@article {1003, title = {Apolipoprotein E gene and retinal microvascular signs in older people: the Cardiovascular Health Study.}, journal = {Mol Vis}, volume = {13}, year = {2007}, month = {2007 Nov 12}, pages = {2105-11}, abstract = {

PURPOSE: To examine the association between apolipoprotein E (APOE) gene polymorphism and retinal microvascular signs in an older population.

METHODS: Retinal photographs were taken of 2,152 participants (1,831 whites, and 321 African-Americans), aged 69-96 years, who were participating in a population-based study of four United States communities. We used standardized protocols to assess photographs for the presence of retinal microvascular signs (retinopathy, arterio-venous nicking, and focal arteriolar narrowing) and a computer-assisted method to measure retinal vessel diameters. We analyzed DNA extracted from blood samples of participants for common allelic variants of the APOE gene.

RESULTS: After adjusting for age, gender, systolic blood pressure, smoking, total serum cholesterol, and other risk factors, we found white participants carrying the epsilon2 and epsilon4 alleles were more likely to have arterio-venous nicking than the epsilon3/epsilon3 homozygotes, with odds ratio (OR) of 1.70 and confidence interval (CI) 95\% (1.03-2.83) for the epsilon2 carriers and OR 1.74 (95\% CI 1.06-2.84) for the epsilon4 carriers. Among white participants without hypertension, the associations remained significant for the epsilon4 carriers (OR 2.32, 95\% CI 1.18-4.57). Whites, normotensive carriers of the epsilon2 allele had significantly narrower retinal arteriolar diameters (adjusted mean arteriolar diameter of 163.5 mum, 95\% CI 160.1-167.0, p=0.03) compared to the epsilon3/epsilon3 homozygotes (167.8 mum, 95\% CI 166.0-169.6). APOE gene polymorphism was not associated with retinopathy, focal narrowing, or retinal venular diameters in white participants. There were insufficient numbers of African-Americans for separate multivariate analysis.

CONCLUSIONS: This study provides little evidence that the APOE gene polymorphism plays a significant role in the pathogenesis of retinal microvascular changes in the general population. In the older white population, APOE epsilon2 and epsilon4 allele carriers were more likely to have arterio-venous nicking. Other retinal signs, however, were not related to APOE gene polymorphism.

}, keywords = {Aged, Aged, 80 and over, Apolipoprotein E2, Apolipoprotein E4, Apolipoproteins E, European Continental Ancestry Group, Female, Gene Frequency, Genotype, Heterozygote, Homozygote, Humans, Male, Microcirculation, Polymorphism, Genetic, Retinal Diseases, Retinal Vessels}, issn = {1090-0535}, author = {Sun, Cong and Tikellis, Gabriella and Liew, Gerald and Klein, Ronald and Larsen, Emily K Marino and Wong, Tien Y} } @article {1129, title = {Meta-analysis: retinal vessel caliber and risk for coronary heart disease.}, journal = {Ann Intern Med}, volume = {151}, year = {2009}, month = {2009 Sep 15}, pages = {404-13}, abstract = {

BACKGROUND: Retinal vessel caliber may be a novel marker of coronary heart disease (CHD) risk. However, the sex-specific effect, magnitude of association, and effect independent of traditional CHD disease risk factors remain unclear.

PURPOSE: To determine the association between retinal vessel caliber and risk for CHD.

DATA SOURCES: Relevant studies in any language identified through MEDLINE (1950 to June 2009) and EMBASE (1950 to June 2009) databases.

STUDY SELECTION: Studies were included if they examined a general population, measured retinal vessel caliber from retinal photographs, and documented CHD risk factors and incident CHD events.

DATA EXTRACTION: 6 population-based prospective cohort studies provided data for individual participant meta-analysis.

DATA SYNTHESIS: Proportional hazards models, adjusted for traditional CHD risk factors, were constructed for retinal vessel caliber and incident CHD in women and men. Among 22,159 participants who were free of CHD and followed for 5 to 14 years, 2219 (10.0\%) incident CHD events occurred. Retinal vessel caliber changes (wider venules and narrower arterioles) were each associated with an increased risk for CHD in women (pooled multivariable-adjusted hazard ratios, 1.16 [95\% CI, 1.06 to 1.26] per 20-microm increase in venular caliber and 1.17 [CI, 1.07 to 1.28] per 20-microm decrease in arteriolar caliber) but not in men (1.02 [CI, 0.94 to 1.10] per 20-microm increase in venular caliber and 1.02 [CI, 0.95 to 1.10] per 20-microm decrease in arteriolar caliber). Women without hypertension or diabetes had higher hazard ratios.

