Diabetes mellitus and risk of age-related macular degeneration: a systematic review and meta-analysis

Genome-wide association analyses identify 139 loci associated with macular thickness in the UK Biobank cohort

The macula, located near the center of the retina in the human eye, is responsible for providing critical functions, such as central, sharp vision. Structural changes in the macula are associated with many ocular diseases, including age-related macular degeneration (AMD) and glaucoma. Although macular thickness is a highly heritable trait, there are no prior reported genome-wide association studies (GWASs) of it. Here we describe the first GWAS of macular thickness, which was measured by spectral-domain optical coherence tomography using 68 423 participants from the UK Biobank cohort. We identified 139 genetic loci associated with macular thickness at genome-wide significance (P < 5 × 10-8). The most significant loci were LINC00461 (P = 5.1 × 10-120), TSPAN10 (P = 1.2 × 10-118), RDH5 (P = 9.2 × 10-105) and SLC6A20 (P = 1.4 × 10-71). Results from gene expression demonstrated that these genes are highly expressed in the retina. Other hits included many previously reported AMD genes, such as NPLOC4 (P = 1.7 × 10-103), RAD51B (P = 9.1 × 10-14) and SLC16A8 (P = 1.7 × 10-8), further providing functional significance of the identified loci. Through cross-phenotype analysis, these genetic loci also exhibited pleiotropic effects with myopia, neurodegenerative diseases (e.g. Parkinson's disease, schizophrenia and Alzheimer's disease), cancer (e.g. breast, ovarian and lung cancers) and metabolic traits (e.g. body mass index, waist circumference and type 2 diabetes). Our findings provide the first insight into the genetic architecture of macular thickness and may further elucidate the pathogenesis of related ocular diseases, such as AMD.

Early impairments in the retina of rats fed with high fructose/high fat diet are associated with glucose metabolism deregulation but not dyslipidaemia

Way of life changes such as high consumption of processed foods rich in fat and sugar and sedentary lifestyle are associated with the increasing prevalence of metabolic syndrome (MetS) that affects about 35% in the American population. MetS is the main risk factor for diabetes mellitus, which is associated with vascular changes in the retina. However, the early consequences of MetS in the retina are not well described. We therefore aimed at characterizing the early effects of a high fructose and high fat diet (HFHF) on the function and structure of the rat retina, and evaluate the associations with metabolic changes. Brown Norway rats of 6 weeks of age were fed for 8 days, 5 weeks or 13 weeks with HFHF diet, or a standard chow. After only 4 weeks of this diet, rats exhibited a reduction in cone photoreceptor sensitivity to light. Moreover, we observed that MetS significantly exacerbated laser-induced choroidal neovascularization by 72% and 67% 2 weeks and 3 weeks post laser treatment, respectively. These retinal abnormalities were associated with deregulation of glucose metabolism but not lipid metabolism. These data showed retinal modifications in HFHF-induced MetS in the rat, at very early stage of the disease.

The Common Antidiabetic Drug Metformin Reduces Odds of Developing Age-Related Macular Degeneration

Purpose

AMD is the leading cause of irreversible blindness in older individuals in the Western world, and there are currently no therapies to halt disease progression. Studies suggest that the commonly prescribed antidiabetic drug, metformin, is associated with decreased risk of several ocular diseases, but no work has investigated the effect of metformin use on development of AMD. Thus, we aim to investigate whether metformin use is associated with decreased risk of developing AMD.

Methods

In this retrospective case-control study, we used medical records from patients older than 55 who have visited a University of Florida health clinic. Three controls were matched for every AMD case, defined by International Classification of Diseases, Ninth Revision code, based on the Charlson Comorbidity Index to ensure comparable baseline overall health status. Univariate and conditional multivariable logistic regressions were used to determine the association between a variety of covariates, including metformin use, and AMD diagnosis.

Results

Metformin use was associated with decreased odds of developing AMD, independently of the other covariates investigated, with an odds ratio of 0.58 and a 95% confidence interval of 0.43 to 0.79. Other medications assessed were not associated with decreased odds of developing AMD.

