Introduction

Hearing loss (HL) is a major and growing public health concern, particularly among aging populations. According to the World Health Organization (WHO), over 1.5 billion people globally are affected by some degree of hearing impairment1, with prevalence rising sharply after the age of 402. As global life expectancy continues to rise and populations age3, HL is projected to become one of the leading contributors to disability among older adults.

In addition to its direct impact, HL frequently coexists with several chronic conditions, including cardiovascular disease (CVD), diabetes, stroke, and depression. These diseases were selected for this study due to their strong epidemiological and pathophysiological links to HL. Shared mechanisms between these chronic diseases and HL include vascular dysfunction, inflammation, and metabolic dysregulation4,5,6,7, which may accelerate disability, cognitive decline, and social isolation, especially in older adults. These interconnections make HL an important factor in the overall burden of multimorbidity.

The relationship between HL and these chronic conditions is complex and likely bidirectional. For instance, diabetes is associated with microvascular damage, which can impair cochlear function5, while stroke can lead to damage of the auditory pathways in the brain8. Although the relationship between CVD and HL is recognized, it is less well understood. The effects of poor circulation caused by CVD may contribute to auditory impairments, although this link has not always been consistently observed in studies. Furthermore, HL and depression are known to be strongly linked, with HL contributing to social isolation, cognitive decline, and reduced quality of life, all of which are well-established risk factors for depression9,10,11,12.

While existing research has highlighted the associations between HL and chronic conditions, there remains a lack of comprehensive studies that explore the global patterns of HL and its comorbidity with chronic diseases. Most studies have been limited to single-country analyses9,13,14, which makes it difficult to generalize findings on a global scale. This study aims to address this gap by analyzing the global burden of HL and its comorbidity with diabetes, CVD, stroke, and depression using data from the Global Burden of Disease (GBD) 2021 study. The study focuses on individuals aged 45 and older and examines trends from 1990 to 2021 across different regions, age groups, and sexes.

Our analysis is framed within the Healthy Aging Framework developed by the WHO15, which emphasizes the maintenance of physical, cognitive, and social well-being in older adults16,17,18. This framework suggests that HL may not only serve as a sensory deficit but also as an early marker of systemic decline, amplifying the impact of other chronic diseases. Additionally, we employ the Multimorbidity Model19, which highlights the overlapping pathophysiological mechanisms that contribute to diseases such as diabetes, CVD, stroke, and depression. This model helps us understand how these diseases interact with HL and how they collectively contribute to the overall burden of disease.

The aim of this study is to provide a comprehensive global analysis of the burden of HL and its comorbidity with chronic diseases. By examining trends over time and across different demographic groups, this study will provide evidence to inform public health strategies for addressing aging populations and multimorbidity.

Materials and methods

Data sources

This study utilized data from the Global Burden of Disease Study 2021 (GBD 2021), provided by the Institute for Health Metrics and Evaluation (IHME). The GBD 2021 database provides comprehensive health metrics at global, regional, and national levels, including prevalence, incidence, mortality rates, Years Lived with Disability (YLDs), and Disability-Adjusted Life Years (DALYs), covering over 300 diseases. The data were retrieved from the GBD Results Tool (https://vizhub.healthdata.org/gbd-results/), which allows access to standardized health metrics.

The study focuses on individuals aged 45 and older and analyzes diseases such as HL, diabetes, CVD, and stroke. Data were stratified by age, sex, and region, and trends from 1990 to 2021 were examined.

Data processing and cleaning

Data cleaning and preparation were performed to ensure the integrity of the dataset for analysis:

Missing Data: Records with missing critical variables (e.g., YLDs, DALYs) were excluded from the analysis. For non-critical missing data, imputation methods were employed based on statistical techniques to ensure minimal bias.

Outlier Detection: Outliers were identified using boxplots and removed if they exceeded 1.5 times the interquartile range (IQR), following standard statistical procedures for outlier detection.

Age Group and Sex Stratification: The dataset was filtered to include individuals aged 45 and older. Stratification by sex (Male, Female, Both) was performed to explore potential gender differences in disease burden. This allowed for more detailed analysis of age- and sex-related trends across different regions.

