Body mass index and the incidence of visually significant age-related maculopathy in men

BMI and plasma lipid levels with risk of proliferative diabetic retinopathy: a univariable and multivariable Mendelian randomization study

Background

The study aimed to determine whether a causal effect exists between body mass index (BMI) or plasma lipid levels and proliferative diabetic retinopathy (PDR) risk in humans.

Methods

We utilized univariable (UVMR) and multivariable two-sample Mendelian randomization (MVMR) analyses to confirm the effects of BMI and plasma lipid levels on the risk of PDR. Genetic variants associated with BMI and three plasma lipids were obtained from GWAS summary datasets generated by many different consortia and were deposited in the MR-Base database. The GWAS summary data for PDR from the FinnGen biobank included 2,12,889 participants of European ancestry (8,681 cases and 2,04,208 controls). Inverse variance weighted (IVW) was applied as the main MR analysis. Sensitivity analysis was used to evaluate the robustness of our findings.

Results

In the UVMR analysis, the causal associations of genetically predicted BMI with PDR presented a positive association (OR = 1.120, 95% CI = 1.076-1.167, P < 0.001), and the lower HDL-C level was associated with a higher risk of PDR (OR = 0.898, 95% CI = 0.811-0.995, P = 0.040). No evidence of an association between LDL-C or TG levels (P > 0.05) and PDR risk was found. In the MVMR analysis controlling for the HDL-C level, there was strong evidence for a direct causal effect of BMI on the risk of PDR (OR = 1.106, 95%CI = 1.049, 1.166, P < 0.001, IVW). After adjusting for BMI, there was no evidence for a direct causal effect of the HDL-C level on the risk of PDR (OR = 0.911, 95% CI = 0.823, 1.008, P = 0.072). Sensitivity analyses confirmed that the results were reliable and stable.

Conclusion

Robust evidence was demonstrated for an independent, causal effect of BMI in increasing the risk of PDR. Further studies are required to understand the potential biological mechanisms underlying this causal relationship.

A Study of Correlates of Age-Related Macular Degeneration in Patients Attending a Tertiary Hospital

Background

Age-related macular degeneration (ARMD) is a dreadful vision disease mainly affecting older people and causing permanent blindness if it remains undiagnosed and untreated. This study is particularly carried out to fill the gaps in the literature regarding the association of various systemic and environmental factors with ARMD.

Objective

We aim to study the correlates of age-related macular degeneration in patients attending a tertiary hospital.

Methods

This study is a hospital-based observational case-control study by nature with 260 participants included of ages more than 45 years. The participants were evaluated for risk factors after proper consenting.

Result

Age (56 years), diastolic blood pressure (DBP) of 80 mmHg, smoking cigarette for more than 10 years, sedentary lifestyle, body mass index (BMI) > 29.9 kg/m², sunlight exposure of more than eight hours, and higher lipid levels are determinants of ARMD.

Conclusion

Smoking is the strongest risk factor associated with ARMD, followed by diastolic blood pressure and body mass index. Lipid levels and a sedentary lifestyle have a weaker correlation with ARMD. However, age and gender are the most important determinants among non-modifiable factors.

Obesity and risk of age-related eye diseases: a systematic review of prospective population-based studies

BACKGROUND

Obesity is a public health challenge worldwide. The relationship between obesity and age-related eye diseases including cataract, glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy (DR) have remained elusive.

DESIGN AND METHODS

We conducted a systematic review of three electronic databases for longitudinal population-based studies that described associations between measures of obesity including body mass index (BMI), waist-circumference (WC), and waist-to-hip ratio (WHR), and age-related eye diseases.

RESULTS

Our search yielded 1731 articles, of which 14, 10, 16 and 8 articles met our eligibility criteria for cataract, glaucoma, AMD and DR, respectively. BMI-defined obesity was positively associated with incident cataract, incident AMD and incident DR in Western populations, but in Asian populations associations for incident AMD were not significant and associations for incident DR were inverse. WC-defined obesity was associated with incident glaucoma in non-Western populations. WHR-defined obesity but not BMI-defined obesity was associated with the incidence or progression of AMD in two Western studies.

CONCLUSIONS

Overall, we found strong evidence supporting associations between obesity and age-related eye diseases. Further research on the association of abdominal obesity and effect of weight loss and physical activity on age-related eye diseases is warranted to support clinical and public health recommendations.

An association of neovascular age-related macular degeneration with polymorphisms of CFH, ARMS2, HTRA1 and C3 genes in Czech population

PURPOSE

We investigated associations between neovascular age-related macular degeneration (AMD) and rs10490924 polymorphism of ARMS2 gene (age-related maculopathy susceptibility 2), rs1061170 polymorphism of gene for complement factor H (CFH), rs2230199 polymorphism of gene for complement component C3 and rs11200638 polymorphism of gene for serine protease high-temperature requirement A1 (HTRA1) in the Czech population.

METHODS

We analysed samples of DNA from 307 patients diagnosed with neovascular form of late AMD (average age: 73.7 ± 7.7 years) and 191 control subjects, recruited from patients awaiting cataract surgery (average age, 73.6 ± 8.7 years).

RESULTS

HTRA1, CFH and ARMS2 genes polymorphisms were found to be related to neovascular AMD in the Czech population. All analysed polymorphisms were statistically significantly associated with neovascular AMD, with stronger associations in females than in males. In whole group, CC genotype of CFH gene polymorphism, TT genotype of ARMS2 gene polymorphism and AA genotype of HTRA1 gene polymorphism showed the greatest risk for neovascular AMD with odds ratios equal to 8.43, 10.07, 9.83, respectively (p < 0.0001). Only CG polymorphism of C3 gene showed statistically significant risk for neovascular AMD. In addition, we observed an association between waist circumference and neovascular AMD in both sexes, which further suggests the significance of excessive abdominal fat as a risk factor of AMD. We found a statistically significant association between polymorphisms in HTRA1, CFH and ARMS2 genes and neovascular AMS in the Czech population. The association was stronger in females than in males.

CONCLUSION

We demonstrated a relationship between neovascular AMD and genes for HTRA1, CFH, ARMS2 and C3 in Czech population. To our knowledge, the relationship between these polymorphisms and neovascular AMD in Czech population has never been investigated before.

