Estimated prevalence and risk factor for age-related maculopathy

Systemic Dyslipidemia in Age-related Macular Degeneration: An Updated Systematic Review and Meta-analysis

Topic

Though lipid and cholesterol dyshomeostasis is thought to contribute to the pathogenesis of age-related macular degeneration (AMD), there is no consensus regarding which elements of systemic lipid homeostasis are perturbed in AMD. In this systematic review and meta-analysis, an update to that performed by Wang et al in 2016, we characterized serum lipoprotein profiles in patients with AMD and its various stages.

Clinical Relevance

These findings may identify novel therapeutic approaches for AMD, a leading cause of blindness among older adults in the industrialized world.

Methods

We used MEDLINE, Embase, and Web of Science to identify articles from database inception to May 2022 that reported blood/serum levels of lipid subspecies (triglycerides [TGs], total cholesterol [TC], low-density lipoprotein [LDL], and high-density lipoprotein [HDL]) in patients with AMD compared with controls. We meta-analyzed the data by generating multilevel random-effects models using restricted maximum likelihood estimation.

Results

Our updated meta-analysis included 56 studies, almost 3 times as many studies as the 2016 meta-analysis with a total of 308 188 participants. There were no significant differences in serum TG, TC, LDL, or HDL between patients with AMD and non-AMD controls. Given significant heterogeneity, we performed subanalyses specifically in patients with early to intermediate nonexudative AMD, advanced nonexudative AMD, and advanced exudative AMD. Compared with non-AMD controls, patients with early to intermediate nonexudative AMD had significantly lower serum TG (standardized mean difference [SMD]: -0.03; 95% confidence interval [95% CI]: -0.06 to -0.01) and higher serum HDL (SMD: 0.07; 95% CI: 0.04-0.11). Patients with advanced exudative AMD had significantly higher serum LDL (SMD: 0.33; 95% CI: 0.04-0.62) compared with non-AMD controls. There were no other significant differences identified.

Conclusion

We found that there is significant heterogeneity in systemic lipoproteins in patients with AMD compared with non-AMD controls. The specific pattern of lipid dyshomeostasis appeared to be distinct based on AMD stage. These findings highlight both the underlying heterogeneity of AMD as well as the presence of distinct pathophysiological mechanisms involved at different stages or subtypes of AMD and may inform the development of novel therapeutic approaches.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Serum 25-Hydroxyvitamin D Is Differentially Associated with Early and Late Age-Related Macular Degeneration in the United States Population

BACKGROUND

Age-related macular degeneration (AMD) has been the leading cause of irreversible blindness in industrialized countries. Emerging data suggest that serum vitamin D levels may be associated with AMD but show mixed results. National-level population data on the relationship between vitamin D and AMD severities are still lacking.

METHODS

We used data from the National Health and Nutrition Examination Survey (NHANES) 2005 to 2008. Retinal photographs were taken and graded for AMD stage. The odds ratio (OR) of AMD and its subtype was calculated after adjusting for confounding factors. Restricted cubic spline (RCS) analyses were used to explore potential non-linear relations.

RESULTS

A total of 5041 participants with a mean age of 59.6 years were included. After adjusting for covariates, participants with higher level of serum 25-hydroxyvitamin D [25(OH)D] had significantly greater odds of early AMD (OR, 1.65; 95% CI, 1.08-2.51) and decreased risk of late AMD (OR, 0.29; 95% CI, 0.09-0.88). When stratified by age, a positive association between the level of serum 25(OH)D and early AMD was present in the <60 years group (OR, 2.79; 95% CI, 1.08-7.29), whereas a negative relation between the level of serum 25(OH)D and late AMD was detected in the ≥60 years group (OR, 0.24; 95% CI, 0.08-0.76).

CONCLUSIONS

A higher level of serum 25(OH)D was related to increased risk of early AMD in those <60 years and decreased risk of late AMD in those ≥60 years.