Metrics

Analyses were based on YLDs reported as Number and Rate in the GBD dataset. These two metrics allow the assessment of absolute burden (Number) and relative burden adjusted for population size (Rate). No additional age-standardized metrics (ASR, SIR, SPR) were applied.

Statistical analysis

Several statistical methods were applied to analyze the data:

Multivariate Linear Regression: Used to examine the relationship between chronic conditions (diabetes, CVD, stroke) and HL, measured in YLDs. Regression coefficients (β) and p-values were computed to determine the strength and significance of these associations.

Pearson Correlation Analysis: Employed to assess the strength and direction of relationships between HL and comorbid chronic diseases. A correlation matrix was created to visualize these relationships.

Trend Forecasting: A linear trend extrapolation based on historical data from 1990 to 2021 was applied to forecast future trends in HL YLDs up to 2030.

Software: All statistical analyses were conducted using Python 3.10, with libraries such as pandas, statsmodels, and matplotlib for data manipulation, statistical modeling, and visualization.

Data visualization

To ensure the results were presented clearly and effectively, several data visualization techniques were applied:

Trend plots: To illustrate annual changes in HL and other chronic diseases (diabetes, CVD, stroke, depression) from 1990 to 2021.

Boxplots: To display the distribution of YLDs for HL by age group and sex, providing insight into demographic variation.

Correlation heatmaps: To visualize the strength of associations between HL and comorbid conditions. Both time-series correlations (1990–2021) and a cross-sectional regional correlation analysis for 2021 were conducted.

Results

Global trends in YLDs

From 1990 to 2021, global YLDs for all four chronic conditions analyzed—age-related HL, diabetes mellitus, CVD, and stroke—increased substantially. HL YLDs rose from 28.7 million to 67.9 million (+ 136.7%), reflecting the mounting burden of sensory impairment associated with population aging. Diabetes exhibited the steepest growth, with YLDs increasing from 16.1 million to 66.4 million (+ 311.9%). Similarly, CVD YLDs rose from 23.7 million to 53.0 million (+ 123.8%), and stroke-related YLDs increased from 12.0 million to 25.6 million (+ 112.6%).

This growth was particularly pronounced in individuals aged 65 years and older, aligning with global aging patterns. Regionally, the burden of HL was highest in East Asia and Pacific, particularly in China, due to demographic scale and age structure. However, the highest age-standardized rates (ASRs) were observed in countries with larger elderly populations, such as those in Europe and North America.

For diabetes, the burden was disproportionately high in regions with younger populations, including Sub-Saharan Africa and South Asia. These disparities highlight the interplay of demographic and epidemiologic transitions across regions.

Figure 1 presents global trends in YLDs from 1990 to 2021 for the four conditions, showing consistent and substantial increases across all diseases, especially for diabetes and HL.

Fig. 1
figure 1

This line plot shows the global trend of HL and major chronic diseases (diabetes, CVD, stroke) from 1990 to 2021, measured by YLDs. HL demonstrates a consistent rise across the decades, underscoring its growing public health impact.

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Multivariate regression analysis

Multivariate regression analysis was used to examine the relationship between HL and the selected chronic conditions. The regression models revealed the following:

Diabetes: A weak and non-significant association was observed between diabetes and HL (coefficient = 0.031, p = 0.675).

CVD: The relationship between CVD and HL was negative and statistically significant (coefficient = −1.374, p = 0.0016). This may reflect the influence of multicollinearity and unmeasured confounders.

Stroke: A significant positive association was found between stroke and HL (coefficient = 1.798, p = 0.0010).

These findings indicate that stroke is a key contributor to the burden of HL, while diabetes was not independently associated, and CVD showed a negative but unstable relationship.

Depression regression analysis

Regression models examining the relationship between HL and depressive disorders also revealed a significant positive association:

HL (YLDs): Coefficient (β) = 0.218, p < 0.001.