An Open-Label Pilot Study on Macumax Supplementation for Dry-Type Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is one of the most widespread degenerative disorders in elderly people. A 90-day, open-label clinical study was conducted in 40 patients, aged 50 years or older, with early-stage dry-type AMD to evaluate the safety and efficacy of Macumax^®, a novel mixture of a phyto-mineral nutritional supplement containing ZeaLutein^® (consisting of lutein, zeaxanthin, and piperine), extracts of bilberry, saffron, and zinc monomethionine. Subjects received one capsule of the supplement twice daily for 90 days. The treatment measures included physical examination, vital signs, and assessment of subjective and objective symptoms at baseline and after treatment. For efficacy assessment, baseline values were compared with the values after treatment at 30-day intervals, on days 30, 60, and 90. The safety of the treatment was assessed during all the visits. Overall, the patients showed improvement in the subjective symptoms, such as vision scores after treatment compared with baseline. The changes in diminished and distorted vision scores were found to be significant from day 60 (P < .05). In the case of objective symptoms, only 40% of the subjects (P < .05) had abnormal Amsler's grid aberration scores on day 90 compared with 77.5% of subjects at the beginning of the study. No adverse events were observed during the study. This pilot study provides evidence that Macumax^® supplementation is safe and maintained eye health without further progression of the disease in patients with early-stage dry-type AMD. Clinical Trial Registration number: CTRI/2016/02/006676

Adult body height and age-related macular degeneration in healthy individuals: A nationwide population-based survey from Korea

We sought to evaluate the relationship between adult body height and risk of age-related macular degeneration (AMD) among healthy Koreans using nationwide population-based data. We analyzed data derived from the Korea National Health and Nutrition Examination Survey 2008–2011. Participants over 40 years of age were included in the sample after excluding individuals with systemic comorbidities or missing relevant data. The presence and severity of AMD were graded using fundus photographs. The relationship between body height and risk of AMD was determined using multiple logistic regression analyses. Among a total of 8,435 participants, 544 (6.45%) had AMD: 502 (5.95%) with early AMD and 42 (0.5%) with late AMD. In multivariate-adjusted analyses, taller body height was significantly associated with a lower prevalence of AMD (odds ratio [OR], 0.89; 95% confidence interval [CI], 0.81–0.99), while body mass index (BMI) was not associated with AMD. An inverse association between body height and risk of AMD was observed most frequently in participants under 65 years of age (OR, 0.81; 95% CI, 0.70–0.94). Furthermore, body height showed an inverse association with risk of AMD among obese participants (BMI ≥25.0 kg/m²) (OR, 0.75; 95% CI, 0.60–0.93). Subgroup analysis by AMD type disclosed a significant inverse association between body height and early AMD (OR, 0.87; 95% CI, 0.79–0.97) but not late AMD. Our results suggest that shorter body height is independently associated with increased risk of AMD, especially early AMD, in a dose-response manner in people who are obese or under 65 years of age.

Ophthalmologic evaluation of severely obese patients undergoing bariatric surgery: A pilot, monocentric, prospective, open-label study

Purpose

The aim of this study was to investigate the pathogenic role of obesity on blinding eye diseases in a population of severely obese patients with no history of eye diseases, and to verify whether weight loss induced by bariatric surgery may have a protective effect.

Methods

This was a pilot, monocentric, prospective, and open label study conducted at the University Hospital of Pisa. Fifty-seven severely obese patients with a mean body mass index value of 44.1 ± 6 kg/m² were consecutively recruited and received a complete ophthalmological evaluation and optical coherence tomography. Twenty-nine patients who underwent gastric bypass were evaluated also 3 months, and 1 year after surgery.

Results

At baseline, blood pressure value were directly and significantly related to intraocular pressure values (p<0.05, R = 0.35). Blood pressure values were also significantly and inversely related to retinal nerve fiber layer thickness, particularly in the temporal sector (RE p<0.05 r-0.30; LE p<0.01, R = -0.43). Moreover, minimum foveal thickness values were significantly and inversely associated with body mass index (RE p<0.02, R = -0.40; LE p<0.02, R = -0.30). A significant reduction of body mass index (p<0.05) and a significant (p<0.05) improvement of blood pressure was observed three months and one year after gastric bypass, which were significantly associated with an increase in retinal nerve fiber layer thickness and minimum foveal thickness values in both eyes (p<0.05).

Conclusions

The results of this study suggest that obese patients may have a greater susceptibility to develop glaucomatous optic nerve head damage and age-related macular degeneration. Moreover, weight reduction and improvement of comorbidities obtained by bariatric surgery may be effective in preventing eye disease development by improving retinal nerve fiber layer and foveal thickness.

Prevalence of visual impairment and related factors in Nangarhar Province of Afghanistan: a cross sectional study

AIM

To determine the prevalence, main causes, and related factors of visual impairment (VI) among people aged 50y and over in Jalalabad City and four surrounding districts of Nangarhar Province of Afghanistan.

METHODS

The data for the population based cross-sectional study was collected in 2015. The calculated sample size was 1353, allocated to urban-rural strata using probability proportion to size method. At the end of the study, 1281 people participated in to the study. VI was defined as presenting visual acuity (VA) of less than 6/18 and blindness as VA less than 3/60 in the better eye by using Snellen chart only. Data was analyzed using IBM SPSS 21.0 software.

RESULTS

The prevalence of VI was 22.6% (95%CI, 20%-25%) of which 13.9% (95%CI, 12%-16%) was low vision and 8.7% (95%CI, 7%-10%) was blindness. The most common causes of the VI were cataract (52.8%), followed by uncorrected refractive error (URE) (26.9%) and glaucoma (8.6%). Number one cause of the low vision was URE (42%), followed by cataract, glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy (DR), while for blindness they are cataract (72%), other posterior segment disorders, glaucoma, URE and AMD. Illiteracy, bad economic status, hypertension and overweight were factors independently associated with both VI and low vision, whereas, age, illiteracy, bad economic status, hypertension and using of sunglasses were independently associated with blindness.

CONCLUSION

Cataract, URE, glaucoma, AMD and DR are the leading causes of VI and blindness in the study area. They are mostly avoidable. In order to decrease the burden of VI and blindness in the study area as well as the whole country, it is strongly recommended to apply the prevention policies of VI and blindness.

Glucose & energy homeostasis: Lessons from animal studies

Glucose in our body is maintained within a narrow range by the humoral control and a 'lipostat' system regulated by leptin from adipose tissues, which keep our accumulated fat stores in check. Any disturbance in this delicately poised homeostasis could be disastrous as it can lead to obesity and its associated metabolic manifestations. Laboratory animals, especially rodents, have contributed to our knowledge in understanding this physiological mechanism through an array of genetic and non-genetic animals developed over the years. Two rat mutant obese models-Wistar inbred at National Institute of Nutrition (WNIN)/Ob-obese rats with normal glucose levels and WNIN/GR-Ob-obese with impaired glucose tolerance were developed in the National Centre for Laboratory Animal Sciences (Now ICMR-National Animal Resource Facility for Biomedical Research) at Hyderabad, India. These animals are unique, as, unlike the earlier models, they show all types of degenerative disorders associated with obesity, within a single system. Thus they show impairment in all the major organs of the body - liver, pancreas, kidney, bones, muscles, gonads, brain, eyes, and are sensitive to diet manipulations, have compromised immunity, often develop tumours and have reduced life span. One may argue that there are limitations to one's interpretations from animal studies to human application, but then one cannot shut one's eyes to the new lessons they have taught us in modifying our life styles.