Systemic levels of C-reactive protein in patients with age-related macular degeneration: A systematic review with meta-analyses

Ageing of the retina is associated with the gradual accumulation of basal deposits and the formation of drusen. However, in some individuals this process is exacerbated and causes development of age-related macular degeneration. Late features of age-related macular degeneration include geographic atrophy of the neuroretina or choroidal neovascularization. Such changes lead to blurred vision, metamorphopsia, and scotoma, and is the leading cause of vision loss in developed countries. Chronic low-grade inflammation has been investigated because of its relationship to ageing and its role in the gap between chronological and biological ageing. Here, we systematically reviewed studies investigating systemic C-reactive protein in patients with age-related macular degeneration. We identified 53 studies with 60,598 participants (10,392 patients and 38,901 controls). Our meta-analyses revealed that early age-related macular degeneration was not associated to systemic C-reactive protein (Cohen's d = 0.03 [-0.04 to 0.10]; OR = 1.06 [0.93-1.20]; P = 0.39) whereas late age-related macular degeneration (Cohen's d = 0.38 [0.24 to 0.51]; OR = 1.99 [1.55-2.52]; P < 0.0001), and neovascular age-related macular degeneration (Cohen's d = 0.40 [0.24 to 0.56]; OR = 2.07 [1.55-2.76]; P < 0.0001) was associated with a small-to-moderate increase in systemic C-reactive protein. Our review provides an overview of this extensively studied field, provide summary estimates that provide insight into when and to what extent systemic C-reactive protein is associated with age-related macular degeneration, and help in distinguishing the potentially reversible disease processes from that of irreversible retinal ageing.

Implication of inflammatory cytokines in the aqueous humour for management of macular diseases

PURPOSE

To characterize profile of cytokines in aqueous humour of common macular diseases during intravitreal anti-VEGF therapy.

METHODS

Aqueous humour from eyes with central retinal vein occlusion (CRVO), branch retinal vein occlusion (BRVO), diabetic macular oedema (DME), neovascular age-related macular degeneration (nAMD) or pathologic myopia associated choroidal neovascularization (pmCNV) was sampled prior to 1st (n = 144) and 2nd (n = 48) intravitreal anti-VEGF therapy. Cytokines including vascular endothelium growth factor (VEGF), intercellular adhesion molecule 1 (ICAM-1) and interleukin 6 (IL-6) were quantitated and analysed along with retinal thickness data by optical coherence tomography (OCT) across two intravitreal injections and five macular disease types.

RESULTS

ICAM-1, IL-6 and VEGF are positively associated in the aqueous humour of naive eyes (r = 0.39-0.77, p = 0.018 to <0.0001). ICAM-1, VEGF and IL-6 were significantly higher in CRVO and DME while lowest in pmCNV (p < 0.0001). Reduction of central retinal thickness (CRT) as a favourable response to anti-VEGF therapy was in the order of CRVO, BRVO, DME and nAMD/pmCNV (p < 0.0001). The strongest predictor for favourable CRT reduction was baseline CRT (p < 0.0001) followed by baseline ICAM-1 (p = 0.04). After the 1st intravitreal anti-VEGF therapy, VEGF in aqueous humour lowered significantly but ICAM-1 and IL-6 levels remained unchanged. ICAM-1 was not predictive for CRT reduction following 2nd anti-VEGF therapy.

CONCLUSION

Rate of cytokine production is disease-dependent and higher in CRVO and DME. Anatomical response to intravitreal anti-VEGF therapy is disease-specific and best in RVO patients. A combination therapy using both anti-VEGF and anti-inflammatory therapeutics may be superior to single anti-VEGF therapy, at least for RVO and DME.

Low-vision intervention in individuals with age-related macular degeneration

Purpose:

The objective of this study was to estimate the level of visual impairment in patients diagnosed to have age-related macular degeneration (ARMD) who presented to low-vision care (LVC) clinic at a tertiary eye care center in India, to analyze the type of distant and near devices prescribed to them and to compare the visual benefit in different age groups among patients with ARMD.

Methods:

A retrospective review was done for 91 patients with low-vision secondary to ARMD who were referred to the LVC clinic from 2016 to 2017. Demographic profile: age, gender, occupation, ocular history, visual acuity status, and type of low-vision device (LVD) preferred were documented. The details of LVDs and subsequent improvements were noted.

