Global and regional hearing impairment prevalence: an analysis of 42 studies in 29 countries
TL;DR: The results suggest that the prevalence of child and adult hearing impairment is substantially higher in middle- and low- income countries than in high-income countries, demonstrating the global need for attention to hearing impairment.
Abstract: Background: Hearing impairment is a leading cause of disease burden, yet population-based studies that measure hearing impairment are rare. We estimate regional and global hearing impairment prevalence from sparse data and calculate corresponding uncertainty intervals. Methods: We accessed papers from a published literature review and obtained additional detailed data tabulations from investigators. We estimated the prevalence of hearing impairment by region, sex, age and hearing level using a Bayesian hierarchical model, a method that is effective for sparse data. As the primary objective of modelling was to produce regional and global prevalence estimates, including for those regions with scarce to no data, models were evaluated using cross-validation. Results: We used data from 42 studies, carried out between 1973 and 2010 in 29 countries. Hearing impairment was positively related to age, male sex and middle- and low-income regions. We estimated that the global prevalence of hearing impairment (defined as an average hearing level of 35 decibels or more in the better ear) in 2008 was 1.4% (95% uncertainty interval 1.0–2.2%) for children aged 5–14 years, 9.8% (7.7–13.2%) for females >15 years of age and 12.2% (9.7–16.2%) for males >15 years of age. The model exhibited good external validity in the cross-validation analysis, with 87% of survey estimates falling within our final model's 95% uncertainty intervals. Conclusion: Our results suggest that the prevalence of child and adult hearing impairment is substantially higher in middle- and low-income countries than in high-income countries, demonstrating the global need for attention to hearing impairment.
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TL;DR: Hearing loss is independently associated with accelerated cognitive decline and incident cognitive impairment in community-dwelling older adults and the mechanistic basis of this association is and whether hearing rehabilitative interventions could affect cognitive decline is investigated.
Abstract: Background:Whetherhearinglossisindependentlyassociatedwithacceleratedcognitivedeclineinolderadults is unknown. Methods:Westudied1984olderadults(meanage,77.4 years) enrolled in the Health ABC Study, a prospective observational study begun in 1997-1998. Our baseline cohort consisted of participants without prevalent cognitive impairment (Modified Mini-Mental State Examination [3MS] score, 80) who underwent audiometric testinginyear5.Participantswerefollowedupfor6years. Hearing was defined at baseline using a pure-tone average of thresholds at 0.5 to 4 kHz in the better-hearing ear. Cognitive testing was performed in years 5, 8, 10, and11andconsistedofthe3MS(measuringglobalfunction) and the Digit Symbol Substitution test (measuring executive function). Incident cognitive impairment was definedasa3MSscoreoflessthan80oradeclinein3MS score of more than 5 points from baseline. Mixedeffects regression and Cox proportional hazards regression models were adjusted for demographic and cardiovascular risk factors. Results: In total, 1162 individuals with baseline hearing loss (pure-tone average 25 dB) had annual rates of declinein3MSandDigitSymbolSubstitutiontestscoresthat were41%and32%greater,respectively,thanthoseamong individuals with normal hearing. On the 3MS, the annual score changes were 0.65 (95% CI, 0.73 to 0.56) vs 0.46(95%CI,0.55to0.36)pointsperyear(P=.004). On the Digit Symbol Substitution test, the annual score changes were 0.83 (95% CI, 0.94 to 0.73) vs 0.63 (95% CI, 0.75 to 0.51) points per year (P=.02). Comparedtothosewithnormalhearing,individualswithhearing loss at baseline had a 24% (hazard ratio, 1.24; 95% CI, 1.05-1.48) increased risk for incident cognitive impairment. Rates of cognitive decline and the risk for incident cognitiveimpairmentwerelinearlyassociatedwiththeseverity of an individual’s baseline hearing loss.
1,223 citations
TL;DR: The traditional concept and grades of disabling hearing impairment are examined - within the context of the International Classification of Functioning, Disability and Health - as well as the modifications to grading that have recently been proposed by a panel of international experts.
