Estrogen receptors alpha and beta and the risk of open-angle glaucoma: the Rotterdam Study

OBJECTIVE

To investigate whether polymorphisms in the estrogen receptor alpha (ESR1) and beta (ESR2) genes were a risk factor for open-angle glaucoma (OAG).

METHODS

Participants 55 years and older from the population-based Rotterdam Study underwent, at baseline and at follow-up, the same ophthalmic examination, including visual field screening and stereo optic disc photography. A diagnosis of OAG was based on an algorithm using optic disc measures and visual field loss. Haplotypes of the ESR1 and ESR2 genes were determined.

RESULTS

We diagnosed incident OAG in 87 of 3842 participants (2.3%) at risk after a mean follow-up of 6.5 years. We could not detect any association with ESR1 haplotypes. Haplotype 1 of ESR2 showed a 3.6-fold (95% confidence interval, 1.4-9.2) higher risk of incident OAG in men. In women, no association was found between ESR2 and incident OAG.

CONCLUSION

Polymorphisms in the ESR1 gene are unrelated to OAG, but ESR2 polymorphisms seem to lead to increased risk of OAG in men.

Risk of bilateral visual impairment in individuals with amblyopia: the Rotterdam study

BACKGROUND

The excess risk of bilateral visual impairment (BVI; bilateral visual acuity <0.5) among individuals with amblyopia is an argument for screening for amblyopia, but data are scarce.

METHODS

The risk was estimated by determining the incidence of BVI in the Rotterdam Study, a population-based cohort of subjects aged 55 years or over (n = 5220), including 192 individuals with amblyopia (3.7%). Using a multistate lifetable, the lifetime risk and excess period spent with BVI were determined.

RESULTS

The relative risk of BVI for amblyopes was 2.6 (95% confidence interval 1.4-4.5). For individuals with amblyopia, the lifetime risk of BVI was 18%, whereas they lived on average 7.2 years with BVI. For non-amblyopic individuals, these figures were 10% and 6.7 years, respectively.

CONCLUSION

Amblyopia nearly doubles the lifetime risk of BVI and affected individuals spent an extra six months with BVI. This study provides data for future cost-effectiveness analyses.

C-reactive protein level and risk of aging macula disorder: The Rotterdam Study

OBJECTIVE

To examine whether C-reactive protein (CRP) level is a risk factor for aging macula disorder (AMD) in a general population.

METHODS

We examined serum high-sensitivity CRP (HsCRP) levels in 4914 participants of the population-based Rotterdam Study at risk for AMD. After a mean follow-up of 7.7 years, 561 cases of early and 97 cases of late incident AMD (iAMD) were identified. We used Cox proportional hazards regression models to estimate hazard ratios and corresponding 95% confidence intervals (CIs).

RESULTS

After adjustment for age and sex, hazard ratios were 1.11 (95% CI, 1.02-1.21) per standard deviation increase in HsCRP level for early iAMD and 1.28 (95% CI, 1.02-1.60) for late iAMD. Hazard ratios for early iAMD increased per quartile increase in HsCRP level as follows: second quartile, 1.19 (95% CI, 0.94-1.52); third quartile, 1.29 (95% CI, 1.01-1.64); and fourth quartile, 1.33 (95% CI, 1.05-1.70). The risk of late iAMD was higher in all upper quartiles of HsCRP.

CONCLUSION

Elevated baseline levels of HsCRP were associated with the development of early and late AMD in this large population-based cohort.

Mutation analysis in a family with oculocutaneous albinism manifesting in the same generation of three branches

PURPOSE

To elucidate the molecular basis of oculocutaneous albinism with variable expressivity in a family from The Netherlands in which no consanguinity was reported.

METHODS

Three affected family members were screened for mutations in tyrosinase (TYR) and the pink-eye-dilution gene (P) by using SSCP. The melanocortin receptor gene (MC1R) and amplimers of P showing an aberrant banding pattern in SSCP were analyzed by direct sequencing. All participants underwent ophthalmologic examination including funduscopy, and visually evoked potentials were recorded in two cases.