Result:

Of the 91 patients, 64 (70.3%) were men and 27 (29.7%) were women. Of the cases which were referred, 36.26% had a severe visual impairment (VI), 32.96% had moderate VI, 28.57% had mild VI, and 5.49% had profound VI. The majority of the patients had myopia 57 (62.63%), followed by hyperopia in 25 (27.47%) subjects. The subjects were divided into three groups based on age 40–65 years, 66–75 years, and above 75 years for the analysis of VI. There was a statistically significant improvement (P < 0.01) in near vision with the help of LVDs in all three groups. SEE TV binocular telescope was the most commonly prescribed LVD for viewing distant objects. The most commonly preferred magnifier for near work was half-eye spectacle (56%) followed by stand magnifier (9.9%) and portable video magnifier (9.9%).

Conclusion:

The use of LVDs can help these patients with ARMD in cases where medical and surgical treatment have no or a limited role in restoring useful vision.

Rare variants and loci for age-related macular degeneration in the Ohio and Indiana Amish

Age-related macular degeneration (AMD) is a leading cause of blindness in the world. While dozens of independent genomic variants are associated with AMD, about one-third of AMD heritability is still unexplained. To identify novel variants and loci for AMD, we analyzed Illumina HumanExome chip data from 87 Amish individuals with early or late AMD, 79 unaffected Amish individuals, and 15 related Amish individuals with unknown AMD affection status. We retained 37,428 polymorphic autosomal variants across 175 samples for association and linkage analyses. After correcting for multiple testing (n = 37,428), we identified four variants significantly associated with AMD: rs200437673 (LCN9, p = 1.50 × 10-11), rs151214675 (RTEL1, p = 3.18 × 10-8), rs140250387 (DLGAP1, p = 4.49 × 10-7), and rs115333865 (CGRRF1, p = 1.05 × 10-6). These variants have not been previously associated with AMD and are not in linkage disequilibrium with the 52 known AMD-associated variants reported by the International AMD Genomics Consortium based on physical distance. Genome-wide significant linkage peaks were observed on chromosomes 8q21.11-q21.13 (maximum recessive HLOD = 4.03) and 18q21.2-21.32 (maximum dominant HLOD = 3.87; maximum recessive HLOD = 4.27). These loci do not overlap with loci previously linked to AMD. Through gene ontology enrichment analysis with ClueGO in Cytoscape, we determined that several genes in the 1-HLOD support interval of the chromosome 8 locus are involved in fatty acid binding and triglyceride catabolic processes, and the 1-HLOD support interval of the linkage region on chromosome 18 is enriched in genes that participate in serine-type endopeptidase inhibitor activity and the positive regulation of epithelial to mesenchymal transition. These results nominate novel variants and loci for AMD that require further investigation.

Association of chronic hepatitis B virus infection with age-related macular degeneration

PURPOSE

To study the association between chronic hepatitis B virus (HBV) and age-related macular degeneration (AMD).

METHODS

Data used in this retrospective, frequency-matched cohort study were acquired from the Longitudinal Health Insurance Database 2000, which includes medical claims and registration files for 1 000 000 enrolees in the Taiwan National Health Insurance programme. The HBV cohort contained 17 796 patients who received a diagnosis of chronic HBV infection between January 1, 2000 and December 31, 2012. The non-HBV cohort contained 71 184 participants who were frequency-matched by age, sex and year of index date for comparison. Participants were followed until the end of 2013, and those who developed AMD during the study period were identified. A Cox proportional hazards regression model was used to compare the risk of AMD between cohorts.

RESULTS

The incidence of any type of AMD in all participants was 3.88 per 1000 person-years (PY; 2.27 per 1000 PY in the HBV cohort; 1.61 per 1000 PY in the non-HBV cohort). Compared with the non-HBV cohort, the adjusted hazard ratio (HR) for any type of AMD in the HBV cohort was 1.41 [95% confidence interval (CI) 1.23-1.63; p < 0.001]. This significant positive association was stronger among patients who exhibited disease progression from nonexudative to exudative AMD (adjusted HR = 1.74, 95% CI: 1.01-2.99).

CONCLUSION

Our results suggest that patients with chronic HBV infection in Taiwan have a significantly elevated risk of developing any type of AMD and that HBV infection may accelerate the progression of AMD.