Conclusions

Patients who had taken metformin had decreased odds of developing AMD, suggesting that metformin may have a therapeutic role in AMD development or progression in those who are at risk. Further work should include clinical trials to investigate prospectively whether metformin has a protective effect in those at risk for developing AMD.

The Contribution of Fluoride to the Pathogenesis of Eye Diseases: Molecular Mechanisms and Implications for Public Health

This study provides diverse lines of evidence demonstrating that fluoride (F) exposure contributes to degenerative eye diseases by stimulating or inhibiting biological pathways associated with the pathogenesis of cataract, age-related macular degeneration and glaucoma. As elucidated in this study, F exerts this effect by inhibiting enolase, τ-crystallin, Hsp40, Na⁺, K⁺-ATPase, Nrf2, γ -GCS, HO-1 Bcl-2, FoxO1, SOD, PON-1 and glutathione activity, and upregulating NF-κB, IL-6, AGEs, HsP27 and Hsp70 expression. Moreover, F exposure leads to enhanced oxidative stress and impaired antioxidant activity. Based on the evidence presented in this study, it can be concluded that F exposure may be added to the list of identifiable risk factors associated with pathogenesis of degenerative eye diseases. The broader impact of these findings suggests that reducing F intake may lead to an overall reduction in the modifiable risk factors associated with degenerative eye diseases. Further studies are required to examine this association and determine differences in prevalence rates amongst fluoridated and non-fluoridated communities, taking into consideration other dietary sources of F such as tea. Finally, the findings of this study elucidate molecular pathways associated with F exposure that may suggest a possible association between F exposure and other inflammatory diseases. Further studies are also warranted to examine these associations.

Systemic Inflammatory Disease and AMD Comorbidity

Prevalence of age-related macular degeneration (AMD), the leading cause of blindness in the United States, increases greatly with age. While age is the greatest risk factor of AMD, other risks such as smoking, family history, complement pathway activation, and race exist. Various systemic inflammatory diseases share many of these risk factors with AMD, as well as a similar inflammatory profile. Due to these similarities, patient database studies analyzing the association between patients with various systemic diseases and AMD have been performed. In this review we will summarize recent finding on this subject and discuss the implications on AMD diagnosis. By gaining greater insight into the association between chronic systemic inflammation and AMD, implications for novel therapeutic approaches to treat AMD pathology may be identified.

The Association Between Diabetes and Age-Related Macular Degeneration Among the Elderly in Taiwan

OBJECTIVE

To investigate the relationship between diabetes and future development of age-related macular degeneration (AMD).

RESEARCH DESIGN AND METHODS

Longitudinal, retrospective cohort study data for the period between 1997 and 2012 were obtained from the Longitudinal Health Insurance Database (LHID) of Taiwan. The final available 71,904 patients with diabetes and 270,213 patients without diabetes ≥50 years of age were further matched by age, sex, and Charlson comorbidity index. In the end, 54,616 study subjects in each of the diabetes and nondiabetes groups were recruited. The stratified populations of patients with diabetes with diabetic retinopathy (DR) (n = 7,119) versus those with diabetes who do not have DR (n = 7,119) and populations of patients with proliferative DR (PDR) (n = 2,134) versus those with nonproliferative DR (NPDR) (n = 2,134) were also obtained. Competing risk regression models were used to assess the adjusted hazard ratio (HR) and 99% CI. The main outcome measures were the first-ever diagnosis of AMD during the observational period.

RESULTS

The incidences of nonexudative AMD (HR 1.23; P = 0.108) and exudative AMD (HR 1.37; P = 0.023) were not significantly associated with cohorts of persons with diabetes compared with cohorts without diabetes. The stratified analysis showed that nonexudative AMD (HR 3.89; P = 0.001) and exudative AMD (HR 3.42; P < 0.001) were significantly correlated to diabetes with DR cohorts, compared with diabetes without DR cohorts. The incidences of nonexudative AMD (HR 0.53; P = 0.277) and exudative AMD (HR 2.27; P = 0.058) were not significantly different between PDR cohorts compared with NPDR cohorts.

CONCLUSIONS

This study provides large-scale, population-based evidence that diabetes with retinopathy is independently associated with an increased risk of subsequent AMD development.