RESULTS

The pedigree had three branches A, B, and C. We identified three mutations in P (V443I, N476S, C793F) that cause a compound heterozygous situation in cases from branch A (N476S/C793F) and B (V443I/C793F), who showed oculocutaneous albinism. Hair and skin color followed the light Nordic complexion that was also present in other affected and unaffected members of this family. Descendants of branches A and B showed light complexion with iris translucency and peripheral fundus hypopigmentation independent from the genotype identified. A single descendant had red hair, carrying a well known compound MC1R mutation combination for red hair color and a single heterozygous P mutation.

CONCLUSIONS

P mutations underlie oculocutaneous albinism in this family. Two known mutations in MC1R caused red hair color in one family member. No modifier effect of MC1R on P mutations could be deduced from the results of this study.

Comparison of human retinal pigment epithelium gene expression in macula and periphery highlights potential topographic differences in Bruch's membrane

PURPOSE

To describe gene expression differences between healthy, young human retinal pigment epithelium (RPE) cells from the macular area and RPE cells from two locations in the retinal periphery.

METHODS

RPE cells from six human donor eyes, ages 17-36, without histopathological abnormalities, were dissected by laser and isolated from cryosections. Total RNA was isolated, amplified, and hybridized to a custom made oligonucleotide array containing 22,000 genes. Bioinformatic analysis was carried out using the computer programs Rosetta Resolver and the webtools EASE/David and GoStat. Confirmatory real time PCR (RT-PCR) and immunohistochemistry were performed according to standard protocols.

RESULTS

Microarray and statistical analysis yielded 438 genes that were differentially expressed between macular RPE, and at least one out of two peripheral RPE locations. Out of these genes, 33 that showed fold changes of four, or higher, were selected for RT-PCR confirmation. For 17 genes (51%), a significant differential expression was found, while 11 additional genes (33%) showed a similar trend. Immuno-staining of one target (WFDC1) confirmed its differential expression on the protein level. Functional annotation and overrepresentation analysis independently defined extracellular matrix (ECM) genes as a statistically overrepresented class of genes in our RPE dataset. In total, 33 ECM genes were differentially expressed between macular and peripheral RPE regions. A subset of proteins corresponding to these genes is known to be present in Bruch's membrane.

CONCLUSIONS

Our data showed that consistent topographical gene expression differences in the human RPE constitute around 1-5% of the RPE transcriptome. These changes may underlie topographical differences in RPE physiology, and pathology and may reflect local differences in the molecular composition and turnover of Bruch's membrane.

Complement factor h polymorphism, inflammatory mediators, and retinal vessel diameters: the rotterdam study

PURPOSE

Retinal venular dilatation is associated with systemic inflammation. The hypothesis for the current study was that larger retinal venular diameters are related to the His allele of the Tyr402His polymorphism in the complement factor H (CFH) gene, a major inhibitor of the complement pathway. Possible effect modification by smoking and inflammatory markers was examined.

METHODS

This cross-sectional study was performed within the Rotterdam Study, a population-based study among elderly persons aged 55 years and older. The Tyr402His polymorphism of the CFH gene was genotyped in 5066 participants and retinal arteriolar and venular diameters were graded on digitized fundus transparencies.

RESULTS

Genotype frequencies were 41% in TyrTyr, 45% in TyrHis, and 14% in HisHis carriers. The His(402) allele was associated with smaller rather than larger venular diameters (age- and sex-adjusted means and standard errors [in micrometers] were 222.5 +/- 0.45 for TyrTyr, 221.9 +/- 0.43 for TyrHis, and 220.6 +/- 0.78 for HisHis carriers; P-trend = 0.03). This association was apparent only in never-smokers and was not modified by the inflammatory markers erythrocyte sedimentation rate, leukocyte count, C-reactive protein, or fibrinogen. Adjustment for cardiovascular risk factors did not change results. No associations were found with arteriolar diameters.

CONCLUSIONS

The findings do not support the hypothesis that the His(402) allele is related to larger retinal venular diameters. The association with smaller retinal venular diameters most likely is a chance finding, because it was present only among never-smokers and was not modified by inflammatory mediators of complement. These results suggest that the Tyr402His variant is not related to retinal venular diameters.