Association of obesity and age-related macular degeneration in Indian population

Purpose:

The aim of this study was to establish the prevalence and association of age-related macular degeneration (AMD) and obesity which was not studied extensively in Indian population over 60 years of age.

Methods:

This was a cross-sectional, population-based study. A total of 4791 patients with gradable fundus photography were included. All patients underwent detailed ophthalmic examination and AMD was graded with retinal photographs. Grading of AMD was done according to the International ARM Epidemiological Study Group and staged based on grading in worse eye. The association of AMD severity and obesity (based on body mass index, waist–hip ratio, waist circumference, isolated abdominal obesity, isolated generalized obesity, and combined obesity) was assessed. The main outcome variable was an association between the presence and severity of AMD with different grades of obesity.

Results:

No direct significant association was noted between the presence and severity of AMD and any obesity indices. Subgroup analyses based on lifestyle patterns and common systemic pathologies in AMD population were done. Late AMD was significantly associated with tobacco consumption in population with combined obesity (P = 0.033 and odds ratio = 2.998).

Conclusion:

No direct association was noted between the presence or severity of AMD and obesity in South Indian population. However, indirect associations between the severity of AMD and combined obesity were found.

Six-Year Incidence and Risk Factors of Age-Related Macular Degeneration in Singaporean Indians: The Singapore Indian Eye Study

We aimed to determine the 6-year incidence and risk factors of age-related macular degeneration (AMD) in first and second generations of Singaporean Indians. Baseline examination was conducted in 2007-9 and 6-year propsective follow-up examination of this Indian population in 2013-5. All participants underwent interviews with questionnaires and comprehensive medical and eye examinations. Incidence was age-standardized to Singaporean 2010 census. Risk factors associated with AMD incidence were assessed and compared between first and second generations of immigrants. Among 2200 persons who participated in the follow-up examination (75.5% response rate), gradable fundus photographs were available in 2105. The 6-year age-standardized incidences of early and late AMD were 5.26% and 0.51% respectively. Incident early AMD was associated with cardiovascular disease history (HR 1.59, 95% CI 1.04-2.45), underweight body mass index (BMI) (HR 3.12, 95% CI 1.37-7.14) (BMI of <18.5 vs 18.51-25 kg/m2), heavy alcohol drinking (HR 3.14 95% CI 1.25-7.89) and ARMS2 rs3750847 homozygous genetic loci carrier (HR 2.52, 95% CI 1.59-3.99). We found a relatively low incidence of early AMD in this Singaporean Indian population compared to Caucasian populations. Both first and second-generation Indian immigrants have similar incidence and risk factor patterns for early AMD.

Obesity-induced metabolic disturbance drives oxidative stress and complement activation in the retinal environment

Purpose

Systemic increases in reactive oxygen species, and their association with inflammation, have been proposed as an underlying mechanism linking obesity and age-related macular degeneration (AMD). Studies have found increased levels of oxidative stress biomarkers and inflammatory cytokines in obese individuals; however, the correlation between obesity and retinal inflammation has yet to be assessed. We used the leptin-deficient (ob/ob) mouse to further our understanding of the contribution of obesity to retinal oxidative stress and inflammation.

Methods

Retinas from ob/ob mice were compared to age-matched wild-type controls for retinal function (electroretinography) and gene expression analysis of retinal stress (Gfap), oxidative stress (Gpx3 and Hmox1), and complement activation (C3, C2, Cfb, and Cfh). Oxidative stress was further quantified using a reactive oxygen species and reactive nitrogen species (ROS and RNS) assay. Retinal microglia and macrophage migration to the outer retina and complement activation were determined using immunohistochemistry for IBA1 and C3, respectively. Retinas and sera were used for metabolomic analysis using QTRAP mass spectrometry.

Results

Retinal function was reduced in ob/ob mice, which correlated to changes in markers of retinal stress, oxidative stress, and inflammation. An increase in C3-expressing microglia and macrophages was detected in the outer retinas of the ob/ob mice, while gene expression studies showed increases in the complement activators (C2 and Cfb) and a decrease in a complement regulator (Cfh). The expression of several metabolites were altered in the ob/ob mice compared to the controls, with changes in polyunsaturated fatty acids (PUFAs) and branched-chain amino acids (BCAAs) detected.

Conclusions

The results of this study indicate that oxidative stress, inflammation, complement activation, and lipid metabolites in the retinal environment are linked with obesity in ob/ob animals. Understanding the interplay between these components in the retina in obesity will help inform risk factor analysis for acquired retinal degenerations, including AMD.

Lutein and zeaxanthin isomers modulates lipid metabolism and the inflammatory state of retina in obesity-induced high-fat diet rodent model

Background

Several studies associated high-fat intakes with a high incidence of age-related macular degeneration (AMD). Lutein and Zeaxanthin isomers (L/Zi) may counteract reactive oxygen species produced by oxidative stress. The present study was conducted to determine the possible effects of L/Zi administration on lipid profile, protein genes associated with oxidative stress and inflammation pathways in the obesity induced by a high-fat diet (HFD) in rodents.

Methods

Twenty-eight male Wistar rats were allocated into four groups as follows: (i) Control, (ii) Control + L/Zi, (iii) High Fat Diet (HFD), and (iv) HFD+ L/Z. L/Zi was administrated for 8 weeks at a daily dose of 100 mg/kg BW.

Results

L/Zi administration significantly reduced insulin and free fatty acid (FFA) levels (P < 0.001) and ameliorated the oxidative damage by reducing malondialdehyde (MDA) concentration and increasing antioxidant enzymes activities of retina induced by HFD. In addition, supplementation decreased the levels of vascular endothelial growth factor (VEGF), inducible nitric oxide synthase (iNOS), nuclear factor-kappa B (NF-κB) and intercellular adhesion molecule-1 (ICAM) (P < 0.001, respectively) and improved nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) gene proteins in retinal tissues (P < 0.001).

Conclusion

Rats fed with HFD exhibited increased oxidative stress and upregulation of inflammatory indicators. However, L/Zi supplementation modulates genes involved oxidative stress and inflammation including NF-κB and Nrf2 signaling pathways in the retina which may contribute to ameliorating retinal damage induced by HFD.

Risk factors and biomarkers of age-related macular degeneration

A biomarker can be a substance or structure measured in body parts, fluids or products that can affect or predict disease incidence. As age-related macular degeneration (AMD) is the leading cause of blindness in the developed world, much research and effort has been invested in the identification of different biomarkers to predict disease incidence, identify at risk individuals, elucidate causative pathophysiological etiologies, guide screening, monitoring and treatment parameters, and predict disease outcomes. To date, a host of genetic, environmental, proteomic, and cellular targets have been identified as both risk factors and potential biomarkers for AMD. Despite this, their use has been confined to research settings and has not yet crossed into the clinical arena. A greater understanding of these factors and their use as potential biomarkers for AMD can guide future research and clinical practice. This article will discuss known risk factors and novel, potential biomarkers of AMD in addition to their application in both academic and clinical settings.