LIMITATION: Error in the measurement of retinal vessel caliber and Framingham variables was not taken into account.

CONCLUSION: Retinal vessel caliber changes were independently associated with an increased risk for CHD events in women.

}, keywords = {Adult, Aged, Arterioles, Biomarkers, Coronary Disease, Female, Humans, Male, Middle Aged, Proportional Hazards Models, Retinal Vessels, Risk Factors, Sex Factors, Venules}, issn = {1539-3704}, author = {McGeechan, Kevin and Liew, Gerald and Macaskill, Petra and Irwig, Les and Klein, Ronald and Klein, Barbara E K and Wang, Jie Jin and Mitchell, Paul and Vingerling, Johannes R and Dejong, Paulus T V M and Witteman, Jacqueline C M and Breteler, Monique M B and Shaw, Jonathan and Zimmet, Paul and Wong, Tien Y} } @article {1142, title = {Prediction of incident stroke events based on retinal vessel caliber: a systematic review and individual-participant meta-analysis.}, journal = {Am J Epidemiol}, volume = {170}, year = {2009}, month = {2009 Dec 01}, pages = {1323-32}, abstract = {

The caliber of the retinal vessels has been shown to be associated with stroke events. However, the consistency and magnitude of association, and the changes in predicted risk independent of traditional risk factors, are unclear. To determine the association between retinal vessel caliber and the risk of stroke events, the investigators combined individual data from 20,798 people, who were free of stroke at baseline, in 6 cohort studies identified from a search of the Medline (National Library of Medicine, Bethesda, Maryland) and EMBASE (Elsevier B.V., Amsterdam, the Netherlands) databases. During follow-up of 5-12 years, 945 (4.5\%) incident stroke events were recorded. Wider retinal venular caliber predicted stroke (pooled hazard ratio = 1.15, 95\% confidence interval: 1.05, 1.25 per 20-micron increase in caliber), but the caliber of retinal arterioles was not associated with stroke (pooled hazard ratio = 1.00, 95\% confidence interval: 0.92, 1.08). There was weak evidence of heterogeneity in the hazard ratio for retinal venular caliber, which may be attributable to differences in follow-up strategies across studies. Inclusion of retinal venular caliber in prediction models containing traditional stroke risk factors reassigned 10.1\% of people at intermediate risk into different, mostly lower, risk categories.

}, keywords = {Aged, Fluorescein Angiography, Humans, Middle Aged, Predictive Value of Tests, Proportional Hazards Models, Retinal Artery, Retinal Vein, Retinal Vessels, Risk Factors, Stroke}, issn = {1476-6256}, doi = {10.1093/aje/kwp306}, author = {McGeechan, Kevin and Liew, Gerald and Macaskill, Petra and Irwig, Les and Klein, Ronald and Klein, Barbara E K and Wang, Jie Jin and Mitchell, Paul and Vingerling, Johannes R and de Jong, Paulus T V M and Witteman, Jacqueline C M and Breteler, Monique M B and Shaw, Jonathan and Zimmet, Paul and Wong, Tien Y} } @article {1243, title = {Four novel Loci (19q13, 6q24, 12q24, and 5q14) influence the microcirculation in vivo.}, journal = {PLoS Genet}, volume = {6}, year = {2010}, month = {2010 Oct 28}, pages = {e1001184}, abstract = {

