Global estimates on the number of people blind or visually impaired by cataract: a meta-analysis from 2000 to 2020.

BACKGROUND: To estimate global and regional trends from 2000 to 2020 of the number of persons visually impaired by cataract and their proportion of the total number of vision-impaired individuals. METHODS: A systematic review and meta-analysis of published population studies and gray literature from 2000 to 2020 was carried out to estimate global and regional trends. We developed prevalence estimates based on modeled distance visual impairment and blindness due to cataract, producing location-, year-, age-, and sex-specific estimates of moderate to severe vision impairment (MSVI presenting visual acuity <6/18, ≥3/60) and blindness (presenting visual acuity <3/60). Estimates are age-standardized using the GBD standard population. RESULTS: In 2020, among overall (all ages) 43.3 million blind and 295 million with MSVI, 17.0 million (39.6%) people were blind and 83.5 million (28.3%) had MSVI due to cataract blind 60% female, MSVI 59% female. From 1990 to 2020, the count of persons blind (MSVI) due to cataract increased by 29.7%(93.1%) whereas the age-standardized global prevalence of cataract-related blindness improved by -27.5% and MSVI increased by 7.2%. The contribution of cataract to the age-standardized prevalence of blindness exceeded the global figure only in South Asia (62.9%) and Southeast Asia and Oceania (47.9%). CONCLUSIONS: The number of people blind and with MSVI due to cataract has risen over the past 30 years, despite a decrease in the age-standardized prevalence of cataract. This indicates that cataract treatment programs have been beneficial, but population growth and aging have outpaced their impact. Growing numbers of cataract blind indicate that more, better-directed, resources are needed to increase global capacity for cataract surgery.

Hearing Loss Prevalence, Years Lived With Disability, and Hearing Aid Use in the United States From 1990 to 2019: Findings From the Global Burden of Disease Study.

OBJECTIVES: This article describes key data sources and methods used to estimate hearing loss in the United States, in the Global Burden of Disease study. Then, trends in hearing loss are described for 2019, including temporal trends from 1990 to 2019, changing prevalence over age, severity patterns, and utilization of hearing aids. DESIGN: We utilized population-representative surveys from the United States to estimate hearing loss prevalence for the Global Burden of Disease study. A key input data source in modeled estimates are the National Health and Nutrition Examination Surveys (NHANES), years 1988 to 2010. We ran hierarchical severity-specific models to estimate hearing loss prevalence. We then scaled severity-specific models to sum to total hearing impairment prevalence, adjusted estimates for hearing aid coverage, and split estimates by etiology and tinnitus status. We computed years lived with disability (YLDs), which quantifies the amount of health loss associated with a condition depending on severity and creates a common metric to compare the burden of disparate diseases. This was done by multiplying the prevalence of severity-specific hearing loss by corresponding disability weights, with additional weighting for tinnitus comorbidity. RESULTS: An estimated 72.88 million (95% uncertainty interval (UI) 68.53 to 77.30) people in the United States had hearing loss in 2019, accounting for 22.2% (20.9 to 23.6) of the total population. Hearing loss was responsible for 2.24 million (1.56 to 3.11) YLDs (3.6% (2.8 to 4.7) of total US YLDs). Age-standardized prevalence was higher in males (17.7% [16.7 to 18.8]) compared with females (11.9%, [11.2 to 12.5]). While most cases of hearing loss were mild (64.3%, 95% UI 61.0 to 67.6), disability was concentrated in cases that were moderate or more severe. The all-age prevalence of hearing loss in the United States was 28.1% (25.7 to 30.8) higher in 2019 than in 1990, despite stable age-standardized prevalence. An estimated 9.7% (8.6 to 11.0) of individuals with mild to profound hearing loss utilized a hearing aid, while 32.5% (31.9 to 33.2) of individuals with hearing loss experienced tinnitus. Occupational noise exposure was responsible for 11.2% (10.2 to 12.4) of hearing loss YLDs. CONCLUSIONS: Results indicate large burden of hearing loss in the United States, with an estimated 1 in 5 people experiencing this condition. While many cases of hearing loss in the United States were mild, growing prevalence, low usage of hearing aids, and aging populations indicate the rising impact of this condition in future years and the increasing importance of domestic access to hearing healthcare services. Large-scale audiometric surveys such as NHANES are needed to regularly assess hearing loss burden and access to healthcare, improving our understanding of who is impacted by hearing loss and what groups are most amenable to intervention.

Trends in cardiovascular diseases burden and vascular risk factors in Italy: The Global Burden of Disease study 1990-2017.