Low incidence of choroidal neovascularization following subthreshold diode micropulse laser (SDM) in high-risk AMD

Purpose

To determine the incidence of new choroidal neovascularization (CNV) in eyes with dry age-related macular degeneration (AMD) following subthreshold diode micropulse laser (SDM).

Method

In an observational retrospective cohort study, the records of all patients active in the electronic medical records database were reviewed to identify eyes with dry AMD treated with SDM. Identified eyes were classified by simplified AREDS categories, and analyzed for the primary endpoint of new CNV after treatment.

Results

The EMR revealed SDM was offered to 373/392 (95%) patients with dry AMD and elected by 363/373 (97%) between 2008–2017. Follow up was available for 354/363 patients (547 eyes, 98%) (range 6–108 mos., avg. 22). CNV risk factors included age (median 84 years, 67% > 80); reticular pseudodrusen (214 eyes, 39%); AREDS category (78% category 3 and 4); and fellow eye CNV (128 eyes, 23%). New CNV developed in 9/547 eyes (1.6%, annualized rate 0.87%). Visual acuity was unchanged. There were no adverse treatment effects.

Summary

In a review of a large group of eyes with exceptionally high-risk AMD, SDM was followed by a very low incidence of new CNV. If confirmed by further study, SDM would offer a new and highly effective treatment to reduce the risk of vision loss from AMD.

A comparison of risk factors for age-related macular degeneration and polypoidal choroidal vasculopathy in Chinese patients

PURPOSE

Neovascular age-related macular degeneration (nAMD) and polypoidal choroidal vasculopathy (PCV) are important vision-threatening diseases worldwide. For effective treatment, the risk factors for the diseases merit investigation. This study aimed to compare the risk factors for nAMD vs. PCV in Chinese patients.

METHODS

A total of 946 participants were recruited in this case-control study, including 281 patients with nAMD, 306 patients with PCV, and 359 controls. All participants underwent comprehensive ophthalmic examinations. Information on risk factors were collected by questionnaire. Multivariate logistic regression analyses were performed to investigate the difference in risk factors between nAMD and PCV. In a subgroup of subjects, serum lipid data were obtained and analyzed.

RESULTS

Risk factors for nAMD included older age (OR 1.03, P = 0.001), male gender (OR 1.55, P = 0.020), asthma (OR 2.50, P = 0.028), smoking (OR 1.92, P = 0.001), and family history (OR 6.82, P = 0.001), while smoking (OR 1.67, P = 0.013) was the only risk factor for PCV. Compared to patients with PCV, patients with nAMD were more likely to be older and suffer from hyperlipidemia, coronary artery disease, rheumatism, and tumor. Interestingly, higher levels of high-density lipoprotein were positively associated with PCV in the subgroup analysis (OR 7.74, P = 0.011). Besides, results were quite different between the combination of patients with nAMD and PCV and patients with nAMD or PCV alone.

CONCLUSIONS

The risk factors for nAMD and PCV is varying with the exception of smoking. Our findings suggest that different strategies might be applied in the clinical management and scientific research on nAMD and PCV.

Comparison of direct sequencing and amplification refractory mutation system for detecting epidermal growth factor receptor mutation in non-small-cell lung cancer patients: a systematic review and meta-analysis

BACKGROUND

Direct sequencing and amplification refractory mutation system (ARMS) are commonly used to detect epidermal growth factor receptor (EGFR) mutation status in patients with non-small-cell lung cancer to inform the decision-making on tyrosine kinase inhibitors treatment. This study aimed to systematically compare the two methods in terms of the rate of detected mutations and the association of detected mutations with clinical outcomes.

MATERIAL AND METHODS

PubMed, EMBASE, China National Knowledge Infrastructure (in Chinese) and Wanfang database (in Chinese) were searched to identify relevant studies. Meta-analyses of EGFR mutation rates, rate differences, and the associations of EGFR mutations with clinical outcomes of tyrosine kinase inhibitors treatment were conducted.