Usefulness of combining complement factor H and C-reactive protein genetic profiles for predicting myocardial infarction (from the Rotterdam Study)

Complement factor H (CFH) is an important regulator of the complement cascade. Binding of C-reactive protein (CRP) to CFH augments the ability of CFH to downregulate the effect of complement in atherosclerotic lesions. The CFH Tyr402His polymorphism has been suggested to influence the ability of CFH to bind CRP. We hypothesized that the combined presence of unfavorable CRP and CFH genetic profiles is associated with risk of myocardial infarction (MI). The Rotterdam Study is a population-based cohort study in 7,983 men and women aged > or =55 years. The CFH Tyr402His (rs1061170) polymorphism was determined (His(402) allele 37%), and using 3 tagging polymorphisms (rs1130864, rs1205, and rs3093068), CRP haplotypes were inferred (1 = CTC, 2 = TCC, 3 = CCC, 4 = CCG; frequencies of 33%, 32%, 30%, and 6%, respectively). Participants were grouped by CFH genotype (TyrTyr [reference], TyrHis, and HisHis) and CRP haplotype (haplotype 1 homozygotes [reference], haplotype 2 carriers, haplotype 3 carriers, and haplotype 4 carriers), which resulted in a total of 12 groups. CFH His(402) homozygotes who were also CRP haplotype 3 carriers had an age- and gender-adjusted hazard ratio of 5.9 (95% confidence interval 2.1 to 16.5) to develop MI compared with the reference group. In conclusion, this population-based study suggests that the combined presence of unfavorable CFH and CRP genetic profiles is associated with risk of MI.

Blood pressure, arterial stiffness, and open-angle glaucoma: the Rotterdam study

OBJECTIVE

To investigate cross-sectional associations among blood pressures (BPs), arterial stiffness, and open-angle glaucoma (OAG).

METHODS

Study participants came from the population-based Rotterdam Study. The baseline examination phase took place after an extensive home interview from March 20, 1990, to June 17, 1993, and the third phase between March 19, 1997, and December 16, 1999. Cases were classified into high-tension OAG (htOAG) and normal-tension OAG (ntOAG), according to an intraocular pressure greater than 21 mm Hg or 21 mm Hg or less. Pulse pressure was the difference between systolic and diastolic BP. Diastolic perfusion pressure was the difference between diastolic BP and the intraocular pressure; indicators of arterial stiffness were carotid-femoral pulse wave velocity and carotid distensibility. Associations were evaluated with logistic regression analysis, adjusted for age, sex, body mass index, smoking, diabetes mellitus, serum cholesterol level, and BP-lowering treatment.

RESULTS

A total of 5317 participants were included in this study. In participants with a higher pulse pressure, the prevalence of htOAG was elevated (odds ratio [OR] per standard deviation, 1.32; 95% confidence interval [CI], 1.03-1.69). In persons treated for systemic hypertension, low diastolic perfusion pressure (<50 mm Hg) was inversely associated with ntOAG (OR, 0.25; 95% CI, 0.10-0.63) and positively associated with htOAG (OR, 4.68; 95% CI, 1.29-17.01). The lowest tertile of carotid distensibility compared with the highest had an OR for htOAG of 2.84 (95% CI, 0.99-8.10; P=.05).

CONCLUSIONS

We found that htOAG was associated with high pulse pressure, possibly with increased carotid arterial stiffness, and, only in persons treated for systemic hypertension, with low diastolic perfusion pressure. In these persons, ntOAG was associated with high diastolic BP, whereas the association between ntOAG and low diastolic perfusion pressure was inverted.

C-terminal truncations in human 3′-5′ DNA exonuclease TREX1 cause autosomal dominant retinal vasculopathy with cerebral leukodystrophy

Autosomal dominant retinal vasculopathy with cerebral leukodystrophy is a microvascular endotheliopathy with middle-age onset. In nine families, we identified heterozygous C-terminal frameshift mutations in TREX1, which encodes a 3'-5' exonuclease. These truncated proteins retain exonuclease activity but lose normal perinuclear localization. These data have implications for the maintenance of vascular integrity in the degenerative cerebral microangiopathies leading to stroke and dementias.

Retinal vessel diameters and the role of inflammation in cerebrovascular disease

Retinal vessels may provide a way to study the cerebral microcirculation. In particular, larger retinal venular diameters have been associated with cerebrovascular disease. An inflammatory response may underlie this association. In a population-based cohort study among 5,279 participants aged 55 years or older with graded retinal vessel diameters, we observed that greater serum levels of C-reactive protein and fibrinogen and greater lipoprotein-associated phospholipase A(2) activity were strongly associated with larger venular diameters. Weaker associations were found with arteriolar diameters. Our findings support the hypothesis that larger retinal venular diameters reflect systemic inflammation and suggest that inflammation is involved in cerebrovascular disease.

