Prevalence of and factors associated with lens opacities in a Korean adult population with and without diabetes: the 2008-2009 Korea National Health and Nutrition Examination Survey

Prevalence and 11-Year Incidence of Cataract and Cataract Surgery and the Effects of Socio-Demographic and Lifestyle Factors

Purpose

To assess the impact of cataract in ageing population by evaluating the prevalence, incidence, and background factors of cataract and cataract surgery.

Patients and Methods

Two health examination surveys representing Finnish population in 2000 and 2011 included 7380 and 5930 participants aged 30 years or older with cataract status known. An 11-year follow-up included 4840 persons who participated in both the surveys. The data include information on physician-made diagnoses, socio-demographic factors, and lifestyle factors based on self-reported assessment. Cataract diagnoses and surgeries recorded in the Finnish Care Register for Health Care were linked to the survey data. Cataract patients were compared to those without cataract using logistic regression. Differences in cataract surgery age were evaluated using linear regression. Univariable and multivariable models were included.

Results

During 2000–2011, the prevalence of cataract increased from 8.8% to 13.6% and cataract surgery from 5.7% to 8.9% in a representative sample of the Finnish adult population. Cataract and cataract surgery were associated with age, smoking, and high alcohol consumption. Cataract was also associated with female gender and low income in 2000, but this association declined during the 11 years. Smoking and high alcohol consumption were associated with younger surgery age.

Conclusion

The prevalence of cataract and cataract surgery is increasing with the ageing of the population. The increase in cataract surgery is likely also reflecting the improvements in eye care. The possibility to equally use health-care services throughout a country can reduce the impact of socio-demographic status. Healthy lifestyle delays the development of cataract, whereas smoking and high alcohol consumption are associated with earlier cataract development. Therefore, the availability of cataract services and promotion of healthy lifestyle will be the key to prevent the detrimental effects of cataract on patients and the society in countries where the population is rapidly ageing.

Activation of autophagy inhibits epithelial to mesenchymal transition process of human lens epithelial cells induced by high glucose conditions

Subcapsular cataracts are common phenotype of diabetic cataracts, and abnormal lens epithelial cells (LECs) under the lens capsules have been considered to involve in the pathogenesis. Our previous studies have shown that the epithelial to mesenchymal transition (EMT), which is responsible for the LECs to lose their original polarity and tight junctions, occurs in a diabetic cataract mouse model. Autophagy is known to function in the EMT process in multiple tissues. However, the relationship between autophagy and EMT process in LECs has not yet been fully demonstrated. We found that high glucose retreatment reducing expression level of E-cadherin, an epithelial marker, but increasing that of α-smooth muscle actin (α-SMA), a mesenchymal marker, by Western blot and immunoflurence staining assays, and increased the cell migration by Transwell assay in human lens epithelial cell line HLE-B3. High glucose retreatment also led to impairment of autophagy, representing by downregulation of Beclin, LC3II/LC3I, and reducing the number of autophagosomes. Activation of autophagy by rapamycin could prevent high glucose-induced EMT. In addition, the levels of p62 and Snail were increased in high glucose-treated HLE-B3 cells, and their interactions were demonstrated by co-immunoprecipitation and immunoflurence staining, but all these changes were attenuated by application of rapamycin. These findings delineated a novel autophagy-mediated mechanism, p62 might mediate Snail underlying high glucose-induced EMT in LECs, suggesting a potential therapeutic approach for diabetic cataract by regulating autophagy.

Global and regional prevalence of age-related cataract: a comprehensive systematic review and meta-analysis

The aim of our study was to estimate regional and global cataract prevalence, its prevalence in different age groups, and the determinants of heterogeneity and its prevalence. For that, we used international databases such as PubMed, Web of Science, Scopus, Embase, and other sources of information to conduct a systematic search for all articles concerning the prevalence of age-related cataract and its types in different age groups. Of the 9922 identified articles, 45 studies with a sample size of 161,947 were included in the analysis, and most of them were from the Office for the Western Pacific Region (19 studies). Age- standardized pooled prevalence estimate (ASPPE) and 95% confidence interval (95% CI) of any cataract, cortical cataract, nuclear cataract, and posterior subcapsular (PSC) cataract were 17.20% (13.39-21.01), 8.05% (4.79-11.31), 8.22% (4.93-11.52), and 2.24% (1.41-3.07), respectively. Significant effects on heterogeneity were observed for the WHO region in the prevalence of any cataract (b: 6.30; p: 0.005) and study year in the prevalence of nuclear cataract (b: -0.66, p: 0.042). In general, the prevalence of cataract not only varies by region but also by age group, and most cases are over the age of 60 years. We examined the sources of variance in the prevalence of cataract and its different types, and identified age as a responsible factor in the prevalence of any cataract, cortical cataract, nuclear cataract, and PSC of cataract, WHO region in the prevalence of any cataract, and study year in the prevalence of nuclear cataract.