Systemic and ocular fluid compounds as potential biomarkers in age-related macular degeneration

Biomarkers can help unravel mechanisms of disease and identify new targets for therapy. They can also be useful in clinical practice for monitoring disease progression, evaluation of treatment efficacy, and risk assessment in multifactorial diseases, such as age-related macular degeneration (AMD). AMD is a highly prevalent progressive retinal disorder for which multiple genetic and environmental risk factors have been described, but the exact etiology is not yet fully understood. Many compounds have been evaluated for their association with AMD. We performed an extensive literature review of all compounds measured in serum, plasma, vitreous, aqueous humor, and urine of AMD patients. Over 3600 articles were screened, resulting in more than 100 different compounds analyzed in AMD studies, involved in neovascularization, immunity, lipid metabolism, extracellular matrix, oxidative stress, diet, hormones, and comorbidities (such as kidney disease). For each compound, we provide a short description of its function and discuss the results of the studies in relation to its usefulness as AMD biomarker. In addition, biomarkers identified by hypothesis-free techniques, including metabolomics, proteomics, and epigenomics, are covered. In summary, compounds belonging to the oxidative stress pathway, the complement system, and lipid metabolism are the most promising biomarker candidates for AMD. We hope that this comprehensive survey of the literature on systemic and ocular fluid compounds as potential biomarkers in AMD will provide a stepping stone for future research and possible implementation in clinical practice.

The association between periodontal disease and age-related macular degeneration in the Korea National health and nutrition examination survey: A cross-sectional observational study

Periodontal disease (PD) is associated with various systemic diseases. We investigated the association between PD and age-related macular degeneration (AMD).For this population-based, cross-sectional study, we enrolled 13,072 adults at least 40 years of age with gradable retinal fundus photographs and community periodontal index (CPI) data from the Korean National Health and Nutrition Examination Survey (KNHANES) (2008-2010 and 2012). Participants were divided into a middle age group (age ≤62 years) and old age group (age >62 years). PD was divided into 2 categories of mild and severe. Logistic regression analysis was used to evaluate the association between PD and AMD (early and late).The prevalence of PD and AMD in the study population was 37.4% ± 0.8% and 5.6% ± 0.2%, respectively. Overall, there was no significant difference in the proportion of participants with PD between those with and without AMD. Only participants with AMD in the middle age group had more any PD than those without AMD (P = 0.031). Multivariate logistic regression model after adjusting for all confounding factors showed that PD was not significantly associated with AMD (odds ratio [OR] 1.03, 95% confidence interval [CI] 0.86-1.22). However, according to degree of PD, participants with severe PD in the middle age group were 1.61 times more likely to have AMD (OR 1.61, 95% CI 1.02-2.54).Our data, collected from an Asian population, showed that only severe PD is independently associated with AMD in individuals aged 62 years or younger.

Epidemiology of age-related macular degeneration (AMD): associations with cardiovascular disease phenotypes and lipid factors

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in adults over 50 years old. Genetic, epidemiological, and molecular studies are beginning to unravel the intricate mechanisms underlying this complex disease, which implicate the lipid-cholesterol pathway in the pathophysiology of disease development and progression. Many of the genetic and environmental risk factors associated with AMD are also associated with other complex degenerative diseases of advanced age, including cardiovascular disease (CVD). In this review, we present epidemiological findings associating AMD with a variety of lipid pathway genes, cardiovascular phenotypes, and relevant environmental exposures. Despite a number of studies showing significant associations between AMD and these lipid/cardiovascular factors, results have been mixed and as such the relationships among these factors and AMD remain controversial. It is imperative that researchers not only tease out the various contributions of such factors to AMD development but also the connections between AMD and CVD to develop optimal precision medical care for aging adults.

The Association between the Lipids Levels in Blood and Risk of Age-Related Macular Degeneration

Lipid metabolism may be involved in the pathogenic mechanism of age-related macular degeneration (AMD). However, conflicting results have been reported in the associations of AMD with blood lipids. We performed a meta-analysis including a total of 19 studies to evaluate associations between blood lipids and this disease. The result reported that the high level of high-density lipoprotein cholesterol (HDL-C) obtained with an increment of 1 mmol/L could result in a significantly increase in the AMD risk of approximately 18% (relative risk (RR), 1.18; 95% confidence interval (CI), 1.01 to 1.35; I² = 53.8%; p = 0.007). High levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG) were significantly associated with a decreased risk of AMD (RRs ranging from 0.92 to 0.95; all p < 0.05). The stratified analysis based on AMD subtypes showed that these blood lipids were only significantly associated with the risk of early AMD (all p < 0.05). The association between the blood lipids and AMD risk did not differ substantially based on the other characteristics of the participants. A high HDL-C level was associated with an increased AMD risk, whereas participants with high TC, LDL-C, and TG concentrations may show a decreased risk for this disease. Further well-designed large studies are warranted to confirm the conclusions.

