Abstract:
BACKGROUND AND OBJECTIVES : Substantial evidence supports the association between untreated hearing loss, cognitive decline, and dementia
in the non-tonal language-speaking population. Whether a similar association between hearing loss and cognitive decline and dementia exists
in Sinitic tonal language-speaking people is yet to be elucidated. We aimed to systematically review the current evidence on the association
between hearing loss and cognitive impairment/decline, and dementia in older adults who speak a Sinitic tonal language.
RESEARCH DESIGN AND METHODS : This systematic review considered peer-reviewed articles that employed objective or subjective hearing measurement
and cognitive function, cognitive impairment, or diagnosis of dementia. All articles written in English and Chinese and published before
March 2022 were included. Databases including Embase, MEDLINE, Web of Science, PsycINFO and Google Scholar, SinoMed, and CBM were
utilized using MeSH terms and keywords.
RESULTS : Thirty-five articles met our inclusion criteria. Of these, 29 unique studies with an estimated 372,154 participants were included in the
meta-analyses. Among all included studies, the effect size of cognitive function with hearing loss, the regression coefficient was −0.26 (95%
confidence interval [CI], −0.45 to −0.07). Among cross-sectional and cohort studies, a significant association was found between hearing loss
and cognitive impairment and dementia, with odds ratios of 1.85 (95% CI, 1.59–2.17) and 1.89 (95% CI, 1.50–2.38), respectively.
DISCUSSION AND IMPLICATIONS : Most of the studies included in this systematic review observed a significant association between hearing loss
and cognitive impairment and dementia. There was no significant difference to the findings in non-tonal language populations.