RESULTS

Eight hundred and sixty-six records were retrieved and 26 studies with 3282 patients were included. The pooled rate of mutations detected by ARMS (41%, 95% confidence interval (CI) 35% to 47%) was significantly higher than that by direct sequencing (28%, 95%CI 22% to 34%), with a weighted rate difference of 11% (95%CI 8% to 13%). There was a consistent trend that the associations between ARMS-detected mutations and clinical outcomes were stronger than those between direct-sequencing-detected mutations and clinical outcomes (pooled risk ratio for objective response: 5.18 vs. 2.25; hazard ratio for progression-free survival: 0.30 vs. 0.42; hazard ratio for overall survival: 0.46 vs. 0.54).

CONCLUSIONS

More patients with EGFR mutations can be identified by ARMS than by direct sequencing, and those identified by ARMS seems to be able to benefit more from tyrosine kinase inhibitors than those identified by direct sequencing.

Age-Related Macular Degeneration in Patients With Chronic Myeloproliferative Neoplasms

Importance

It has been suggested that systemic inflammation increases the risk of age-related macular degeneration (AMD). Given that chronic immune modulation is present in patients with myeloproliferative neoplasms (MPNs), the risk of AMD in these patients may be increased.

Objective

To compare the risk of AMD in patients with MPNs with the risk of AMD in matched controls from the general population.

Design, Setting, and Participants

A nationwide population-based cohort study using Danish registers was conducted of all patients in Denmark who received a diagnosis between January 1, 1994, and December 31, 2013, of essential thrombocythemia, polycythemia vera, myelofibrosis, or unclassifiable MPNs. For each patient, 10 age- and sex-matched controls were included. All patients without prior AMD were followed up from the date of diagnosis (or corresponding entry date for the controls) until the first AMD diagnosis, death or emigration, or December 31, 2013, whichever occurred first. Data analysis was performed from April 1, 2015, to October 31, 2016.

Main Outcomes and Measures

Incidence of AMD recorded in specialized hospital-based care. The rates and absolute risk of AMD were calculated. Using Cox proportional hazards regression models, smoking and risk-time adjusted hazard ratios (HRs) between patients and controls were calculated. In addition, HRs of neovascular AMD after 2006 were calculated since antivascular endothelial growth factor treatment was introduced nationwide at hospitals thereafter.

Results

A total of 7958 patients with MPNs (4279 women [53.8%] and 3679 men [46.2%]; mean [SD] age at diagnosis, 66.4 [14.3] years) were included in the study. The rate of AMD per 1000 person-years at risk was 5.2 (95% CI, 4.6-5.9) for patients with MPNs (2628 with essential thrombocythemia, 3063 with polycythemia vera, 547 with myelofibrosis, and 1720 with unclassifiable MPNs) and 4.3 (95% CI, 4.1-4.4) for the 77 445 controls, while the 10-year risk of AMD was 2.4% (95% CI, 2.1%-2.8%) for patients with MPNs and 2.3% (95% CI, 2.2%-2.4%) for the controls. The risk of AMD was increased overall for patients with MPNs (adjusted HR, 1.3; 95% CI, 1.1-1.5), with adjusted HRs for the subtypes of 1.2 (95% CI, 1.0-1.6) for essential thrombocythemia, 1.4 (95% CI, 1.2-1.7) for polycythemia vera, 1.7 (95% CI, 0.8-4.0) for myelofibrosis, and 1.5 (95% CI, 1.1-2.1) for unclassifiable MPNs. In addition, patients with MPNs had a higher risk of neovascular AMD (adjusted HR, 1.4; 95% CI, 1.2-1.6).

Conclusions and Relevance

Our results suggest that patients with MPNs are at increased risk of AMD, supporting the possibility that systemic inflammation is involved in the pathogenesis of AMD.

Common eye diseases in older adults of southern Germany: results from the KORA-Age study

Purpose

a population-based study in the region of Augsburg (Germany, KORA) was used to identify the prevalence of eye diseases and their risk factors in a sample of aged individuals.

Methods

data originated from the KORA-Age study collected in 2012 and 822 participants (49.6% women, 50.4% men, aged 68–96 years) were asked standardised questions about eye diseases. Positive answers were validated and specified by treating ophthalmologists. Additional information came from laboratory data. Polymorphic markers were tested for candidate genes.