Factors Associated With Poor Response to Aflibercept After Switching From Ranibizumab or Bevacizumab in Neovascular Age-related Macular Degeneration

BACKGROUND AND OBJECTIVE

The purpose of this study was to analyze demographic and ocular features of patients with age-related macular degeneration who failed aflibercept (Eylea; Regeneron, Tarrytown, NY) treatment after switching from ranibizumab (Lucentis; Genentech, South San Francisco, CA) or bevacizumab (Avastin; Genentech, South San Francisco, CA).

PATIENTS AND METHODS

Retrospective chart review of patients treated with aflibercept at the Byers Eye Institute from November 2011 to August 2014. Patient visual acuity was noted prior to aflibercept; after 1, 3, and 12 months; and on the most recent visit. Patients who improved vision after switching were compared to patients who lost vision. Demographic and imaging features were analyzed using univariate and multivariate statistics.

RESULTS

Patients who lost vision had significantly higher BMI (P = .013, multivariate) and geographic atrophy (P = .0381, univariate; P = .1, multivariate) compared to patients who improved vision.

CONCLUSION

BMI and geographic atrophy may be considered as potential indicators for poor response to aflibercept after switching from ranibizumab or bevacizumab. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:458-465.].

Genetic Association Analysis of Drusen Progression

PURPOSE

Age-related macular degeneration is a common form of vision loss affecting older adults. The etiology of AMD is multifactorial and is influenced by environmental and genetic risk factors. In this study, we examine how 19 common risk variants contribute to drusen progression, a hallmark of AMD pathogenesis.

METHODS

Exome chip data was made available through the International AMD Genomics Consortium (IAMDGC). Drusen quantification was carried out with color fundus photographs using an automated drusen detection and quantification algorithm. A genetic risk score (GRS) was calculated per subject by summing risk allele counts at 19 common genetic risk variants weighted by their respective effect sizes. Pathway analysis of drusen progression was carried out with the software package Pathway Analysis by Randomization Incorporating Structure.

RESULTS

We observed significant correlation with drusen baseline area and the GRS in the age-related eye disease study (AREDS) dataset (ρ = 0.175, P = 0.006). Measures of association were not statistically significant between drusen progression and the GRS (P = 0.54). Pathway analysis revealed the cell adhesion molecules pathway as the most highly significant pathway associated with drusen progression (corrected P = 0.02).

CONCLUSIONS

In this study, we explored the potential influence of known common AMD genetic risk factors on drusen progression. Our results from the GRS analysis showed association of increasing genetic burden (from 19 AMD associated loci) to baseline drusen load but not drusen progression in the AREDS dataset while pathway analysis suggests additional genetic contributors to AMD risk.

Impact of visceral fat and pro-inflammatory factors on the pathogenesis of age-related macular degeneration

PURPOSE

Previous studies have indicated that the immune system is involved in the pathogenesis of the AMD. Increased visceral fat, in addition, has a pro-inflammatory effect on the organism by producing or influencing different kinds of inflammatory factors. The aim of this study is to determine the relationship of body fat distribution in patients with age-related macula degeneration in comparison to a control group in the Austrian population.

METHODS

In this case-control study, body weight and height, and body mass index (BMI) were measured for each subject in 54 patients with exudative AMD and compared to 46 gender- and age-matched healthy control subjects. Body composition and abdominal fat areas were measured using dual-energy X-ray absorptiometry (DEXA). Data on age, gender distribution, smoking history and systemic diseases, respectively, were compared. The inflammatory markers CRP, tumour necrosis factor-alpha (TNF-alpha), leptin, amyloid A, amyloid beta and interleukin-6 (IL-6) were assayed by ELISA (R&D).

RESULTS

DEXA revealed central-abdominal-to-total body fat ratio of 0.073 +/- 0.011 in AMD patients compared to 0.061 +/- 0.013 in the controls (p <0.001; d = 0.98). The calculation of BMI has provided a significant result (p =0.045). U-test results for Aß1-42, IL-6, SAA and CRP each were significant (p < 0.05), with higher values in AMD patients. Leptin, TNF-alpha and Aß1-40 showed no significant differences between the groups.

CONCLUSION

Our results suggest that abdominal fat distribution is significantly associated with age-related macular degeneration. Analysis of patients with exudative AMD revealed higher levels of CRP, amyloid ß1-42, IL-6 and amyloid alpha.

Cardiovascular risk factors associated with age-related macular degeneration: the Tromsø Study

PURPOSE

To examine associations between cardiovascular risk factors and age-related macular degeneration (AMD).

METHODS

A population-based, cross-sectional study of Caucasians aged 65-87 years was conducted in Norway in 2007/2008. Retinal photographs were graded for AMD. Multivariable logistic regression analyses were performed based on questionnaires addressing habits of smoking, alcohol consumption, physical activity, health and medication; and physical examination comprising anthropometric measurements, blood pressure and blood sampling. Cardiovascular disease status was obtained from a validated end-point registry.

RESULTS

Gradable photographs were available for 2631 participants, of whom 92 (3.5%) subjects had late AMD. In the multivariable analysis of late AMD, significant interactions were found between sex and the variables age, triglyceride level, use of lipid-lowering drugs and physical exercise. Current daily smoking was significantly related to late AMD in both sexes (odds ratio (OR) 4.06, 95% confidence interval (CI) 1.69-9.76 and OR 3.59, 95% CI 1.17-11.04, women and men, respectively) compared with never smokers. Higher number of pack years was associated with the presence of large drusen (>125 μm) (OR 1.04, 95% CI 1.01-1.09 per 5 years). Higher systolic blood pressure (OR 1.06, 95% CI 1.01-1.12 per 5 mmHg), overweight (OR 2.87, 95% CI 1.13-7.29) and obesity (OR 2.92, 95% CI 1.06-8.03), physical exercise duration (OR 0.41, 95% 0.18-0.96 for 30 min or more compared with less) and frequency (OR 0.46, 95% CI 0.23-0.92 for weekly or more often compared to less) were associated with late AMD in women only.

CONCLUSIONS

Smoking was strongly associated with AMD, in line with results from other populations. Also, late AMD was related to higher systolic blood pressure, physical inactivity, overweight and obesity in women.

Iris color and associated pathological ocular complications: a review of epidemiologic studies

AIM

To elucidate the associations of iris color with major eye diseases.

METHODS

A systematic search on Medline with coverage up to August 2013 was conducted. Assessment of the quality of studies based on their levels of evidence was in accordance with the Centre for Evidence-Based Medicine, Oxford, United Kingdom.