AIMS: An exhaustive and updated estimation of cardiovascular disease burden and vascular risk factors is still lacking in European countries. This study aims to fill this gap assessing the global Italian cardiovascular disease burden and its changes from 1990 to 2017 and comparing the Italian situation with European countries. METHODS: All accessible data sources from the 2017 Global Burden of Disease study were used to estimate the cardiovascular disease prevalence, mortality and disability-adjusted life years and cardiovascular disease attributable risk factors burden in Italy from 1990 to 2017. Furthermore, we compared the cardiovascular disease burden within the 28 European Union countries. RESULTS: Since 1990, we observed a significant decrease of cardiovascular disease burden, particularly in the age-standardised prevalence (-12.7%), mortality rate (-53.8%), and disability-adjusted life years rate (-55.5%). Similar improvements were observed in the majority of European countries. However, we found an increase in all-ages prevalence of cardiovascular diseases from 5.75 m to 7.49 m Italian residents. Cardiovascular diseases still remain the first cause of death (34.8% of total mortality). More than 80% of the cardiovascular disease burden could be attributed to known modifiable risk factors such as high systolic blood pressure, dietary risks, high low density lipoprotein cholesterol, and impaired kidney function. CONCLUSIONS: Our study shows a decline in cardiovascular mortality and disability-adjusted life years, which reflects the success in reducing disability, premature death and early incidence of cardiovascular diseases. However, the burden of cardiovascular diseases is still high. An approach that includes the cooperation and coordination of all stakeholders of the Italian National Health System is required to further reduce this burden.

Establishing the Biofidelity of a Multiphysics Finite Element Model of the Human Heart.

PURPOSE: Accelerating development of new therapeutic cardiac devices remains a clinical and technical priority. High-performance computing and the emergence of functional and complex in silico models of human anatomy can be an engine to accelerate the commercialization of innovative, safe, and effective devices. METHODS: An existing three-dimensional, nonlinear model of a human heart with flow boundary conditions was evaluated. Its muscular tissues were exercised using electrophysiological boundary conditions, creating a dynamic, electro-mechanical simulation of the kinetics of the human heart. Anatomic metrics were selected to characterize the functional biofidelity of the model based on their significance to the design of cardiac devices. The model output was queried through the cardiac cycle and compared to in vivo literature values. RESULTS: For the kinematics of mitral and aortic valves and curvature of coronary vessels, the model's performance was at or above the 95th percentile range of the in vivo data from large patient cohorts. One exception was the kinematics of the tricuspid valve. The model's mechanical use environment would subject devices to generally conservative use conditions. CONCLUSIONS: This conservative simulated use environment for heart-based medical devices, and its judicious application in the evaluation of medical devices is justified, but careful interpretation of the results is encouraged.

The burden of cardiovascular diseases in Ethiopia from 1990 to 2017: evidence from the Global Burden of Disease Study.

In Ethiopia, evidence on the national burden of cardiovascular diseases (CVDs) is limited. To address this gap, this systematic analysis estimated the burden of CVDs in Ethiopia using the Global Burden of Disease (GBD) 2017 study data. The age-standardized CVD prevalence, disability-adjusted life years (DALYs) and mortality rates in Ethiopia were 5534 (95% uncertainty interval [UI] 5310.09 - 5774.0), 3549.6 (95% UI 3229.0 - 3911.9) and 182.63 (95% UI 165.49 - 203.9) per 100 000 population, respectively. Compared with 1990, the age-standardized CVD prevalence rate in 2017 showed no change. But significant reductions were observed in CVD mortality (54.7%), CVD DALYs (57.7%) and all-cause mortality (53.4%). The top three prevalent CVDs were ischaemic heart disease, rheumatic heart disease and stroke in descending order. The reduction in the mortality rate due to CVDs is slower than for communicable, maternal, neonatal and nutritional disease mortalities. As a result, CVDs are the leading cause of mortality in Ethiopia. These findings urge Ethiopia to consider CVDs as a priority public health problem.

Prevalence and causes of vision loss in China from 1990 to 2019: findings from the Global Burden of Disease Study 2019.