Systemic antihypertensive medication and incident open-angle glaucoma

PURPOSE

To determine the association between systemic antihypertensive medication and incident open-angle glaucoma.

DESIGN

Prospective population-based cohort study.

PARTICIPANTS

The study population consisted of a subset of 3842 participants of the Rotterdam Study for whom data from identical ophthalmologic examinations at baseline and follow-up were available.

METHODS

Use of antihypertensive medication was registered over an average follow-up period of 6.5 years. Associations between incident open-angle glaucoma and antihypertensive medication were assessed using multivariate logistic regression models adjusted for age, gender, duration of follow-up, intraocular pressure, intraocular pressure-lowering medication, and cardiovascular disease.

MAIN OUTCOME MEASURES

Odds ratios of associations between incident open-angle glaucoma and use of antihypertensive medication.

RESULTS

During follow-up, there were 87 incident cases of open-angle glaucoma. Participants using calcium channel antagonists had a 1.8-fold (95% confidence interval [CI], 1.04-3.2; P = 0.037) higher risk of developing incident open-angle glaucoma. beta-Blockers were associated with a nonsignificant risk reduction (odds ratio, 0.6; 95% CI, 0.3-1.02; P = 0.060). None of the other classes of antihypertensives was significantly associated with incident open-angle glaucoma.

CONCLUSIONS

These data suggest that use of calcium channel antagonists is associated with open-angle glaucoma, but this requires confirmation. These results do not support the use of calcium channel antagonists for the treatment of normal-tension glaucoma.

L1 retrotransposition can occur early in human embryonic development

L1 elements are autonomous retrotransposons that can cause hereditary diseases. We have previously identified a full-length L1 insertion in the CHM (choroideremia) gene of a patient with choroideremia, an X-linked progressive eye disease. Because this L1 element, designated L1(CHM), contains two 3'-transductions, we were able to delineate a retrotransposition path in which a precursor L1 on chromosome 10p15 or 18p11 retrotransposed to chromosome 6p21 and subsequently to the CHM gene on chromosome Xq21. A cell culture retrotransposition assay showed that L1(CHM) is one of the most active L1 elements in the human genome. Most importantly, analysis of genomic DNA from the CHM patient's relatives indicated somatic and germ-line mosaicism for the L1 insertion in his mother. These findings provide evidence that L1 retrotransposition can occur very early in human embryonic development.

Estrogen receptor alpha gene polymorphisms associated with incident aging macula disorder

PURPOSE

It has been suggested that early menopause increases the risk of aging-macula disorder (AMD), the major cause of incurable blindness with a dry and wet late subtype, and that exposure to endogenous or postmenopausal exogenous estrogens reduces this risk. This study was undertaken to investigate whether genetic variations in the estrogen receptor alpha (ESR1) gene are associated with incident AMD.

METHODS

In the Rotterdam Study, a prospective population-based cohort study of participants aged 55 years and older, associations between ESR1 PvuII-XbaI haplotypes and incident early or late AMD were studied in 4571 participants after a mean follow-up time of 7.7 years. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs), with adjustment for the most common confounders.

RESULTS

ESR1 PvuII-XbaI haplotype 1 was a risk factor for late AMD. Persons with two copies of haplotype 1 were at 3.20 (95% CI, 1.47-6.99) times higher risk for late AMD than noncarriers of haplotype 1, after adjustment for age and sex. This increase was more pronounced for wet AMD (hazard ratio [HR] 4.29; 95% CI, 1.47-12.49) after adjustment for age, sex, smoking, and complement factor H genotype. Correction for additional confounders, including age at menopause, use of hormone replacement therapy, blood pressure, and body mass index did not essentially alter the findings.

CONCLUSIONS

Persons with one or two copies of ESR1 PvuII-XbaI haplotype 1 have an increased risk of late AMD, especially of the wet form.

