Small Association

We read the article by Lisan et al,1Lisan Q van Sloten TT Lemogne C et al.Association of hearing impairment with incident depressive symptoms: a community-based prospective study.Am J Med. 2019; 132: 1441-1449.e4Abstract Full Text Full Text PDF Scopus (10) Google Scholar which examined the association between hearing impairment and depression in older adults, as well as the recent letter by Kawada,2Kawada T Hearing impairment and depressive symptoms: a risk assessment.Am J Med. 2020; 133 (e382)Abstract Full Text Full Text PDF Scopus (1) Google Scholar which highlighted 2 concerns with the study and referenced our systematic review and meta-analysis examining the association between hearing loss and depression.3Lawrence BJ Jayakody DMP Bennett RJ Eikelboom RH Gasson N Friedland PL Hearing loss and depression in older adults: a systematic review and meta-analysis.Gerontologist. 2019; 60: e137-e154Crossref Scopus (52) Google Scholar We agree with Kawada's2Kawada T Hearing impairment and depressive symptoms: a risk assessment.Am J Med. 2020; 133 (e382)Abstract Full Text Full Text PDF Scopus (1) Google Scholar concerns that several age-related factors likely affect the relationship between hearing loss and depression in older adults and, based upon the existing evidence, it is not clear whether there is a dose-response relationship between hearing loss and depression. However, there is an important finding not acknowledged in the literature but common to almost all studies examining the association between depression and hearing loss: the size of the association is very small. Our systematic review and meta-analysis examining hearing loss and depression in older adults included 35 studies and more than 140,000 participants.3Lawrence BJ Jayakody DMP Bennett RJ Eikelboom RH Gasson N Friedland PL Hearing loss and depression in older adults: a systematic review and meta-analysis.Gerontologist. 2019; 60: e137-e154Crossref Scopus (52) Google Scholar The overall pooled odds ratio for the association between hearing loss and depression was 1.47 (95% confidence interval, 1.31-1.65). In accordance with recommended conventions,4Chen H Cohen P Chen S How big is a big odds ratio? Interpreting the magnitudes of odds ratios in epidemiological studies.Commun Stat Simul Comput. 2010; 39: 860-864Crossref Scopus (622) Google Scholar an odds ratio of 1.68 is small, 3.47 is medium, and 6.71 is large. The size of the association found in our meta-analysis is therefore classified as a very small effect. Lisan et al's recent study1Lisan Q van Sloten TT Lemogne C et al.Association of hearing impairment with incident depressive symptoms: a community-based prospective study.Am J Med. 2019; 132: 1441-1449.e4Abstract Full Text Full Text PDF Scopus (10) Google Scholar also found a very small effect, with an odds ratio of 1.36 (95% confidence interval, 1.06-1.73) for the association between hearing loss and depression. It is therefore increasingly clear that the association between hearing loss and depression in older adults is very small, which suggests that only a (very) small proportion of older adults with hearing loss are likely to experience depressive symptoms directly associated with hearing deficits. Conversely, many older adults with hearing loss will also likely experience comorbidities (eg, cognitive decline, social isolation, loneliness) that are more strongly associated with an increased risk of depression in later life.5Taylor WD. Depression in the elderly.N Engl J Med. 2014; 371: 1228-1236Crossref PubMed Scopus (159) Google Scholar Despite the consistently small associations between hearing loss and depression, almost all epidemiological studies examining this relationship fail to interpret their effect sizes with caution and instead focus on the statistical significance of the associations. It is important to emphasize that, even if a study finds a statistically significant association between outcomes (eg, hearing loss and depression), the size of that association must be reported with caution to ensure it is not misinterpreted by the broader scientific community, as well as health care professionals (ie, audiologists) who rely on this evidence to inform decision-making in practice. For example, epidemiological studies frequently report statistically significant odds ratios as a percentage (eg, an odds ratio of 1.36 as a 36% increase in odds of depression). Although this is an accurate interpretation of this statistic, without a thorough understanding of these statistical tools and broader epidemiological research practices, many researchers and health care professionals will misinterpret 36% (for example) as representative of a large effect that requires urgent attention. As noted above, however, most studies examining the association between hearing loss and depression continue to find effects that are classified as small to very small, despite often reporting them as statistically significant percentages that likely lead to an inflated misinterpretation of their impact on the lives of older adults living with hearing loss. The findings from our systematic review and meta-analysis showed that hearing loss is associated with a very small increase in the odds of depression in older adults,3Lawrence BJ Jayakody DMP Bennett RJ Eikelboom RH Gasson N Friedland PL Hearing loss and depression in older adults: a systematic review and meta-analysis.Gerontologist. 2019; 60: e137-e154Crossref Scopus (52) Google Scholar and this finding has been supported by a very small odds ratio also reported in the recent study by Lisan et al.1Lisan Q van Sloten TT Lemogne C et al.Association of hearing impairment with incident depressive symptoms: a community-based prospective study.Am J Med. 2019; 132: 1441-1449.e4Abstract Full Text Full Text PDF Scopus (10) Google Scholar We therefore recommend that future researchers exploring the association between hearing loss, depression, and other psychosocial factors that likely influence this relationship provide a more cautious interpretation of their findings and relevant effect sizes to ensure greater transparency in how we communicate our research to health care professionals and the broader scientific community.