There is increasing evidence that the microcirculation plays an important role in the pathogenesis of cardiovascular diseases. Changes in retinal vascular caliber reflect early microvascular disease and predict incident cardiovascular events. We performed a genome-wide association study to identify genetic variants associated with retinal vascular caliber. We analyzed data from four population-based discovery cohorts with 15,358 unrelated Caucasian individuals, who are members of the Cohort for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium, and replicated findings in four independent Caucasian cohorts (n  =  6,652). All participants had retinal photography and retinal arteriolar and venular caliber measured from computer software. In the discovery cohorts, 179 single nucleotide polymorphisms (SNP) spread across five loci were significantly associated (p<5.0{\texttimes}10(-8)) with retinal venular caliber, but none showed association with arteriolar caliber. Collectively, these five loci explain 1.0\%-3.2\% of the variation in retinal venular caliber. Four out of these five loci were confirmed in independent replication samples. In the combined analyses, the top SNPs at each locus were: rs2287921 (19q13; p  =  1.61{\texttimes}10(-25), within the RASIP1 locus), rs225717 (6q24; p = 1.25{\texttimes}10(-16), adjacent to the VTA1 and NMBR loci), rs10774625 (12q24; p  =  2.15{\texttimes}10(-13), in the region of ATXN2,SH2B3 and PTPN11 loci), and rs17421627 (5q14; p = 7.32{\texttimes}10(-16), adjacent to the MEF2C locus). In two independent samples, locus 12q24 was also associated with coronary heart disease and hypertension. Our population-based genome-wide association study demonstrates four novel loci associated with retinal venular caliber, an endophenotype of the microcirculation associated with clinical cardiovascular disease. These data provide further insights into the contribution and biological mechanisms of microcirculatory changes that underlie cardiovascular disease.

}, keywords = {Adolescent, Adult, Aged, Aged, 80 and over, Cardiovascular Diseases, Child, Child, Preschool, Chromosomes, Human, Pair 12, Chromosomes, Human, Pair 19, Chromosomes, Human, Pair 5, Chromosomes, Human, Pair 6, Cohort Studies, European Continental Ancestry Group, Female, Genetic Loci, Genome-Wide Association Study, Humans, Male, Meta-Analysis as Topic, Microcirculation, Middle Aged, Polymorphism, Single Nucleotide, Retinal Vessels, Young Adult}, issn = {1553-7404}, doi = {10.1371/journal.pgen.1001184}, author = {Ikram, M Kamran and Sim, Xueling and Xueling, Sim and Jensen, Richard A and Cotch, Mary Frances and Hewitt, Alex W and Ikram, M Arfan and Wang, Jie Jin and Klein, Ronald and Klein, Barbara E K and Breteler, Monique M B and Cheung, Ning and Liew, Gerald and Mitchell, Paul and Uitterlinden, Andr{\'e} G and Rivadeneira, Fernando and Hofman, Albert and de Jong, Paulus T V M and van Duijn, Cornelia M and Kao, Linda and Cheng, Ching-Yu and Smith, Albert Vernon and Glazer, Nicole L and Lumley, Thomas and McKnight, Barbara and Psaty, Bruce M and Jonasson, Fridbert and Eiriksdottir, Gudny and Aspelund, Thor and Harris, Tamara B and Launer, Lenore J and Taylor, Kent D and Li, Xiaohui and Iyengar, Sudha K and Xi, Quansheng and Sivakumaran, Theru A and Mackey, David A and Macgregor, Stuart and Martin, Nicholas G and Young, Terri L and Bis, Josh C and Wiggins, Kerri L and Heckbert, Susan R and Hammond, Christopher J and Andrew, Toby and Fahy, Samantha and Attia, John and Holliday, Elizabeth G and Scott, Rodney J and Islam, F M Amirul and Rotter, Jerome I and McAuley, Annie K and Boerwinkle, Eric and Tai, E Shyong and Gudnason, Vilmundur and Siscovick, David S and Vingerling, Johannes R and Wong, Tien Y} } @article {6072, title = {Genome-wide association study of retinopathy in individuals without diabetes.}, journal = {PLoS One}, volume = {8}, year = {2013}, month = {2013}, pages = {e54232}, abstract = {

BACKGROUND: Mild retinopathy (microaneurysms or dot-blot hemorrhages) is observed in persons without diabetes or hypertension and may reflect microvascular disease in other organs. We conducted a genome-wide association study (GWAS) of mild retinopathy in persons without diabetes.

METHODS: A working group agreed on phenotype harmonization, covariate selection and analytic plans for within-cohort GWAS. An inverse-variance weighted fixed effects meta-analysis was performed with GWAS results from six cohorts of 19,411 Caucasians. The primary analysis included individuals without diabetes and secondary analyses were stratified by hypertension status. We also singled out the results from single nucleotide polymorphisms (SNPs) previously shown to be associated with diabetes and hypertension, the two most common causes of retinopathy.