Patient Awareness of Cataract and Age-related Macular Degeneration among the Korean Elderly: A Population-based Study

PURPOSE

Age-related eye disease is often considered part of natural aging. Lack of awareness of eye conditions can result in missed treatment. We investigated the rates of awareness of cataract and age-related macular degeneration, the most common age-related eye-diseases, and the associated factors among elderly Koreans.

METHODS

We identified 7,403 study subjects (≥40 years old) with cataract or age-related macular degeneration based on ophthalmic examination results during the 5th Korean National Health and Nutrition Examination Survey conducted between 2010 and 2012. We assessed whether patients were aware of their eye condition based on a previous diagnosis by a physician.

RESULTS

The average awareness rate over the 3-year study period was 23.69% in subjects with cataract and 1.45% in subjects with age-related macular degeneration. Logistic regression analysis showed that patients with cataract were more likely to recognize their condition if they had myopia (odds ratio, 2.08), hyperopia (odds ratio, 1.33), family history of eye disease (odds ratio, 1.44), or a past eye examination (odds ratio, 4.07-29.10). The presence of diabetes mellitus was also a significant predictor of patient awareness of cataract (odds ratio, 1.88).

CONCLUSIONS

Poor patient recognition of eye disease among the Korean elderly highlights the seriousness of this potential public health problem in our aging society. Pre-existing eye-related conditions and diabetes were significant predictors of awareness; therefore, patients in frequent contact with their doctors have a greater chance of detecting eye disease.

An Overview of Ophthalmologic Survey Methodology in the 2008-2015 Korean National Health and Nutrition Examination Surveys

The Korea National Health and Nutrition Examination Survey (KNHANES) is a national program designed to assess the health and nutritional status of the noninstitutionalized population of South Korea. The KNHANES was initiated in 1998 and has been conducted annually since 2007. Starting in the latter half of 2008, ophthalmologic examinations were included in the survey in order to investigate the prevalence and risk factors of common eye diseases such as visual impairment, refractive errors, strabismus, blepharoptosis, cataract, pterygium, diabetic retinopathy, age-related macular degeneration, glaucoma, dry eye disease, and color vision deficiency. The measurements included in the ophthalmic questionnaire and examination methods were modified in the KNHANES IV, V, and VI. In this article, we provide detailed information about the methodology of the ophthalmic examinations in KNHANES in order to aid in further investigations related to major eye diseases in South Korea.

Sodium Intake and Socioeconomic Status as Risk Factors for Development of Age-Related Cataracts: The Korea National Health and Nutrition Examination Survey

Purpose

Cataract is a very prevalent ocular disorder, and environmental risk factors for age-related cataracts have been widely investigated. We aimed to evaluate an association of dietary sodium intake and socioeconomic factors with the development of age-related cataracts.

Methods

A cross-sectional case-control study based on the 2008–2011 Korea National Health and Nutrition Examination Survey. Dietary sodium intake was estimated using urinary sodium to creatinine ratio (U[Na⁺]/Cr).

Results

Among a total 12,693 participants, 2,687 (21.1%) had cataracts and 10,006 patients without cataracts served as controls. The prevalence of cataracts increased with age and quartiles of U[Na⁺]/Cr (p for trend < 0.001). Multivariate logistic regression analyses revealed that factors related to the development of cataracts were age ≥ 50 years (adjusted odds ratio [aOR] 15.34, 95% confidence interval [CI] 13.31‒17.69), low income (aOR 1.85, 95% CI 1.64–2.09), low educational attainment (aOR 1.76, 95% CI 1.57–1.96), and high sodium intake (U[Na⁺]/Cr > 16.4 mmol/mmol; aOR 1.29, 95% CI 1.16–1.44). In a subgroup analysis, a robust effect on cataracts across U[Na⁺]/Cr quartiles was observed in patients ≥ 50 years of age (aOR 1.11, 95% CI 1.04–1.18), though not in younger patients (aOR 1.06, 95% CI 0.96–1.17).

Conclusions

Our results suggest that high sodium intake and low socioeconomic status may affect the development of cataracts, and that a low-salt diet could be helpful for the prevention of cataracts in an older population. Furthermore, efforts to close gaps in health services due to socioeconomic factors may contribute to a reduction in the prevalence of cataracts.