Atherosclerosis, C-Reactive Protein, and Risk for Open-Angle Glaucoma: The Rotterdam Study

PURPOSE

To test the hypotheses that atherosclerosis and elevated serum C-reactive protein (CRP) levels are risk factors for open-angle glaucoma (OAG).

METHODS

In a prospective, population-based cohort study, all participants 55 years and older and at risk for incident OAG underwent, at baseline (1990-1993) and at follow-up (1997-1999), the same ophthalmic examination, including visual field testing and optic disc photography. Baseline atherosclerosis was assessed by means of echography of the carotid arteries, abdominal x-ray examination, and ankle-arm index; baseline serum CRP levels were used in the analyses. The diagnosis of OAG was based on an algorithm using optic disc measures and visual field loss. Odds ratios of OAG were computed with logistic regression analyses. Risk factors were categorized in tertiles and according to standard deviation.

RESULTS

After a mean follow-up of 6.5 years, incident OAG was diagnosed in 87 of 3842 (2.3%) participants at risk for OAG. Carotid artery plaques, carotid intima-media thickness, aortic calcifications, ankle-arm index, and CRP levels were not significant risk factors for OAG. The odds ratio, given for the highest and lowest tertiles, for carotid plaques was 1.43 (95% confidence interval [CI], 0.68-2.99), for carotid intima-media thickness 0.86 (95% CI, 0.47-1.57), for aortic calcifications 1.02 (95% CI, 0.60-1.75), for ankle-arm index 0.69 (95% CI, 0.38-1.25), and for CRP 1.19 (95% CI, 0.68-2.07).

CONCLUSIONS

In this prospective, population-based study, neither atherosclerosis nor serum CRP level was an important risk factor for OAG.

An igf-I gene polymorphism modifies the risk of diabetic retinopathy

The role of IGF-I in the pathogenesis of diabetic retinopathy is unclear. We studied, prospectively, the relationship between an IGF-I gene polymorphism, retinal vessel diameters, and incident diabetic retinopathy in subjects with impaired glucose tolerance (IGT) or type 2 diabetes. In all 5,505 participants of the population-based Rotterdam Study (775 with IGT, 394 with type 2 diabetes, and 4,336 control subjects), fundus color transparencies were taken at baseline (between 1990 and 1993) and at follow-up (from 1997 to 1999). The wild-type genotype (i.e., carriers of the 192- or 194-bp alleles) was present in 72.7% of the participants, while 27.3% were variant carriers. Variant carriers with IGT or type 2 diabetes appeared to have larger retinal arteriolar and venular diameters at baseline than individuals with the wild-type genotype, but these differences did not reach statistical significance. This trend was especially observed in subjects who developed retinopathy at follow-up. In variant carriers with IGT/diabetes, an increase (odds ratio 1.8 [95% CI 1.0-3.2]; P = 0.04) in the risk of retinopathy was observed compared with participants with the wild-type genotype. In conclusion, our findings suggest that this IGF-I gene polymorphism is associated with an increased risk of diabetic retinopathy.

Is diabetes mellitus a risk factor for open-angle glaucoma? The Rotterdam Study

PURPOSE

To investigate whether diabetes mellitus is a risk factor for open-angle glaucoma (OAG).

DESIGN

Prospective population-based cohort study.

PARTICIPANTS

Participants ages > or =55 years from the Rotterdam Study, The Netherlands.

METHODS

Participants at risk for incident OAG (iOAG) underwent at baseline (1990-1993) and follow-up (1997-1999) the same ophthalmic examination including intraocular pressure (IOP) measurement, visual field testing, and simultaneous stereo optic disc photography. At baseline, diabetes mellitus was defined as the use of antidiabetic medication and/or a random or postload glucose value > or =11.1 mmol/l. The diagnosis of OAG was made with an algorithm based on optic disc measures and visual fields, independent of the IOP.

MAIN OUTCOME MEASURE

Incident OAG.

RESULTS

In total, 3837 participants without OAG at baseline were reexamined. After a mean follow-up time of 6.5 years, iOAG developed in 87 persons. The relative risk of iOAG associated with baseline diabetes was 0.82 (0.33-2.05). After adjustment for age, gender, follow-up time, IOP, IOP-lowering treatment, body mass index, and systemic hypertension, the relative risk of iOAG was 0.65 (0.25-1.64).