RESULTS

A relationship between darker iris color and an increased risk of age-related cataract has been reported from cross-sectional studies and prospective cohort studies. There was no consistent evidence supporting a major role of iris color in the development or progression of age-related macular degeneration. The association of iris color with ocular uveal melanoma has been confirmed by a meta-analysis of observational studies previously. The etiologic synergism between light iris color and environmental exposure such as UV the exposure of UV radiation was found. There were no studies evaluating the refractive associations with iris color but there may be a possible link between iris color and myopia.

CONCLUSION

Darker iris color is associated with an increased risk of cataract and a reduced risk of ocular uveal melanoma. The association of iris color with age-related macular degeneration is not confirmed. Ophthalmologists should be aware that the risk of ocular disorders appears to vary by differences in iris color.

Relationship between Body Mass Index, Blood Pressure, and Visual Acuity in Residents of Esan West Local Government Area of Edo State, Nigeria

Aim. To study the relationship between body mass index (BMI) and blood pressure (BP) on visual acuity among apparently healthy residents of Ekpoma, Esan West Local Government Area of Edo State, Nigeria. Methodology. This is a cross-sectional descriptive study among 225 subjects (ages of 18–35 years) from whom BP, body weight, and height were collected. Visual acuity was measured using the Snellen chart following standard procedures of number of letters seen at 6-metre distance. The data were then analyzed using SPSS version 17. Results. The sampled population consists of 112 male and 113 female (mean age 31.72±14.2 years). Majority (180) of the respondents had normal visual acuity. However, compared with the respondents with normal BMI (R19.61±1.5; L19.67±1.70), visual acuity of underweight (R18.53±2.30; L18.53±2.70) and obese (R15.68±4.79; L17.73±1.70) were more deviated. Similarly, compared with respondent with normal BP (120–125/80–85 mmHg; R18.00±2.53; L18.07±3.11), hypotensive (R15.5±7.35; L15.00±10.20), and hypertensive (R15.01±21.25; L15.00±11.91) respondents had deviated visual acuity. Conclusion. Abnormal body weight (underweight and obese) and BP (hypotension and hypertension) have potential negative impacts on visual acuity. Based on the observed relationship between weights, BP, and visual acuity, eye examinations can be included as regular screening exercise for abnormal BMI and BP conditions.

Rare complement factor H variant associated with age-related macular degeneration in the Amish

PURPOSE

Age-related macular degeneration is the leading cause of blindness among the adult population in the developed world. To further the understanding of this disease, we have studied the genetically isolated Amish population of Ohio and Indiana.

METHODS

Cumulative genetic risk scores were calculated using the 19 known allelic associations. Exome sequencing was performed in three members of a small Amish family with AMD who lacked the common risk alleles in complement factor H (CFH) and ARMS2/HTRA1. Follow-up genotyping and association analysis was performed in a cohort of 973 Amish individuals, including 95 with self-reported AMD.

RESULTS

The cumulative genetic risk score analysis generated a mean genetic risk score of 1.12 (95% confidence interval [CI]: 1.10, 1.13) in the Amish controls and 1.18 (95% CI: 1.13, 1.22) in the Amish cases. This mean difference in genetic risk scores is statistically significant (P = 0.0042). Exome sequencing identified a rare variant (P503A) in CFH. Association analysis in the remainder of the Amish sample revealed that the P503A variant is significantly associated with AMD (P = 9.27 × 10(-13)). Variant P503A was absent when evaluated in a cohort of 791 elderly non-Amish controls, and 1456 non-Amish cases.

CONCLUSIONS

Data from the cumulative genetic risk score analysis suggests that the variants reported by the AMDGene consortium account for a smaller genetic burden of disease in the Amish compared with the non-Amish Caucasian population. Using exome sequencing data, we identified a novel missense mutation that is shared among a densely affected nuclear Amish family and located in a gene that has been previously implicated in AMD risk.

Nature and nurture- genes and environment- predict onset and progression of macular degeneration

Age-related macular degeneration (AMD) is a common cause of irreversible visual loss and the disease burden is rising world-wide as the population ages. Both environmental and genetic factors contribute to the development of this disease. Among environmental factors, smoking, obesity and dietary factors including antioxidants and dietary fat intake influence onset and progression of AMD. There are also several lines of evidence that link cardiovascular, immune and inflammatory biomarkers to AMD. The genetic etiology of AMD has been and continues to be an intense and fruitful area of investigation. Genome-wide association studies have revealed numerous common variants associated with AMD and sequencing is increasing our knowledge of how rare genetic variants strongly impact disease. Evidence for interactions between environmental, therapeutic and genetic factors is emerging and elucidating the mechanisms of this interplay remains a major challenge in the field. Genotype-phenotype associations are evolving. The knowledge of non-genetic, modifiable risk factors along with information about heritability and genetic risk variants for this disease acquired over the past 25 years have greatly improved patient management and our ability to predict which patients will develop or progress to advanced forms of AMD. Personalized medicine and individualized prevention and treatment strategies may become a reality in the near future.

C-reactive protein and the incidence of macular degeneration: pooled analysis of 5 cohorts

IMPORTANCE

This study adds to the evidence that elevated levels of high-sensitivity C-reactive protein (hsCRP) predict future risk of age-related macular degeneration (AMD). This information might shed light on underlying pathological mechanisms involving inflammation and could be of clinical utility in the identification of persons at high risk of AMD who may benefit from increased adherence to lifestyle recommendations, eye examination schedules, and therapeutic protocols.

OBJECTIVE

To investigate the relationship between hsCRP and future risk of AMD in US men and women.

DESIGN

Pooled analysis of prospective nested case-control data from the Women's Health Study and 4 other cohorts, the Physicians' Health Study, Women's Antioxidant and Folic Acid Cardiovascular Study, Nurses' Health Study, and Health Professionals Follow-up Study.

SETTING

A prospective nested case-control study within 5 large cohorts.

PARTICIPANTS

Patients were initially free of AMD. We prospectively identified 647 incident cases of AMD and selected age- and sex-matched controls for each AMD case (2 controls for each case with dry AMD or 3 controls for each case of neovascular AMD). MAIN OUTCOME MEASURES We measured hsCRP in baseline blood samples. We used conditional logistic regression models to examine the relationship between hsCRP and AMD and pooled findings using meta-analytic techniques.

RESULTS

After adjusting for cigarette smoking status, participants with high (>3 mg/L) compared with low (<1 mg/L) hsCRP levels had cohort-specific odds ratios (ORs) for incident AMD ranging from 0.94 (95% CI, 0.58-1.51) in the Physicians' Health Study to 2.59 (95% CI, 0.58-11.67) in the Women's Antioxidant and Folic Acid Cardiovascular Study. After testing for heterogeneity between studies (Q = 5.61; P = .23), we pooled findings across cohorts and observed a significantly increased risk of incident AMD for high vs low hsCRP levels (OR, 1.49; 95% CI, 1.06-2.08). Risk of neovascular AMD was also increased among those with high hsCRP levels (OR, 1.84; 95% CI, 1.14-2.98).