Abstract: At any age, disabling hearing impairment has a profound impact on interpersonal communication, psychosocial well-being, quality of life and economic independence. According to the World Health Organization’s estimates, the number of people with such impairment increased from 42 million in 1985 to about 360 million in 2011. This last figure includes 7.5 million children less than 5 years of age. In 1995, a “roadmap” for curtailing the burden posed by disabling hearing impairment was outlined in a resolution of the World Health Assembly. While the underlying principle of this roadmap remains valid and relevant, some updating is required to reflect the prevailing epidemiologic transition. We examine the traditional concept and grades of disabling hearing impairment – within the context of the International Classification of Functioning, Disability and Health – as well as the modifications to grading that have recently been proposed by a panel of international experts. The opportunity offered by the emerging global and high-level interest in promoting disability-inclusive post-2015 development goals and disability-free child survival is also discussed. Since the costs of rehabilitative services are so high as to be prohibitive in low- and middle-income countries, the critical role of primary prevention is emphasized. If the goals outlined in the World Health Assembly’s 1995 resolution on the prevention of hearing impairment are to be reached by Member States, several effective country-level initiatives – including the development of public–private partnerships, strong leadership and measurable time-bound targets – will have to be implemented without further delay.
404 citations
TL;DR: The burden of hearing loss is described and recommendations for halting and then reversing the continuing increases in this burden are offered, as well as low-cost possibilities for prevention and unprecedented opportunities to reduce the generally high treatment costs.
352 citations
TL;DR: Self-reported HI and audiometrically determined HI were significantly associated with depression, particularly in women, and health care professionals should be aware of an increased risk for depression among adults with hearing loss.
Abstract: Importance Depression among hearing impaired US adults has not been studied previously. Objective To estimate the prevalence of and risk factors for depression among adults with hearing loss. Design, Setting, and Participants Adults aged 18 years or older (N = 18 318) who participated in the National Health and Nutrition Examination Survey (NHANES), 2005-2010, a nationally representative sample. Interventions Multistage probability sampling of US population. Main Outcomes and Measures Depression, assessed by the 9-item Patient Health Questionnaire (PHQ-9) scale, and hearing impairment (HI), assessed by self-report and audiometric examination for adults aged 70 years or older. Results The prevalence of moderate to severe depression (PHQ-9 score, ≥10) was 4.9% for individuals reporting excellent hearing, 7.1% for those with good hearing, and 11.4% for participants who reported a little trouble or greater HI. Using excellent hearing as the reference, after adjusting for all covariates, multivariate odds ratios (ORs) for depression were 1.4 (95% CI, 1.1-1.8) for good hearing, 1.7 (1.3-2.2) for a little trouble, 2.4 (1.7-3.2) for moderate trouble, 1.5 (0.9-2.6) for a lot of trouble, and 0.6 (0.1-2.6) for deaf. Moderate HI (defined by better ear pure-tone average of hearing thresholds at 0.5, 1, 2, and 4 kHz within the range 35- to 49-dB hearing level) was significantly associated with depression among older women (OR, 3.9; 95% CI, 1.3-11.3), after adjusting for age, sex, race/ethnicity, lifestyle characteristics, and selected health conditions. Conclusions and Relevance After accounting for health conditions and other factors, including trouble seeing, self-reported HI and audiometrically determined HI were significantly associated with depression, particularly in women. Health care professionals should be aware of an increased risk for depression among adults with hearing loss.
274 citations
TL;DR: Novel studies confirm the involvement of peripheral de Afferentation for tinnitus and hyperacusis, but suggest that the disorder results from different brain responses to different degrees of deafferentation: while tinnitis may arise as a failure of the brain to adapt to deprived peripheral input, hyperacusIS may result from an 'over-adaptive' increase in response gain.
257 citations
Cites background from "Global and regional hearing impairm..."
...Forty-two previous reports published between 1973 and 2010 in 29 countries have revealed increased hearing loss with age; developing countries report higher rates of moderate and moderately-severe hearing impairment due to higher rates of pre- and postnatal childhood infections such as rubella, measles and meningitis, and from the use of ototoxic drugs (Stevens et al., 2013)....
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...…revealed increased hearing loss with age; developing countries report higher rates of moderate and moderately-severe hearing impairment due to higher rates of pre- and postnatal childhood infections such as rubella, measles and meningitis, and from the use of ototoxic drugs (Stevens et al., 2013)....
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01 Jan 2006TL;DR: Data Analysis Using Regression and Multilevel/Hierarchical Models is a comprehensive manual for the applied researcher who wants to perform data analysis using linear and nonlinear regression and multilevel models.