CONCLUSIONS

In this prospective population-based study, diabetes mellitus was not a risk factor for OAG.

Complement factor H polymorphism, complement activators, and risk of age-related macular degeneration

CONTEXT

The evidence that inflammation is an important pathway in age-related macular degeneration (AMD) is growing. Recent case-control studies demonstrated an association between the complement factor H (CFH) gene, a regulator of complement, and AMD.

OBJECTIVES

To assess the associations between the CFH gene and AMD in the general population and to investigate the modifying effect of smoking, serum inflammatory markers, and genetic variation of C-reactive protein (CRP).

DESIGN, SETTING, AND PARTICIPANTS

Population-based, prospective cohort study of individuals aged 55 years or older (enrollment between March 20, 1990, and July 31, 1993, and 3 follow-up examinations that were performed between September 1, 1993, and December 31, 2004) in Rotterdam, the Netherlands. The CFH Y402H polymorphism was determined in a total of 5681 individuals. Information on smoking, erythrocyte sedimentation rate, CRP serum levels, and haplotypes of the CRP gene were assessed at baseline.

MAIN OUTCOME MEASURES

All severity stages of prevalent and incident AMD, graded according to the international classification and grading system for AMD.

RESULTS

The frequency of CFH Y402H was 36.2% (4116/11,362 alleles). At baseline, there were 2062 persons (36.3%) with any type of AMD (prevalent cases), including 78 (1.4%) with late AMD (stage 4). During follow-up (mean, 8 years; median, 10 years), 1649 (35.5%) of 4642 participants progressed to a higher stage of AMD (incident cases), including 93 (5.6%) who developed late AMD. The odds ratio (OR) of AMD increased in an allele-dose manner with 2.00 (95% confidence interval [CI], 1.56-2.55) for stage 2 AMD, 4.58 (95% CI, 2.82-7.44) for stage 3 AMD, and 11.02 (95% CI, 6.82-11.81) for stage 4 (late, vision threatening) AMD for homozygous persons. Cumulative risks calculated by Kaplan-Meier analysis of late AMD by age 95 years were 48.3% for homozygotes, 42.6% for heterozygotes, and 21.9% for noncarriers. The population-attributable risk for CFH Y402H was 54.0%. Elevated erythrocyte sedimentation rates further increased the OR to 20.2 (95% CI, 9.5-43.0), elevated serum CRP levels to 27.7 (95% CI, 10.7-72.0), and smoking to 34.0 (95% CI, 13.0-88.6) for homozygotes compared with noncarriers without these determinants. The CRP haplotypes conferring high levels of CRP significantly increased the effect of CFH Y402H (P<.01).

CONCLUSIONS

The CFH Y402H polymorphism may account for a substantial proportion of AMD in individuals similar to those in the Rotterdam Study and may confer particular risk in the presence of environmental and genetic stimulators of the complement cascade.

Late-Onset Retinoblastoma in a Well-Functioning Fellow Eye

PURPOSE

To describe the documented growth, clinical course, and histopathology of retinoblastomas in an untreated and otherwise normal right eye of a 27-year-old white male with a g.153211T>A (p.Tyr606X) mutation in the retinoblastoma 1 gene, whose left eye was enucleated at age 2 years for 2 retinoblastomas.

DESIGN AND PARTICIPANTS

Retrospective interventional case report.

INTERVENTIONS

Over the years, the right eye was irradiated twice and underwent trans-pars plana vitrectomy, transscleral cryocoagulation, argon laser photocoagulation of tumors and their feeder vessels, extracapsular cataract extraction with posterior chamber lens implantation, and neodymium:yttrium-aluminum-garnet laser treatment of after-cataract in the form of Elschnig's pearls. Finally, the patient received combination chemotherapy with etoposide, methotrexate, actinomycin D, cisplatin, and vincristine.

RESULTS

The eye finally had to be removed 12 years later due to tumor recurrences and seeding, pseudohypopyon, and elevated intraocular pressure. Histopathology showed microcellular retinoblastoma cells in the anterior chamber angle and trabecular meshwork without subconjunctival extension and in the nasal ciliary body, pars plana, internal limiting membrane, and optic nerve head anterior to the cribriform plate. The patient is without local or systemic recurrences at age 50, 11 years after the last eye was enucleated.