This indicates that for every increase of 10,000 YLDs from HL, depression YLDs increased by approximately 2,180, highlighting a strong relationship between HL and depression.

Correlation analysis

A Pearson correlation matrix was calculated to assess the relationships between HL and chronic diseases over time. The strongest associations were observed between HL and CVD (r = 0.72), diabetes (r = 0.68), and depression (r = 0.55), indicating that HL is closely linked with these conditions in long-term temporal trends.

Figure 2 compares the average HL burden (YLDs) across World Bank-defined regions. East Asia & Pacific and Europe & Central Asia report the highest burdens, likely linked to aging demographics and better diagnostic/reporting systems.

Fig. 2
figure 2

This bar chart compares the average HL burden (YLDs) across World Bank-defined regions. East Asia & Pacific and Europe & Central Asia report the highest burdens, likely linked to aging demographics and better diagnostic/reporting systems.

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Regional and gender differences

Significant regional differences were observed in the burden of HL. East Asia & Pacific, particularly China, had the highest absolute burden of HL. However, age-standardized rates were highest in regions with larger aging populations, including parts of Europe and North America.

Gender differences were also observed in the burden of HL. Women, particularly those aged 65 and older, reported significantly higher YLDs for HL and depression compared to men (10.48 M vs. 9.06 M in 2021). This aligns with previous findings, which suggest that older women are more vulnerable to both HL and associated mental health issues.

Figure 3 illustrates the average HL burden in China, the United States, and India, with China showing the highest burden.

Fig. 3
figure 3

This bar chart illustrates the average HL burden in China, the United States, and India. The United States displays the highest burden, with China and India showing growing trends influenced by demographic transitions.

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Forecasting of future trends

Using the linear trend extrapolation model, we projected the global burden of HL YLDs to 2030. The forecast predicts an additional increase of 18.3% in YLDs from HL, reaching an estimated 75.6 million by 2030. This projection underscores the growing global health challenge posed by HL, particularly in aging populations.

Figure 4 highlights the distribution of YLDs for HL across different age groups and by gender. The burden intensifies with age, and women tend to report slightly higher median values, especially in older age brackets.

Fig. 4
figure 4

This boxplot highlights the distribution of YLDs for HL across different age groups and by gender. The burden intensifies with age, and women tend to report slightly higher median values, especially in older age brackets.

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Additional correlation visualization

To further illustrate the associations between HL and chronic diseases, we constructed a Pearson correlation heatmap across world regions for 2021 (age ≥ 45 years). Figure 5 shows that HL was moderately positively correlated with stroke (r = 0.54), moderately negatively correlated with diabetes (r = −0.58), and weakly negatively correlated with CVD (r = −0.16). These findings suggest that, on a regional scale, HL aligns more closely with stroke burden, while its distribution diverges from that of diabetes and CVD.

Fig. 5
figure 5

Pearson correlation heatmap of YLDs for HL, diabetes, CVD, and stroke across world regions in 2021 (age ≥ 45 years). Correlation coefficients are based on aggregated regional YLDs. HL shows a moderate positive correlation with stroke, but weaker or negative correlations with diabetes and CVD.

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Discussion

This study offers a global comparative assessment of HL and its intersection with major chronic diseases in adults aged 45 and older. Over the 32-year period covered by GBD 2021 data, HL has shown a marked increase in prevalence and has emerged as a significant contributor to multimorbidity in aging populations. These findings strengthen the argument that sensory impairments—particularly HL—should be treated as an integral part of chronic disease management and healthy aging policies.

Within the framework of healthy aging, HL is more than a sensory limitation—it directly affects older adults’ ability to function, communicate, and maintain social engagement. Evidence increasingly links HL to depression, cognitive impairment, and CVD, all of which accelerate physical and psychological decline. These associations highlight the importance of preserving sensory function to sustain intrinsic capacity, as emphasized in the WHO healthy aging model20,21. When left unaddressed, HL can initiate or intensify a cascade of health deterioration in later life22.