Results

we received validations and specifications for 339 participants. The most frequent eye diseases were cataracts (299 cases, 36%), dry eyes (120 cases, 15%), glaucoma (72 cases, 9%) and age-related macular degeneration (AMD) (68 cases, 8%). Almost all participants suffering from glaucoma or from AMD also had cataracts. Cataract surgery was associated with diabetes (in men; OR = 2.24; 95% confidence interval [CI] 1.11–4.53; P = 0.025) and smoking (in women; OR = 6.77; CI 1.62–28.35; P = 0.009). In men, treatments in airway diseases was associated with cataracts (glucocorticoids: OR = 5.29, CI 1.20–23.37; P = 0.028; sympathomimetics: OR = 4.57, CI 1.39–15.00; P = 0.012). Polymorphisms in two genes were associated with AMD (ARMS2: OR = 2.28, CI 1.48–3.51; P = 0.005; CFH: OR = 2.03, CI 1.35–3.06; P = 0.010).

Conclusion

combinations of eye diseases were frequent at old age. The importance of classical risk factors like diabetes, hypertension and airway diseases decreased either due to a survivor bias leaving healthier survivors in the older age group, or due to an increased influence of other up to now unknown risk factors.

Age-related macular degeneration in a South Indian population, with and without diabetes

PurposeTo elucidate the prevalence and risk factors of age-related macular degeneration (AMD) in people with diabetes.MethodsOf the 5495 subjects ≥60 years of age recruited in the population-based study in south India, 4791 subjects with gradable images on 30° three-field retinal photographs were analyzed. AMD and diabetic retinopathy (DR) were graded based on the International ARM Epidemiological Study Group classification and International Clinical Diabetic Retinopathy Disease Severity Scale, respectively. All subjects underwent a detailed history, physical examination, and a comprehensive ocular examination.ResultsOf the 4791 subjects, 1256 had diabetes. In those with diabetes, 166 (13.2%) had DR: of which, 9.6% had AMD. Of those with diabetes but no DR, 15.6% had AMD. Presence of DR (OR=0.57, 95% CI: 0.33-0.99, P=0.046) was a protective factor for AMD in diabetes. When adjusted for potential confounding factors, those with AMD and diabetes were from urban areas (OR=1.65, 95% CI: 1.09-2.49, P=0.018), had raised systolic blood pressure (OR=1.02, 95% CI: 1.00-1.03, P=0.01), higher BMI (OR=1.06, 95% CI: 1.02-1.10, P=0.005), and higher serum triglycerides (OR=1.00, 95% CI: 1.00-1.01, P=0.011). A higher level of high-density lipoprotein (HDL) (OR=0.98, 95% CI: 0.96-0.99, P=0.038) was a protective factor for AMD in subjects with diabetes.ConclusionsThe presence of DR and higher serum HDL are protective factors whereas obesity and higher systolic blood pressure are risk factors for AMD in subjects with diabetes.

Visual complications in diabetes mellitus: beyond retinopathy

Diabetic retinopathy is the most common cause of vision loss in people with diabetes mellitus; however, other causes of visual impairment/loss include other retinal and non-retinal visual problems, including glaucoma, age-related macular degeneration, non-arteritic anterior ischaemic optic neuropathy and cataracts. Additionally, when a person with diabetes complains of visual disturbance despite a visual acuity of 6/6, abnormalities in refraction, contrast sensitivity, straylight and amplitude of accommodation should be considered. We review and highlight these visual problems for physicians who manage people with diabetes to ensure timely referral and treatment to limit visual disability, which can have a significant impact on daily living, especially for those participating in sports and driving.

Visual and Morphologic Outcomes in Eyes with Hard Exudate in the Comparison of Age-Related Macular Degeneration Treatments Trials

PURPOSE

To compare baseline characteristics, visual acuity (VA) and morphological outcomes between eyes with baseline hard exudates (HE) and all other eyes among patients with neovascular age-related macular degeneration (NVAMD) treated with anti-vascular endothelial growth factors (anti-VEGF).

DESIGN

Prospective cohort study within the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT).

PARTICIPANTS

Patients with NVAMD.