RESULTS: No SNPs reached genome-wide significance in the primary analysis or the secondary analysis of participants with hypertension. SNP, rs12155400, in the histone deacetylase 9 gene (HDAC9) on chromosome 7, was associated with retinopathy in analysis of participants without hypertension, -1.3{\textpm}0.23 (beta {\textpm} standard error), p = 6.6{\texttimes}10(-9). Evidence suggests this was a false positive finding. The minor allele frequency was low (\~{}2\%), the quality of the imputation was moderate (r(2) \~{}0.7), and no other common variants in the HDAC9 gene were associated with the outcome. SNPs found to be associated with diabetes and hypertension in other GWAS were not associated with retinopathy in persons without diabetes or in subgroups with or without hypertension.

CONCLUSIONS: This GWAS of retinopathy in individuals without diabetes showed little evidence of genetic associations. Further studies are needed to identify genes associated with these signs in order to help unravel novel pathways and determinants of microvascular diseases.

}, keywords = {Aged, Aged, 80 and over, Female, Genome-Wide Association Study, Genotype, Histone Deacetylases, Humans, Hypertension, Male, Polymorphism, Single Nucleotide, Repressor Proteins, Retinal Diseases}, issn = {1932-6203}, doi = {10.1371/journal.pone.0054232}, author = {Jensen, Richard A and Sim, Xueling and Li, Xiaohui and Cotch, Mary Frances and Ikram, M Kamran and Holliday, Elizabeth G and Eiriksdottir, Gudny and Harris, Tamara B and Jonasson, Fridbert and Klein, Barbara E K and Launer, Lenore J and Smith, Albert Vernon and Boerwinkle, Eric and Cheung, Ning and Hewitt, Alex W and Liew, Gerald and Mitchell, Paul and Wang, Jie Jin and Attia, John and Scott, Rodney and Glazer, Nicole L and Lumley, Thomas and McKnight, Barbara and Psaty, Bruce M and Taylor, Kent and Hofman, Albert and de Jong, Paulus T V M and Rivadeneira, Fernando and Uitterlinden, Andr{\'e} G and Tay, Wan-Ting and Teo, Yik Ying and Seielstad, Mark and Liu, Jianjun and Cheng, Ching-Yu and Saw, Seang-Mei and Aung, Tin and Ganesh, Santhi K and O{\textquoteright}Donnell, Christopher J and Nalls, Mike A and Wiggins, Kerri L and Kuo, Jane Z and van Duijn, Cornelia M and Gudnason, Vilmundur and Klein, Ronald and Siscovick, David S and Rotter, Jerome I and Tai, E Shong and Vingerling, Johannes and Wong, Tien Y} } @article {5875, title = {Insights into the genetic architecture of early stage age-related macular degeneration: a genome-wide association study meta-analysis.}, journal = {PLoS One}, volume = {8}, year = {2013}, month = {2013}, pages = {e53830}, abstract = {

Genetic factors explain a majority of risk variance for age-related macular degeneration (AMD). While genome-wide association studies (GWAS) for late AMD implicate genes in complement, inflammatory and lipid pathways, the genetic architecture of early AMD has been relatively under studied. We conducted a GWAS meta-analysis of early AMD, including 4,089 individuals with prevalent signs of early AMD (soft drusen and/or retinal pigment epithelial changes) and 20,453 individuals without these signs. For various published late AMD risk loci, we also compared effect sizes between early and late AMD using an additional 484 individuals with prevalent late AMD. GWAS meta-analysis confirmed previously reported association of variants at the complement factor H (CFH) (peak P = 1.5{\texttimes}10(-31)) and age-related maculopathy susceptibility 2 (ARMS2) (P = 4.3{\texttimes}10(-24)) loci, and suggested Apolipoprotein E (ApoE) polymorphisms (rs2075650; P = 1.1{\texttimes}10(-6)) associated with early AMD. Other possible loci that did not reach GWAS significance included variants in the zinc finger protein gene GLI3 (rs2049622; P = 8.9{\texttimes}10(-6)) and upstream of GLI2 (rs6721654; P = 6.5{\texttimes}10(-6)), encoding retinal Sonic hedgehog signalling regulators, and in the tyrosinase (TYR) gene (rs621313; P = 3.5{\texttimes}10(-6)), involved in melanin biosynthesis. For a range of published, late AMD risk loci, estimated effect sizes were significantly lower for early than late AMD. This study confirms the involvement of multiple established AMD risk variants in early AMD, but suggests weaker genetic effects on the risk of early AMD relative to late AMD. Several biological processes were suggested to be potentially specific for early AMD, including pathways regulating RPE cell melanin content and signalling pathways potentially involved in retinal regeneration, generating hypotheses for further investigation.

