University of Manchester researchers have discovered that hearing loss may act as a cause of depression in older people.
And those in the lowest wealth groups, they found, had up to twice the relative risk of developing depression than those in the highest wealth quintiles, as hearing loss disproportionally affected their quality of life.
Published in Social Psychiatry and Psychiatric Epidemiology, the landmark study goes some way in laying to rest more than 40 years of research on whether hearing loss causes depression.
The data also showed that hearing aids have a stronger effect in alleviating symptoms of depression in poorer socio-economic groups than in wealthy ones.
And improved symptoms of depression were more pronounced among those using their hearing aids ‘most of the time’ than those using them ‘some of the time’.
The researchers analysed longitudinally the entire dataset of participants aged 50–89 years in 8 Waves of the English Longitudinal Study of Ageing (ELSA), from 2002 to 2017, examining 74,908 people.
The findings for the first time revealed that hearing loss affected people according to their socioeconomic position.
Dr Dalia Tsimpida, from The University of Manchester who led the study, said: “Our study shows that hearing loss poses a substantial risk for depressive symptoms in older adults, especially those who experience socioeconomic inequalities.
“We also think that hearing aids could support the most vulnerable people who already lacked life opportunities compared to the most affluent.
“That way they were able to take more control of their lives and keep participating actively in society.”
Dr Tsimpida, a Chartered Psychologist and postdoctoral researcher based in the University’s Division of Medical Education, added: “We think it’s reasonable to identify hearing loss as a causal factor because we used advanced statistical techniques called dynamic cross-lagged path models (CLPMs) to estimate hearing loss and depression’s relationship over time.
“We argue the early detection of hearing loss by primary care professionals in routine assessments may not only promote better hearing health but also prevent or delay the onset of depression.
“Increasing the hearing loss treatment rate could be one effective strategy for risk reduction of depression, given the high prevalence of hearing loss in older age and its low treatment levels.”
Co-author Dr Maria Panagioti said: “The existing evidence on the association between hearing loss and depression was conflicting; our study now adds to this body of knowledge by identifying for the first time the socioeconomic pattern in their relationship.”
“Focusing primarily on the role of the socioeconomic position may satisfactorily explain the causal, temporal and graded relationship between hearing loss and depression over time, which differs according to people’s status in the social hierarchy.
“Our study has important and novel clinical implications, as it adds to the understanding of the interrelationship between hearing loss and depression, and the potential impact of interventions with hearing aids for people’s mental health.”
Global estimates indicate that over 1.30 billion people currently live with some form of hearing loss and this prevalence will likely rise with the aging population (Wilson, Tucci, Merson, & O’Donoghue, 2017). For older adults (≥60 years of age), hearing loss is often caused by the loss of inner and outer hair cells at the basal end of the basilar membrane, which contributes to the loss of high frequency hearing and increased hearing thresholds experienced during aging (Peelle & Wingfield, 2016).
Approximately 13% of adults 40–49 years of age experience some form of hearing loss, whereas almost 45% of older adults aged 60–69 years live with hearing loss and this prevalence increases to 90% for adults 80 years and older (Goman & Lin, 2016). Aging may also be associated with increased risk of depression (Freeman et al., 2016), which is characterized by sadness, feelings of low self-worth or guilt, a loss of interest in daily activities, and disturbed appetite or sleep, which affect concentration (World Health Organization, 2018).
Approximately 15% of older adults experience mild depressive symptoms and 1%–5% live with major depressive disorder (Fiske, Wetherell, & Gatz, 2009). Moreover, research has shown an association between hearing loss and depression in older adults (e.g., Keidser & Seeto, 2017; Rosso et al., 2013), with age-related changes in psychosocial experience as well as degeneration to cortical activity proposed to explain these concomitant conditions.
The association between hearing loss and depression in older adults has most frequently been examined within, and explained by, the potential influence of psychosocial changes experienced during aging. Kiely, Anstey, and Luszcz (2013) initially found that severity of depressive symptoms was associated with hearing loss in older adults, but this association reduced to nonsignificance (i.e., was accounted for) when difficulty completing daily activities and degree of social engagement in daily life were included in the model. Further evidence shows a faster decline in hearing is associated with greater social and emotional loneliness among older adults (Pronk et al., 2014), and when left untreated, hearing loss may develop into a chronic stressor that leads to the proliferation of depression as an additional stressor (West, 2017).
Hearing loss may therefore worsen existing difficulties associated with psychosocial and functional abilities during older age, increasing the likelihood of developing depression. Conversely, recent evidence shows no influence of psychosocial factors (i.e., less participation in social activities or access to a social network) on the association between hearing loss and depression in older adults (Cosh et al., 2018).
The authors proposed that older adults may accept hearing loss as part of the normal aging experience and therefore adapt to changes in their hearing by modifying/improving their communication skills or using hearing aids to alleviate the burden of hearing loss, which in turn mitigates the potential negative impact of hearing loss on psychosocial experiences that may precede depression (Cosh et al., 2018).
It is therefore not clear if the association between hearing loss and depression in older adults can be explained by a psychosocial mechanism in later life. A meta-analysis and systematic review of the literature will provide an estimate of this comorbid association and the potential influence of psychosocial or health characteristics that may account for this relationship in older adults.