CONCLUSIONS AND RELEVANCE

Overall, these pooled findings from 5 prospective cohorts add further evidence that elevated levels of hsCRP predict greater future risk of AMD. This information might shed light on underlying mechanisms and could be of clinical utility in the identification of persons at high risk of AMD who may benefit from increased adherence to lifestyle recommendations, eye examination schedules, and therapeutic protocols.

Aspirin use and risk of age-related macular degeneration: a meta-analysis

Background

Age-related macular degeneration (AMD) is the main cause of blindness and the curative options are limited. The objective of this meta-analysis was to determine the association between aspirin use and risk of AMD.

Methods

A comprehensive literature search was performed in PubMed, Embase, Web of Science, and reference lists. A meta-analysis was performed by STATA software.

Results

Ten studies involving 171729 individuals examining the association between aspirin use and risk of AMD were included. Among the included studies, 2 were randomized-controlled trials (RCTs), 4 were case-control studies and 4 were cohort studies. The relative risks (RRs) were pooled using a random-effects model. Relative risks with 95% confidence intervals (CIs) of aspirin use as a risk for AMD. The pooled RR of 10 included studies between the use of aspirin and risk of AMD was 1.09 (95% CI, 0.96–1.24). The same result was detected in early and late stage AMD subgroup analysis. In the subgroup analyses, the pooled RR of RCTs, case-control studies and cohort studies were 0.81 (95% CI, 0.64–1.02), 1.02 (95% CI, 0.92–1.14) and 1.08 (95% CI, 0.91–1.28), respectively.

Conclusions

The use of aspirin was not associated with the risk of AMD.

Vitamin A supplementation ameliorates obesity-associated retinal degeneration in WNIN/Ob rats

OBJECTIVE

Obesity is associated with various health afflictions, including ocular complications such as diabetic retinopathy, high intraocular pressure, cataracts, and macular degeneration. We previously reported progressive retinal degeneration after the onset of obesity in the spontaneously obese rat (WNIN/Ob) model. In the present study, we investigated vitamin A supplementation to ameliorate obesity-associated retinal degeneration in the WNIN/Ob rat.

METHODS

Five-month-old male WNIN/Ob obese (O) and lean (L) control rats were fed with vitamin A 2.6 mg (L/O-I), 26 mg (L/O-II), 52 mg (L/O-III), and 129 mg (L/O-IV) per kilogram of diet as retinyl palmitate for 4 mo 2 wk. Retinal morphology and retinal gene expression were assessed by histologic, immunohistochemical, and real-time polymerase chain reaction methods.

RESULTS

Supplementation of vitamin A at 26 or 52 mg significantly modulated the expression of retinal genes in the O but not in the L phenotype. Vitamin A supplementation significantly upregulated the expression of genes, such as rhodopsin, rod arrestin, phosphodiesterase, transducins, and fatty acid elongase-4, that were otherwise downregulated in O rat retina. The expression of glial fibrillary acidic protein was downregulated by vitamin A feeding in O rat retina. The immunohistochemical and histologic findings corroborated the gene expression data. The effects were significant at a 26- or 52-mg dose of vitamin A.

CONCLUSION

Vitamin A supplementation alleviated obesity-associated retinal degeneration in the WNIN/Ob rat.

Association analysis of genetic and environmental risk factors in the cuticular drusen subtype of age-related macular degeneration

PURPOSE

To assess the association of gender, cigarette smoking, body-mass index, and nine genetic risk variants with cuticular drusen (CD), a well recognized subtype of age-related macular degeneration (AMD).

METHODS

A total of 757 patients with AMD, including 217 patients with CD, and 553 control individuals were interviewed with a questionnaire and underwent an ophthalmic examination. Venous blood samples were obtained for genomic DNA extraction, and genotyping was performed of single nucleotide polymorphisms previously associated with AMD. Odds ratios were calculated for patients with CD, using unaffected control individuals as a reference. Furthermore, odds ratios in patients with CD were compared to those in patients with "non-CD" AMD.

RESULTS

The CD subtype of AMD was significantly associated with current smoking as well as variants in the complement factor H (CFH), age-related maculopathy susceptibility 2 (ARMS2), complement factor B/complement component 2 (CFB/C2), complement component 3 (C3), and apolipoprotein E (APOE) genes. In patients with CD, the association with the CFH Y402H risk allele was significantly higher (p=0.022), whereas the association with current smoking was significantly lower (p<0.001) than in the heterogeneous group of patients with "non-CD" AMD.

CONCLUSIONS

The AMD subtype of CD was associated with previously identified genetic AMD risk factors. However, the association with the CFH Y402H risk allele appeared to be stronger, whereas the association with smoking was less pronounced when compared to AMD as a whole. This study suggests a more important role for genetic factors than environmental factors in the development of this well defined subtype of AMD. These findings stress the importance of detailed phenotyping in AMD to identify homogeneous AMD subtypes, which may be associated with different risk factors and disease mechanisms. Such studies will improve the accuracy of predictive models and the effectiveness of preventive and therapeutic options in AMD.

Dry age-related macular degeneration: A currently unmet clinical need

Age-related macular degeneration (AMD) is a leading cause of severe visual impairment and disability in older people worldwide. Although considerable advances in the management of the neovascular form of AMD have been made in the last decade, no therapy is yet available for the advanced dry form of AMD (geographic atrophy). This review focuses on current trends in the development of new therapies targeting specific pathophysiological pathways of dry AMD. Increased understanding of the complex mechanisms that underlie dry AMD will help to address this largely unmet clinical need.

Lipids, lipoproteins, and age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness among the elderly. While excellent treatment has emerged for neovascular disease, treatment for early AMD is lacking due to an incomplete understanding of the early molecular events. A prominent age-related change is the accumulation of neutral lipid in normal Bruch's membrane (BrM) throughout adulthood and also disease-related BrM accumulations called basal deposits and drusen. AMD lesion formation has thus been conceptualized as sharing mechanisms with atherosclerotic plaque formation, where low-density lipoprotein (LDL) retention within the arterial wall initiates a cascade of pathologic events. However, we do not yet understand how lipoproteins contribute to AMD. This paper explores how systemic and local production of lipoproteins might contribute to the pathogenesis of AMD.

Abdominal obesity and age-related macular degeneration

Evidence for an association between age-related macular degeneration (AMD) and obesity is inconsistent. The authors examined associations between adiposity and AMD prevalence using 21,287 participants from the Melbourne Collaborative Cohort Study aged 40-69 years at baseline (1990-1994). For men, each increase of 0.1 in waist/hip ratio (~1 standard deviation) was associated with a 13% increase in the odds of early AMD (odds ratio = 1.13, 95% confidence interval: 1.01, 1.26; P = 0.03) and a 75% increase in the odds of late AMD (odds ratio = 1.75, 95% confidence interval: 1.11, 2.76; P = 0.02). No other adiposity measure was associated with early AMD for men. Smoking status modified the relation between waist/hip ratio and early AMD (P = 0.05), with no association for former smokers. For women, there were inverse associations with early AMD for all adiposity measures (odds ratios = 0.89-0.93; P = 0.002-0.02), but no associations were observed for late AMD. This study confirms abdominal obesity as an AMD risk factor for men despite a survivorship effect from competing risks in morbidity and mortality. The inverse associations for women may reflect weaker true positive associations with AMD that are insufficient to overcome the survivorship effect. New data are provided on complex interactions between environmental exposures and AMD risk.