}, keywords = {Apolipoproteins E, Complement Factor H, Genetic Predisposition to Disease, Genome-Wide Association Study, Genotype, Humans, Kruppel-Like Transcription Factors, Macular Degeneration, Nerve Tissue Proteins, Polymorphism, Single Nucleotide, Proteins, Risk Factors, Zinc Finger Protein Gli3}, issn = {1932-6203}, doi = {10.1371/journal.pone.0053830}, author = {Holliday, Elizabeth G and Smith, Albert V and Cornes, Belinda K and Buitendijk, Gabri{\"e}lle H S and Jensen, Richard A and Sim, Xueling and Aspelund, Thor and Aung, Tin and Baird, Paul N and Boerwinkle, Eric and Cheng, Ching Yu and van Duijn, Cornelia M and Eiriksdottir, Gudny and Gudnason, Vilmundur and Harris, Tamara and Hewitt, Alex W and Inouye, Michael and Jonasson, Fridbert and Klein, Barbara E K and Launer, Lenore and Li, Xiaohui and Liew, Gerald and Lumley, Thomas and McElduff, Patrick and McKnight, Barbara and Mitchell, Paul and Psaty, Bruce M and Rochtchina, Elena and Rotter, Jerome I and Scott, Rodney J and Tay, Wanting and Taylor, Kent and Teo, Yik Ying and Uitterlinden, Andr{\'e} G and Viswanathan, Ananth and Xie, Sophia and Vingerling, Johannes R and Klaver, Caroline C W and Tai, E Shyong and Siscovick, David and Klein, Ronald and Cotch, Mary Frances and Wong, Tien Y and Attia, John and Wang, Jie Jin} } @article {7590, title = {Genetically Determined Plasma Lipid Levels and Risk of Diabetic Retinopathy: A Mendelian Randomization Study.}, journal = {Diabetes}, volume = {66}, year = {2017}, month = {2017 12}, pages = {3130-3141}, abstract = {

Results from observational studies examining dyslipidemia as a risk factor for diabetic retinopathy (DR) have been inconsistent. We evaluated the causal relationship between plasma lipids and DR using a Mendelian randomization approach. We pooled genome-wide association studies summary statistics from 18 studies for two DR phenotypes: any DR (N = 2,969 case and 4,096 control subjects) and severe DR (N = 1,277 case and 3,980 control subjects). Previously identified lipid-associated single nucleotide polymorphisms served as instrumental variables. Meta-analysis to combine the Mendelian randomization estimates from different cohorts was conducted. There was no statistically significant change in odds ratios of having any DR or severe DR for any of the lipid fractions in the primary analysis that used single nucleotide polymorphisms that did not have a pleiotropic effect on another lipid fraction. Similarly, there was no significant association in the Caucasian and Chinese subgroup analyses. This study did not show evidence of a causal role of the four lipid fractions on DR. However, the study had limited power to detect odds ratios less than 1.23 per SD in genetically induced increase in plasma lipid levels, thus we cannot exclude that causal relationships with more modest effect sizes exist.

}, keywords = {Aged, Diabetic Retinopathy, Female, Genome-Wide Association Study, Humans, Lipids, Male, Mendelian Randomization Analysis, Middle Aged, Polymorphism, Single Nucleotide, Risk}, issn = {1939-327X}, doi = {10.2337/db17-0398}, author = {Sobrin, Lucia and Chong, Yong He and Fan, Qiao and Gan, Alfred and Stanwyck, Lynn K and Kaidonis, Georgia and Craig, Jamie E and Kim, Jihye and Liao, Wen-Ling and Huang, Yu-Chuen and Lee, Wen-Jane and Hung, Yi-Jen and Guo, Xiuqing and Hai, Yang and Ipp, Eli and Pollack, Samuela and Hancock, Heather and Price, Alkes and Penman, Alan and Mitchell, Paul and Liew, Gerald and Smith, Albert V and Gudnason, Vilmundur and Tan, Gavin and Klein, Barbara E K and Kuo, Jane and Li, Xiaohui and Christiansen, Mark W and Psaty, Bruce M and Sandow, Kevin and Jensen, Richard A and Klein, Ronald and Cotch, Mary Frances and Wang, Jie Jin and Jia, Yucheng and Chen, Ching J and Chen, Yii-Der Ida and Rotter, Jerome I and Tsai, Fuu-Jen and Hanis, Craig L and Burdon, Kathryn P and Wong, Tien Yin and Cheng, Ching-Yu} }