Geo-Epidemiology of Age-Related Macular Degeneration: New Clues Into the Pathogenesis

PURPOSE

To evaluate the demographic, geographic, and race-related variables that account for geographic variability in prevalence rates of age-related macular degeneration (AMD).

DESIGN

Systematic review, meta-regression, and decision-tree analysis.

METHODS

A systematic literature review of PubMed, Medline, Web of Science, and Embase databases identified population-based studies on the prevalence of AMD published before May 2014. Only population-based studies that took place in a spatially explicit geographic area that could be geolocalized, and used retinal photographs and standardized grading classifications, were included. Latitude and longitude data (geolocalization) and the mean annual insolation for the area where survey took place were obtained. Age-standardized prevalence rates across studies were estimated using the direct standardization method. Correlations between the prevalence of AMD and longitude and latitude were obtained by regression analysis. A hierarchical Bayesian meta-regression approach was used to assess the association between the prevalence of AMD and other relevant factors. We further investigated the interplay between location and these factors on the prevalence of AMD using regression based on conditional-inference decision trees.

RESULTS

We observed significant inverse correlations between latitude or longitude, and crude or age-standardized prevalence rates, of early and late AMD (P < .001). Metaregression analysis showed that insolation, latitude, longitude, age, and race have a significant effect on the prevalence rates of early and late AMD (P < .001). Decision-tree analysis identified that the most important predictive variable was race for early AMD (P = .002) and insolation for late AMD (P = .001).

CONCLUSIONS

Geographic position and insolation are key factors in the prevalence of AMD.

Age-related macular degeneration: prevalence and risk factors from Korean National Health and Nutrition Examination Survey, 2008 through 2011

OBJECTIVE

To investigate the prevalence and risk factors of age-related macular degeneration (AMD) in the Korean population.

DESIGN

A cross-sectional study using a complex, stratified, multistage, probability-cluster survey, which can produce nationally representative estimates.

PARTICIPANTS

Using the database of Korean National Health and Nutrition Examination Survey from 2008 through 2011, 14 352 participants 40 years of age or older with gradable fundus photographs were included.

METHODS

Age-related macular degeneration was determined by fundus photograph. Prevalences of AMDs were estimated. Risk factor analyses were conducted using logistic regression analyses (LRAs).

MAIN OUTCOME MEASURES

Prevalence and risk factors of AMD.

RESULTS

The prevalence of AMD was 6.62% (95% confidence interval [CI], 6.15%-7.09%) in the Korean population: 6.02% (95% CI, 5.56%-6.48%) were early AMD and 0.60% (95% CI, 0.45%-0.75%) were late AMD. The prevalence of early AMD in women (6.73%; 95% CI, 6.11%-7.35%) was higher than that in men (5.25%; 95% CI, 4.61%-5.89%; P<0.001), and the prevalence of late AMD in women (0.37%; 95% CI, 0.22%-0.52%) was lower than that in men (0.85%; 95% CI, 0.59%-1.12%; P<0.001). However, in multiple LRAs both early and late AMD had no association with gender, house income, residence, sun exposure, or systemic comorbidities, including hypertension, diabetes mellitus, and cardiovascular diseases. Early AMD had positive associations with older age groups (P<0.001), lower education (P = 0.027), occupation (P<0.001), anemia (P = 0.027), hepatitis B surface antigen carrier status (P<0.001), not being overweight (body mass index [BMI], P = 0.032; waist circumference, P = 0.041, in separate analyses), and higher serum high-density lipoprotein (HDL) level (P = 0.046), but not with smoking status. Late AMD had positive associations with age groups (P<0.001), current smokers (P = 0.022), and lower BMI (P = 0.037).

CONCLUSIONS

The results suggest that there are 1.21 million individuals with early AMD and 121 000 individuals with late AMD in Korea. Nonoverweight status and higher HDL levels, generally assumed as positive health indicators, as well as anemia and hepatitis B infection had harmful associations with AMD in our study, implying a possible different pathophysiologic process of AMD in Asians compared with that of white persons.