Impact of AREDS in a developing country 5 years after publication of the study

PURPOSE

The Age-Related Eye Disease Study (AREDS) is the only large-scale study to demonstrate a reduction in the risk of progression to end-stage age-related macular degeneration (AMD) when vitamin supplementation was given to patients with advanced forms of the disease. Our study assesses the impact of this study on vitamin supplementation in patients with advanced AMD from 5 years before publication of the AREDS results until 5 years after.

METHODS

Medical records of patients with AMD presenting between September 1996 and October 2006 were reviewed. Patients were subclassified according to AREDS categories. The proportion of advanced cases on vitamin replacement before October 2001 was compared to that after October 2001. Since October 2001, the different reasons for abstinence were investigated and analyzed.

RESULTS

Only 2403 patients of the 40,000 medical records reviewed met the AREDS AMD criteria. Of these, 137 patients verifying categories 3 and 4 were diagnosed prior to October 2001. Fourteen were on supplements then. Fifty-three patients complied with the represcribed vitamins during subsequent visits after October 2001, raising the percentage significantly to 48.9% (p<0.001). Also, from October 2001 until October 2006, an additional 76 patients verified categories 3 and 4. Fifty-three (69.7%) of them were on vitamins (p=0.001). Financial burden was the principal reason for abstinence in 67.7% of patients prescribed vitamins after October 2001.

CONCLUSIONS

The results of AREDS had an impressive impact on prescribing supplements in AREDS category 3 and 4 patients in Lebanon. The main reason for noncompliance is financial.

Dietary ω-3 fatty acid and fish intake and incident age-related macular degeneration in women

OBJECTIVE

To examine whether intake of ω-3 fatty acids and fish affects incidence of age-related macular degeneration (AMD) in women.

DESIGN

A detailed food-frequency questionnaire was administered at baseline among 39 876 female health professionals (mean [SD] age: 54.6 [7.0] years). A total of 38 022 women completed the questionnaire and were free of a diagnosis of AMD. The main outcome measure was incident AMD responsible for a reduction in best-corrected visual acuity to 20/30 or worse based on self-report confirmed by medical record review.

RESULTS

A total of 235 cases of AMD, most characterized by some combination of drusen and retinal pigment epithelial changes, were confirmed during an average of 10 years of follow-up. Women in the highest tertile of intake for docosahexaenoic acid, compared with those in the lowest, had a multivariate-adjusted relative risk of AMD of 0.62 (95% confidence interval, 0.44-0.87). For eicosapentaenoic acid, women in the highest tertile of intake had a relative risk of 0.66 (95% confidence interval, 0.48-0.92). Consistent with the findings for docosahexaenoic acid and eicosapentaenoic acid, women who consumed 1 or more servings of fish per week, compared with those who consumed less than 1 serving per month, had a relative risk of AMD of 0.58 (95% confidence interval, 0.38-0.87).

CONCLUSION

These prospective data from a large cohort of female health professionals without a diagnosis of AMD at baseline indicate that regular consumption of docosahexaenoic acid and eicosapentaenoic acid and fish was associated with a significantly decreased risk of incident AMD and may be of benefit in primary prevention of AMD.

Arterial thromboembolic events in patients with exudative age-related macular degeneration treated with intravitreal bevacizumab or ranibizumab

BACKGROUND/AIMS

To compare retrospectively the incidence of arterial thromboembolic events (ATEs) in patients treated with bevacizumab or ranibizumab for exudative age-related macular degeneration.

METHODS

Charts of 378 patients treated with at least 1 intravitreal injection of ranibizumab or bevacizumab were reviewed to calculate the incidence of ATEs. Only patients under monotherapy were analyzed.

RESULTS

ATEs occurred in 15 patients: 12 (12/97) with bevacizumab (12.4%) and 3 (3/219) with ranibizumab (1.4%) - odds ratio 10.16; 95% confidence interval 2.80-36.93; p < 0.0001. ATEs in the bevacizumab and ranibizumab cohorts included stroke, myocardial infarction, angina pectoris, peripheral thromboembolic disease, transient ischemic attack, sudden death and lethal stroke.

CONCLUSION

In this series, bevacizumab raised the risk of ATEs when compared to ranibizumab. In an elderly population with multiple cardiovascular risk factors, the new ATEs may not be attributed exclusively to the intravitreal bevacizumab administration. These findings raise an issue that must be confirmed in randomized clinical trials.

Healthy lifestyles related to subsequent prevalence of age-related macular degeneration

OBJECTIVE

To investigate the relationships between lifestyle behaviors of diet, smoking, and physical activity and the subsequent prevalence of age-related macular degeneration (AMD).

METHODS

The population included 1313 participants (aged 55-74 years) in the Carotenoids in Age-Related Eye Disease Study, an ancillary study of the Women's Health Initiative Observational Study. Scores on a modified 2005 Healthy Eating Index were assigned using responses to a food frequency questionnaire administered at baseline of the Women's Health Initiative Observational Study (1994-1998). Physical activity and lifetime smoking history were queried. An average of 6 years later, stereoscopic fundus photographs were taken to assess the presence and severity of AMD; it was present in 202 women, 94% of whom had early AMD, the primary outcome.

RESULTS

In multivariate models, women whose diets scored in the highest quintile compared with the lowest quintile on the modified 2005 Healthy Eating Index had 46% lower odds for early AMD. Women in the highest quintile compared with those in the lowest quintile for physical activity (in metabolic energy task hours per week) had 54% lower odds for early AMD. Although smoking was not independently associated with AMD on its own, having a combination of 3 healthy behaviors (healthy diet, physical activity, and not smoking) was associated with 71% lower odds for AMD compared with having high-risk scores (P < .001).

CONCLUSION

Modifying lifestyles might reduce risk for early AMD as much as 3-fold, lowering the risk for advanced AMD in a person's lifetime and the social and economic costs of AMD to society.

Clinical risk factors for age-related macular degeneration: a systematic review and meta-analysis

BACKGROUND

Age-related macular degeneration (AMD) is the leading cause of blindness in Western countries. Numerous risk factors have been reported but the evidence and strength of association is variable. We aimed to identify those risk factors with strong levels of evidence which could be easily assessed by physicians or ophthalmologists to implement preventive interventions or address current behaviours.