The observed associations between HL and chronic conditions—particularly CVD, diabetes, and stroke—align with the Multimorbidity Model, which highlights overlapping pathophysiological pathways such as vascular dysfunction and metabolic disturbance4,5,6. In our cross-sectional regression analyses, stroke showed a significant positive association with HL, whereas diabetes was not significant, and CVD demonstrated a negative but statistically significant coefficient. However, these results were strongly affected by multicollinearity, limiting their robustness. These interconnections underscore the need for integrated risk assessment and care planning. Rather than addressing HL in isolation, it should be routinely included in comprehensive evaluations of older adults, especially in primary care and geriatric settings.

Regional disparities in HL burden reflect underlying socioeconomic inequalities and differences in healthcare infrastructure. In low- and middle-income countries, underdiagnosis and limited access to audiological services likely contribute to underreported prevalence, despite increasing risks23. Conversely, higher burdens in high-income settings may reflect more comprehensive screening rather than actual disease incidence24. These patterns call for context-specific strategies: expanding access to affordable screening and treatment in underserved areas, while promoting integrated care in resource-rich regions.

Disparities by sex and age further reveal inequities in health outcomes. Older women face a disproportionate burden of HL and depression, with our data showing that in 2021 YLDs for HL were higher in females (10.48 million) than in males (9.06 million) aged ≥ 65 years. Possible explanations include longer life expectancy25, caregiving responsibilities26, and lower access to specialized care27. In contrast, older men bear a higher burden of cardiovascular comorbidity. These patterns emphasize the importance of sex-sensitive approaches in designing effective aging and public health interventions.

Our findings support a shift from siloed, disease-specific strategies toward holistic, life-course approaches to health. Despite their widespread impact, sensory impairments are often excluded from chronic disease frameworks. Integrating hearing screening and rehabilitation into national aging and non-communicable disease strategies may not only enhance quality of life but also delay the onset of frailty, reduce cognitive decline, and prevent premature dependency—yielding long-term public health and economic benefits.

While this study benefits from robust global estimates provided by the GBD 2021 database, limitations remain. Modeled estimates depend on source data quality, which varies across countries. Moreover, the data do not capture HL severity or type, and the cross-sectional nature of the analysis limits causal inference. Future longitudinal studies are needed to clarify causal pathways and assess the effectiveness of integrated interventions in real-world settings.

This study provides important insights into the rising burden of HL and its associations with chronic diseases such as diabetes, stroke, and depression. Stroke appears to contribute significantly, diabetes was not independently associated, and the relationship with CVD was statistically significant but unstable due to multicollinearity. These findings underscore the necessity of integrating hearing care into chronic disease management frameworks, especially in the context of aging populations. Given the global demographic shift toward older age structures, health systems must adopt a more holistic and proactive approach that incorporates auditory health as a key component of geriatric and multimorbidity care. Policymakers should prioritize early screening, cross-disciplinary interventions, and regionally tailored strategies to mitigate the compounded burden of HL and comorbid chronic diseases. Doing so will not only improve quality of life but also reduce long-term healthcare costs and societal impact.

Conclusion

This study underscores the rising burden of HL and its strong comorbidity with chronic diseases such as cardiovascular conditions, diabetes, stroke, and depression among adults aged 45 and above. Framed within the WHO’s Healthy Aging model and the multimorbidity framework, our findings highlight HL as a critical, yet often overlooked, contributor to functional decline and systemic health deterioration in older populations.

Beyond being a sensory deficit, HL interacts with physical and mental health conditions in complex, bidirectional ways that amplify overall disease burden. These interconnections suggest that HL must be integrated into routine chronic disease management, particularly in primary care settings. Early detection and intervention could delay cognitive and functional decline, reduce healthcare costs, and support healthier, more independent aging.

Regional, age, and sex disparities in burden point to the need for equity-focused, context-specific public health strategies. As global populations continue to age, incorporating hearing health into broader aging and NCD policies is not optional—it is essential. Future research should continue exploring causal pathways and assess the real-world impact of integrated interventions. Policymakers should prioritize early hearing screening and rehabilitation programs as part of national strategies for aging and chronic disease control, especially in underserved populations.