Abstract: Data Analysis Using Regression and Multilevel/Hierarchical Models is a comprehensive manual for the applied researcher who wants to perform data analysis using linear and nonlinear regression and multilevel models. The book introduces a wide variety of models, whilst at the same time instructing the reader in how to fit these models using available software packages. The book illustrates the concepts by working through scores of real data examples that have arisen from the authors' own applied research, with programming codes provided for each one. Topics covered include causal inference, including regression, poststratification, matching, regression discontinuity, and instrumental variables, as well as multilevel logistic regression and missing-data imputation. Practical tips regarding building, fitting, and understanding are provided throughout.
9,098 citations
01 Jan 2000
TL;DR: The World Health Organization (WHO) adopted a standard based on the average age-structure of those populations to be compared (the world) over the likely period of time that a new standard will be used (some 25-30 years), using the latest UN assessment for 1998 (UN Population Division, 1998) from these estimates, an average world population agestructure was constructed for the period 2000-2025 as discussed by the authors.
Abstract: Summary A recent WHO analysis has revealed the need for a new world standard population (see attached table). This has become particularly pertinent given the rapid and continued declines in age-specific mortality rates among the oldest old, and the increasing availability of epidemiological data for higher age groups. There is clearly no conceptual justification for choosing one standard over another, hence the choice is arbitrary. However, choosing a standard population with higher proportions in the younger age groups tends to weight events at these ages disproportionately. Similarly, choosing an older standard does the opposite. Hence, rather than selecting a standard to match the current age-structure of some population(s), the WHO adopted a standard based on the average age-structure of those populations to be compared (the world) over the likely period of time that a new standard will be used (some 25-30 years), using the latest UN assessment for 1998 (UN Population Division, 1998). From these estimates, an average world population age-structure was constructed for the period 2000-2025. The use of an average world population, as well as a time series of observations, removes the effects of historical events such as wars and famine on population age composition. The terminal age group in the new WHO standard population has been extended out to 100 years and over, rather than the 85 and over as is the current practice. The WHO World Standard population has fewer children and notably more adults aged 70 and above than the world standard. It is also notably younger than the European standard. It is important to note, however, that the age standardized death rates based on the new standard are not comparable to previous estimates that are based on some earlier standard(s). However, to facilitate comparative analyses, WHO will disseminate trend analyses of the “complete” historical mortality data using on the new WHO World Standard Population in future editions of the World Health Statistics Annual.
2,065 citations
01 Jan 2002
TL;DR: The World Health Organization (WHO) adopted a standard based on the average age-structure of those populations to be compared (the world) over the likely period of time that a new standard will be used (some 25-30 years), using the latest UN assessment for 1998 (UN Population Division, 1998) from these estimates, an average world population agestructure was constructed for the period 2000-2025 as mentioned in this paper.
Abstract: Summary A recent WHO analysis has revealed the need for a new world standard population (see attached table). This has become particularly pertinent given the rapid and continued declines in age-specific mortality rates among the oldest old, and the increasing availability of epidemiological data for higher age groups. There is clearly no conceptual justification for choosing one standard over another, hence the choice is arbitrary. However, choosing a standard population with higher proportions in the younger age groups tends to weight events at these ages disproportionately. Similarly, choosing an older standard does the opposite. Hence, rather than selecting a standard to match the current age-structure of some population(s), the WHO adopted a standard based on the average age-structure of those populations to be compared (the world) over the likely period of time that a new standard will be used (some 25-30 years), using the latest UN assessment for 1998 (UN Population Division, 1998). From these estimates, an average world population age-structure was constructed for the period 2000-2025. The use of an average world population, as well as a time series of observations, removes the effects of historical events such as wars and famine on population age composition. The terminal age group in the new WHO standard population has been extended out to 100 years and over, rather than the 85 and over as is the current practice. The WHO World Standard population has fewer children and notably more adults aged 70 and above than the world standard. It is also notably younger than the European standard. It is important to note, however, that the age standardized death rates based on the new standard are not comparable to previous estimates that are based on some earlier standard(s). However, to facilitate comparative analyses, WHO will disseminate trend analyses of the “complete” historical mortality data using on the new WHO World Standard Population in future editions of the World Health Statistics Annual.
736 citations
TL;DR: PyMC as discussed by the authors is a Python package that allows users to efficiently code a probabilistic model and draw samples from its posterior distribution using Markov chain Monte Carlo techniques using a user guide.
Abstract: This user guide describes a Python package, PyMC, that allows users to efficiently code a probabilistic model and draw samples from its posterior distribution using Markov chain Monte Carlo techniques.