BACKGROUND: Vision loss is an important public health issue in China, but a detailed understanding of national and regional trends in its prevalence and causes, which could inform health policy, has not been available. This study aimed to assess the prevalence, causes, and regional distribution of vision impairment and blindness in China in 1990 and 2019. METHODS: Data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 were used to estimate the prevalence of moderate and severe vision impairment and blindness in China and compare with other Group of 20 (G20) countries. We used GBD methodology to systematically analyse all available demographic and epidemiological data at the provincial level in China. We compared the age-standardised prevalences across provinces, and the changes in proportion of vision loss attributable to various eye diseases in 1990 and 2019. We used two different counterfactual scenarios with respect to population structure and age-specific prevalence to assess the contribution of population growth and ageing to trends in vision loss. FINDINGS: In 2019, the age-standardised prevalence was 2·57% (uncertainty interval [UI] 2·28-2·86) for moderate vision impairment, 0·25% (0·22-0·29) for severe vision impairment, and 0·48% (0·43-0·54) for blindness in China, which were all below the global average, but the prevalence of moderate and severe vision impairment had increased more rapidly than in other G20 countries from 1990 to 2019. The prevalence of vision loss increased with age, and the main causes of vision loss varied across age groups. The leading causes of vision impairment in China were uncorrected refractive error, cataract, and macular degeneration in both 1990 and 2019 in the overall population. From 1990 to 2019, the number of people with moderate vision impairment increased by 133·67% (from 19·65 to 45·92 million), those with severe vision impairment increased by 147·14% (from 1·89 to 4·67 million), and those with blindness increased by 64·35% (from 5·29 to 8·69 million); in each case, 20·16% of the increase could be explained by population growth. The contributions to these changes by population ageing were 87·22% for moderate vision impairment, 116·06% for severe vision impairment, and 99·22% for blindness, and the contributions by age-specific prevalence were 26·29% for moderate vision impairment, 10·91% for severe vision impairment, and -55·04% for blindness. The prevalence and specific causes of vision loss differed across provinces. INTERPRETATION: Although a comprehensive national policy to prevent blindness is in place, public awareness of visual health needs improving, and reducing the prevalence of moderate and severe vision impairment should be prioritised in future work. FUNDING: China National Key Research and Development Programme and Beijing Municipal Special Funds for Medical Research on Public Welfare Development and Reform.

Cartilage Strain Distributions Are Different Under the Same Load in the Central and Peripheral Tibial Plateau Regions.

There is increasing evidence that the regional spatial variations in the biological and mechanical properties of articular cartilage are an important consideration in the pathogenesis of knee osteoarthritis (OA) following kinematic changes at the knee due to joint destabilizing events (such as an anterior cruciate ligament (ACL) injury). Thus, given the sensitivity of chondrocytes to the mechanical environment, understanding the internal mechanical strains in knee articular cartilage under macroscopic loads is an important element in understanding knee OA. The purpose of this study was to test the hypothesis that cartilage from the central and peripheral regions of the tibial plateau has different internal strain distributions under the same applied load. The internal matrix strain distribution for each specimen was measured on osteochondral blocks from the tibial plateau of mature ovine stifle joints. Each specimen was loaded cyclically for 20 min, after which the specimen was cryofixed in its deformed position and freeze fractured. The internal matrix was viewed in a scanning electron microscope (SEM) and internal strains were measured by quantifying the deformation of the collagen fiber network. The peak surface tensile strain, maximum principal strain, and maximum shear strain were compared between the regions. The results demonstrated significantly different internal mechanical strain distributions between the central and peripheral regions of tibial plateau articular cartilage under both the same applied load and same applied nominal strain. These differences in the above strain measures were due to differences in the deformation patterns of the collagen network between the central and peripheral regions. Taken together with previous studies demonstrating differences in the biochemical response of chondrocytes from the central and peripheral regions of the tibial plateau to mechanical load, the differences in collagen network deformation observed in this study help to provide a fundamental basis for understanding the association between altered knee joint kinematics and premature knee OA.

Knee kinematics, cartilage morphology, and osteoarthritis after ACL injury.

This review examines a mechanism for the initiation of osteoarthritis after anterior cruciate ligament (ACL) injury by considering the relationship between reported ambulatory changes after ACL injury, cartilage adaptation to load, and the association between cartilage loads during walking and regional variations in cartilage structure and biology. Taken together, these observations suggest that cartilage degeneration after ACL injury could be caused by a kinematic gait change that shifts ambulatory loading applied to cartilage. Such a shift may cause regions of cartilage to become newly loaded, be subjected to altered levels of compression and tension, or become unloaded. The metabolic sensitivity of chondrocytes to such changes in their mechanical environment, combined with the low adaptation potential of mature cartilage, could lead to cartilage degeneration and premature osteoarthritis after ACL injury. This proposed mechanism demonstrates the value of using the ACL injury model to understand the relationship between mechanics and biology, as well as helping to explain the importance of restoring normal ambulatory kinematics after ACL injury to avoid premature osteoarthritis.

Rotational changes at the knee after ACL injury cause cartilage thinning.

We examined the relationship between specific gait changes after anterior cruciate ligament injury and the progression of osteoarthritis at the knee. The study was done using a finite-element model derived from subject specific three-dimensional cartilage volumes created from magnetic resonance images. Cartilage thinning was predicted using an iterative algorithm based on the octahedral shear stress. Simulations were done for a knee with normal alignment and for a knee with an internal tibial rotation offset, as associated with anterior cruciate ligament deficiency. For the healthy knee, the model predicted patterns of cartilage thinning consistent with a previous clinical report of idiopathic osteoarthritis. For the ACL-deficient scenario the model predicted a more rapid rate of cartilage thinning throughout the knee, especially in the medial compartment. The results suggest that the progression of osteoarthritis after anterior cruciate ligament injury is associated with a shift in the normal load bearing regions of the knee joint during normal function due to kinematic changes, and highlight the importance of restoring proper gait during anterior cruciate ligament reconstruction.