Recent evidence also suggests that degeneration to neuropathological mechanisms associated with auditory perception and regulation of mood may explain the relationship between hearing loss and depression in older adults. As extensively reviewed by Rutherford, Brewster, Golub, Kim, and Roose (2018), neuroimaging studies show similar patterns of diminished activity in the limbic system (responsible for emotion and behavior), the frontal cortex (responsible for emotional regulation, reasoning, and planning), and auditory cortex in older adults with hearing loss or depression.
These initial findings suggest the presence of common neural degeneration associated with hearing loss and depression in older adults, but more evidence is needed to increase our understanding of the pathophysiology underlying hearing loss and depression in later life.
To date, the association between hearing loss and depression is most frequently reported in epidemiological studies. Some cross-sectional studies report an association between hearing loss and depression during older age (Behera et al., 2016; Keidser & Seeto, 2017; Lee & Hong, 2016), whereas others report no relationship (Bergdahl et al., 2005; Chou & Chi, 2005). Similar evidence exists for cohort studies, with initial results showing hearing loss is associated with increased odds of depression among older adults (Forsell, 2000) and later studies repudiating these findings (Chou, 2008; (Cosh et al., 2018).
Conflicting findings in the literature may be the consequence of methodological variance between studies and the limitations associated with epidemiological research. As a method of investigation, epidemiology allows for the examination of health characteristics within large population-based samples of participants when conducting a more controlled clinical trial is not feasible (e.g., examining intercontinental dietary patterns) or ethical (e.g., examining the health effects of smoking).
However, epidemiological studies are often influenced by biases that undermine reliability in their results. As reported by Ioannidis (2016), most initial statistically significant epidemiological findings are later not replicated in more scientifically robust randomized controlled trials. Moreover, large longitudinal epidemiological studies examining changes in health characteristics (e.g., U.S. National Health and Nutrition Epidemiological Survey) often find statistically significant correlations between almost all variables of interest (Patel, Ioannidis, Cullen, & Rehkopf, 2015).
With these limitations in mind, however, a meta-analysis and systematic review of epidemiological (e.g., cross-sectional and cohort) studies can provide a more rigorous estimate of an association between health characteristics (e.g., hearing loss and depression), while drawing attention to the strengths and weaknesses within the existing evidence and providing recommendations for future clinical practice.
Previous studies investigating the association between hearing loss and depression have estimated hearing loss using objective measures such as pure tone audiometry (Hidalgo et al., 2009; Kiely et al., 2013), but a proportion of studies only report subjective hearing loss measured by self-report outcomes (e.g., Boorsma et al., 2012; Saito et al., 2010). Some of these studies included a proportion of participants with cognitive decline (Perlmutter, Bhorade, Gordon, Hollingsworth, & Baum, 2010). Described as deficits in cognitive function not normal for age and level of education, cognitive decline in older adults may range from mild cognitive impairment to dementia (Albert et al., 2011).
Increasing evidence shows an association between hearing loss and cognitive decline in older adults (Loughrey, Kelly, Kelley, Brennan, & Lawlor, 2017), and a decline in cognitive function has been associated with depression (Wang & Blazer, 2015). We may therefore expect a stronger association between hearing loss and depression in older adults that also demonstrate presence of cognitive decline (Rutherford et al., 2018). Participant experience using hearing aids also varies across studies (Chou, 2008; Pronk et al., 2011; Rosso et al., 2013).
Hearing aids may alleviate depressive symptoms associated with hearing loss in older adults (Choi et al., 2016; Manrique-Huarte, Calavia, Irujo, Girón, & Manrique-Rodríguez, 2016), which may influence the association between hearing loss and depression in observational research. In addition, a high proportion of studies do not report outcome results adjusted for the confounding influence of covariates (e.g., health/psychosocial characteristics), which undermines validity of their findings (Al Sabahi, Al Sinawi, Al Hinai, & Youssef, 2014; Chou & Chi, 2005; Hidalgo et al., 2009).
It is also well-understood that cross-sectional studies cannot infer causality and are therefore unable to determine if there is temporal relationship between hearing loss and depression. Initial meta-analytic evidence from a small number of studies showed an association between hearing loss and depression in later life (Huang, Dong, Lu, Yue, & Liu, 2010), but more studies have since been published and inconsistency in the findings warrants the need for a systematic review and meta-analysis of the evidence.
The primary aim of this systematic review and meta-analysis was to synthesize the available evidence to provide a summary effect estimate of the association between hearing loss and depression in older adults. The secondary aim was to examine whether study (e.g., design, outcome measures) or participant (e.g., demographic, health) characteristics may influence the association between hearing loss and depression.
An extensive systematic review of the literature was conducted and all available evidence was included in this study to provide the most rigorous estimate of the association between hearing loss and depression in older adults.
reference link : https://academic.oup.com/gerontologist/article/60/3/e137/5369884?login=true
“The dynamic relationship between hearing loss, quality of life, socioeconomic position and depression and the impact of hearing aids: answers from the English Longitudinal Study of Ageing (ELSA)” by Dalia Tsimpida et al. Social Psychiatry and Psychiatric Epidemiology