602 citations
TL;DR: There is evidence to suggest that statin therapy is associated with a statistically significant reduction in the risk of primary and secondary cardiovascular events and there is limited evidence for the effectiveness of statins in different subgroups.
Abstract: Objectives To evaluate the clinical effectiveness and cost-effectiveness of statins for the primary and secondary prevention of cardiovascular events in adults with, or at risk of, coronary heart disease (CHD). Data sources Electronic databases were searched between November 2003 and April 2004. Review methods A review was undertaken to identify and evaluate all literature relating to the clinical and cost effectiveness of statins in the primary and secondary prevention of CHD and cardiovascular disease (CVD) in the UK. A Markov model was developed to explore the costs and health outcomes associated with a lifetime of statin treatment using a UK NHS perspective. Results Thirty-one randomised studies were identified that compared a statin with placebo or with another statin, and reported clinical outcomes. Meta-analysis of the available data from the placebo-controlled studies indicates that, in patients with, or at risk of, CVD, statin therapy is associated with a reduced relative risk of all cause mortality, cardiovascular mortality, CHD mortality and fatal myocardial infarction (MI), but not of fatal stroke. It is also associated with a reduced relative risk of morbidity [non-fatal stroke, non-fatal MI, transient ischaemic attack (TIA), unstable angina] and of coronary revascularisation. It is hardly possible, on the evidence available from the placebo-controlled trials, to differentiate between the clinical efficacy of atorvastatin, fluvastatin, pravastatin and simvastatin. However, there is some evidence from direct comparisons between statins to suggest that atorvastatin may be more effective than pravastatin in patients with symptomatic CHD. There is limited evidence for the effectiveness of statins in different subgroups. Statins are generally considered to be well tolerated and to have a good safety profile. This view is generally supported both by the evidence of the trials included in this review and by postmarketing surveillance data. Increases in creatine kinase and myopathy have been reported, but rhabdomyolysis and hepatotoxicity are rare. However, some patients may receive lipid-lowering therapy for as long as 50 years, and long-term safety over such a timespan remains unknown. In secondary prevention of CHD, the incremental cost-effectiveness ratios (ICERs) increase with age varying between pound 10,000 and pound 17,000 per quality adjusted life year (QALY) for ages 45 and 85 respectively. Sensitivity analyses show these results are robust. In primary prevention of CHD there is substantial variation in ICERs by age and risk. The average ICERs weighted by risk range from pound 20,000 to pound 27,500 for men and from pound 21,000 to pound 57,000 for women. The results are sensitive to the cost of statins, discount rates and the modelling time frame. In the CVD analyses, which take into account the benefits of statins on reductions in stroke and TIA events, the average ICER weighted by risk level remains below pound 20,000 at CHD risk levels down to 0.5%. Limitations of the analyses include the requirement to extrapolate well beyond the timeframe of the trial period, and to extrapolate effectiveness results from higher risk primary prevention populations to the treatment of populations at much lower risk. Consequently, the results for the lower age bands and lower risks are subject to greater uncertainty and need to be treated with caution. Conclusions There is evidence to suggest that statin therapy is associated with a statistically significant reduction in the risk of primary and secondary cardiovascular events. As the confidence intervals for each outcome in each prevention category overlap, it is not possible to differentiate, in terms of relative risk, between the effectiveness of statins in primary and secondary prevention. However, the absolute risk of CHD death/non-fatal MI is higher, and the number needed to treat to avoid such an event is consequently lower, in secondary than in primary prevention. The generalisability of these results is limited by the exclusion, in some studies, of patients who were hypersensitive to, intolerant of, or known to be unresponsive to, statins, or who were not adequately compliant with study medication during a placebo run-in phase. Consequently, the treatment effect may be reduced when statins are used in an unselected population. The results of the economic modelling show that statin therapy in secondary prevention is likely to be considered cost-effective. In primary prevention, the cost-effectiveness ratios are dependent on the level of CHD risk and age, but the results for the CVD analyses offer support for the more aggressive treatment recommendation issued by recent guidelines in UK. Evidence on clinical endpoints for rosuvastatin is awaited from on-going trials. The potential targeting of statins at low-risk populations is however associated with major uncertainties, particularly the likely uptake and long-term compliance to lifelong medication by asymptomatic younger patients. The targeting, assessment and monitoring of low-risk patients in primary care would be a major resource implication for the NHS. These areas require further research.
571 citations