METHODS

Readers evaluated baseline and follow-up morphology on digital color images, fluorescein angiography (FA), and optical coherence tomography (OCT) in eyes with NVAMD that were randomly assigned to treatment with either ranibizumab or bevacizumab. Ophthalmologists identified HE on color images in the study eye.

MAIN OUTCOME MEASURES

VA; scar; geographic atrophy; retinal thickness, fluid; and number of anti-VEGF injections.

RESULTS

HE was present in 128 of 1185 (11%) study eyes at baseline, 77% within 1 disc diameter of the foveal center. Patients with study eye HE were more likely female (81% vs 60%; p<0.001) and non-smokers (53% vs 42%; p=0.004). Both groups had similar proportions of hypercholesterolemia and hypertriglyceridemia. At baseline, eyes with HE had worse VA (mean 57 vs 61 letters; p=0.003), larger total lesion size (3.3 vs 2.4 DA; p <0.001), greater total foveal thickness (522µm vs 452µm; p<0.001), more retinal angiomatous proliferation (18% vs 10%; p=0.009) and sub-RPE fluid (65% vs 47%; p<0.001). At 1 year, VA was similar in both groups; more eyes with baseline HE had no fluid (45% vs 29%; p<0.001) and greater reduction in total foveal thickness (-266µm vs -158u; p<0.001). VA at year 2 was similar but retinas of eyes with baseline HE were thinner (267µm vs 299µm; p=0.03) and fewer eyes had sub-retinal fluid (23% vs 36%; p=0.008). HE was present in 19% of eyes at 1 year and 5% of eyes at 2 years. LIPC promoter SNP rs10468017 was not associated with NVAMD HE.

CONCLUSION

Eyes with HE have larger CNV lesions and more RAP. Their initially thicker retina rapidly becomes thinner on anti-VEGF treatment. HE is not significantly associated with hyperlipidemia. HE at baseline does not significantly influence VA, scar and GA outcomes in eyes with NVAMD treated with anti-VEGF. Few eyes have HE at year 2.

Integrated Approaches to Drug Discovery for Oxidative Stress-Related Retinal Diseases

Excessive oxidative stress induces dysregulation of functional networks in the retina, resulting in retinal diseases such as glaucoma, age-related macular degeneration, and diabetic retinopathy. Although various therapies have been developed to reduce oxidative stress in retinal diseases, most have failed to show efficacy in clinical trials. This may be due to oversimplification of target selection for such a complex network as oxidative stress. Recent advances in high-throughput technologies have facilitated the collection of multilevel omics data, which has driven growth in public databases and in the development of bioinformatics tools. Integration of the knowledge gained from omics databases can be used to generate disease-related biological networks and to identify potential therapeutic targets within the networks. Here, we provide an overview of integrative approaches in the drug discovery process and provide simple examples of how the approaches can be exploited to identify oxidative stress-related targets for retinal diseases.

C2 rs547154 polymorphism and polypoidal choroidal vasculopathy susceptibility: a meta-analysis

Previous studies have indicated the association between C2 rs547154 polymorphism and polypoidal choroidal vasculopathy (PCV) risk, while the results are controversial and inconsistent. Herein, we perform a meta-analysis to gain a precise estimation of the association using 5 eligible studies involving 4076 subjects, of which 1220 were PCV cases, 1073 were age-related macular degeneration (AMD) cases and 1783 were controls. Allelic frequencies of C2 rs547154 polymorphism between PCV and AMD were also compared. Both crude and adjusted odds ratios (OR) with their 95% confidence interval (CI) were included to assess the strength of the association. The pooled OR in random-effect model for allele T versus G was 0.64 (95% CI, 0.52–0.80; p < 0.0001), for genotype TG versus GG was 0.65 (95% CI, 0.52–0.83; p, 0.0004), and for genotype TT + TG versus GG was 0.64 (95% CI, 0.51–0.80; p, 0.0002). No difference in allelic frequency was observed between PCV and AMD (OR, 0.86; 95% CI, 0.64–1.16; p, 0.32). Sensitivity analysis proved the robustness of our data. No significant ethnic divergence was suggested by subgroup analysis, and no publication bias was detected via Egger's test. In conclusion, our data indicate that C2 rs547154 polymorphism plays a protective role in the development of PCV.