METHODS

A systematic review identified 18 prospective and cross-sectional studies and 6 case control studies involving 113,780 persons with 17,236 cases of late AMD that included an estimate of the association between late AMD and at least one of 16 pre-selected risk factors. Fixed-effects meta-analyses were conducted for each factor to combine odds ratio (OR) and/or relative risk (RR) outcomes across studies by study design. Overall raw point estimates of each risk factor and associated 95% confidence intervals (CI) were calculated.

RESULTS

Increasing age, current cigarette smoking, previous cataract surgery, and a family history of AMD showed strong and consistent associations with late AMD. Risk factors with moderate and consistent associations were higher body mass index, history of cardiovascular disease, hypertension, and higher plasma fibrinogen. Risk factors with weaker and inconsistent associations were gender, ethnicity, diabetes, iris colour, history of cerebrovascular disease, and serum total and HDL cholesterol and triglyceride levels.

CONCLUSIONS

Smoking, previous cataract surgery and a family history of AMD are consistent risk factors for AMD. Cardiovascular risk factors are also associated with AMD. Knowledge of these risk factors that may be easily assessed by physicians and general ophthalmologists may assist in identification and appropriate referral of persons at risk of AMD.

The rate of myocardial infarction events among patients with age-related macular degeneration: a population-based study

PURPOSE

To examine the association between age-related macular degeneration (AMD) and the risk of myocardial infarctions (MIs) in a large health maintenance organization.

DESIGN

A retrospective cohort study carried out at Maccabi Healthcare Services (MHS).

PARTICIPANTS

A total of 6,546 patients aged ≥65 years who were diagnosed with AMD between April 18 1996 and June 6 2008, and 61,672 non-AMD patients frequency-matched for age and gender.

METHODS

Participants were retrospectively followed to the day of leaving the MHS, to undergoing an MI, or to closure of the study on July 1 2008, whichever came earlier. The relative risk of MI associated with AMD was estimated using the Cox proportional hazard model.

MAIN OUTCOME MEASURES

Incident myocardial infarction events.

RESULTS

During the study period, there were 159 (5.1 per 1,000 person years [PY]) and 2,997 (4.2 per 1,000 PY) MIs respectively in the AMD and non-AMD patient groups. The age- and gender-adjusted hazard ratio (HR) of MI among AMD patients was 1.01 (95%CI: 0.85-1.20). Baseline medical characteristics associated with increased risk of mortality included diabetes mellitus, hypertension, older age, and male gender. The fully adjusted HR associated with AMD was 1.03 (95%CI: 0.87-1.22).

CONCLUSION

Despite the shared risk factors associated with AMD and MIs, we found no increased risk of MI in AMD patients.

Smoking history and the incidence of age-related macular degeneration--results from the Muenster Aging and Retina Study (MARS) cohort and systematic review and meta-analysis of observational longitudinal studies

To compare the association of smoking with age-related macular degeneration (AMD) in the Muenster Aging and Retina Study (MARS) cohort with current evidence. Adjusted risk ratios for incident AMD in MARS were compared with findings of a systematic review and meta-analysis of observational prospective studies. 9.6% of MARS participants progressed to AMD over a median of 30.9 months. In MARS the adjusted risk ratio in current versus never smokers was 3.25 (95% confidence interval [1.50-7.06]), and 1.28 [0.70-2.33] in former smokers versus never smokers. The meta-analysis of previous studies showed a pooled adjusted risk ratio of 2.51 [1.09-5.76] in current versus never smokers. Inclusion of the MARS findings removed between-study heterogeneity and accentuated the pooled adjusted risk ratio for current smokers to 2.75 [1.52-4.98]. Specific analyses in MARS revealed a protective effect for time since smoking cessation in former smokers with an adjusted risk ratio=0.50 [0.29-0.89] per log(year). Current smoking nearly triples AMD incidence, while smoking cessation lowers AMD incidence in a non-linear fashion even in the elderly.

Background comparison of typical age-related macular degeneration and polypoidal choroidal vasculopathy in Japanese patients

OBJECTIVE

To compare background factors of the 2 most dominant subtypes of exudative age-related macular degeneration (AMD) in the Japanese population: typical AMD and polypoidal choroidal vasculopathy (PCV).

DESIGN

Cross-sectional comparison.

PARTICIPANTS

Consecutive patients with typical AMD (n = 89) and PCV (n = 138) for the primary survey. For the secondary survey, the number of participants was extended to include 148 typical AMD and 170 PCV patients. All the patients included in the present study had been followed up at The University of Tokyo Hospital outpatient macular clinic.

METHODS

Background data on gender; age; body mass index; smoking; alcohol consumption; and histories of hypertension, diabetes mellitus (DM), hyperlipidemia, ischemic heart disease, stroke, intensive light exposure, central serous chorioretinopathy (CSC), cataract surgery, glaucoma, and steroid use were obtained mainly through interview. The interviewers were masked to the subtype diagnosis of AMD. Univariate and multivariate logistic regression analyses were performed to identify differences in the background factors between typical AMD and PCV. In the secondary survey, the association of a history of CSC and PCV was confirmed further, and funduscopic findings of an atrophic retinal pigment epithelial (RPE) tract and focal photocoagulation scars that could indicate a history of CSC were investigated.

MAIN OUTCOME MEASURES

Frequency and mean of background factors in patients with typical AMD or PCV.

RESULTS

The 2 groups showed similar backgrounds with the exception of their histories of DM and CSC. A history of DM was more frequent in typical AMD (24.7% vs. 13.0% in the primary survey; P = 0.027), whereas a history of CSC was more prevalent in PCV (3.4% vs. 14.7% in the secondary survey; P = 0.0005). Funduscopic findings of an atrophic RPE tract or focal photocoagulation scars were found more frequently in PCV (0.7% vs. 7.6%; P = 0.002).

CONCLUSIONS

Background factors of typical AMD and PCV are similar but not identical. A history of DM and CSC are more frequent in typical AMD and PCV, respectively.

Risk factors for age-related maculopathy

Age-related maculopathy (ARM) is the leading cause of blindness in the elderly. Although beneficial therapeutic strategies have recently begun to emerge, much remains unclear regarding the etiopathogenesis of this disorder. Epidemiologic studies have enhanced our understanding of ARM, but the data, often conflicting, has led to difficulties with drawing firm conclusions with respect to risk for this condition. As a consequence, we saw a need to assimilate the published findings with respect to risk factors for ARM, through a review of the literature appraising results from published cross-sectional studies, prospective cohort studies, case series, and case control studies investigating risk for this condition. Our review shows that, to date, and across a spectrum of epidemiologic study designs, only age, cigarette smoking, and family history of ARM have been consistently demonstrated to represent risk for this condition. In addition, genetic studies have recently implicated many genes in the pathogenesis of age-related maculopathy, including Complement Factor H, PLEKHA 1, and LOC387715/HTRA1, demonstrating that environmental and genetic factors are important for the development of ARM suggesting that gene-environment interaction plays an important role in the pathogenesis of this condition.