CONCLUSIONS

This report shows that retinoblastoma patients may have tumor growth in their fellow eye 25 years after the first eye and also that Elschnig's after-cataract pearls still can arise after irradiation of a lens with 45 Gy.

Epidemiology of neurological diseases in elderly people: what did we learn from the Rotterdam Study?

The Rotterdam Study is a prospective cohort study that has been ongoing since 1990 in the city of Rotterdam, the Netherlands, among 7983 people aged 55 years or older. One part of the study targets neurological diseases, others deal with cardiovascular, ophthalmological, and endocrine diseases. The findings of the Rotterdam Study have been presented in some . Here we give the reasons for the study and its design, and present a summary of what has been learned about the frequencies and causes of neurological diseases. Perhaps the most important message from the Rotterdam Study is the great potential for prevention or postponement of neurological diseases in elderly people. The time for preventive nihilism is over.

Prevalence of age-related maculopathy in older Europeans: the European Eye Study (EUREYE)

OBJECTIVE

To estimate the prevalence of age-related maculopathy in an older population from 7 European countries.

METHODS

Randomly sampled people 65 years and older were invited to an eye examination in centers across 7 European countries (Norway, Estonia, United Kingdom, France, Italy, Greece, and Spain). Fundus images of each eye were graded at a single reading center. Prevalence rates were calculated for stage of age-related maculopathy with 95% confidence intervals (CIs) estimated for clustered data.

RESULTS

Of 5040 participants (45% response rate), 4753 (2128 men and 2625 women) had gradable fundus images. The prevalences were grade 0, 47.59% (95% CI, 43.53%-51.65%); grade 1, 36.48% (95% CI, 32.66%-40.30%); grade 2, 10.14% (95% CI, 8.92% to 11.37%); grade 3, 2.46% (95% CI, 1.79%-3.13%); and grade 4 (age-related macular degeneration [AMD]), 3.32% (95% CI, 2.52%-4.13%) and large drusen only (> or = 125 microm), 15.41% (95% CI, 13.61%-17.21%). The prevalence of geographic atrophic AMD was 1.2% (95% CI, 0.8%-1.7%) and of neovascular AMD, 2.3% (95% CI, 1.7%-2.9%). The prevalence of bilateral AMD was 1.4% (95% CI, 1.0%-1.8%).

CONCLUSION

Age-specific prevalences of age-related maculopathy in the European Eye Study (EUREYE) are similar to other population-based studies in Western populations.

ABCC6 and pseudoxanthoma elasticum

ABCC6 belongs to the adenosine triphosphate-binding cassette (ABC) gene subfamily C. This protein family is involved in a large variety of physiological processes, such as signal transduction, protein secretion, drug and antibiotic resistance, and antigen presentation [Kool et al. (1999) 59:175-182; Borst and Elferink (2002) 71:537-592]. ABCC6 is primarily and highly expressed in the liver and kidney [Kool et al. (1999) 59:175-182; Bergen et al. (2000) 25:228-2231]. The precise physiological function and natural substrate(s) transported by ABCC6 are unknown, but the protein may be involved in active transport of intracellular compounds to the extracellular environment [Kool et al. (1999) 59:175-182] [Scheffer et al. (2002) 82:515-518]. Recently, it was shown that loss of function mutations in ABCC6 cause pseudoxanthoma elasticum (PXE) [Bergen et al. (2000) 25:228-2231; Le Saux et al. (2000) 25:223-227]. PXE is an autosomal recessively inherited multi-organ disorder [Goodman et al. (1963) 42:297-334; Lebwohl et al. (1994) 30:103-107]. PXE is primarily associated with the accumulation of mineralized and fragmented elastic fibers of the connective tissue in the skin [Neldner (1988) 6:1-159], Bruch's membrane in the retina [Hu et al. (2003) 48:424-438], and vessel walls [Kornet et al. (2004) 30:1041-1048]. PXE patients usually have skin lesions and breaks in Bruch's membrane of the retina (angioid streaks). Also, a variety of cardiovascular complications has been observed [Hu et al. (2003) 48:424-438]. Recently, a mouse model for PXE was created by targeted disruption of Abcc6 [Gorgels et al. (2005) 14:1763-1773; Klement et al. (2005) 25:8299-8310], which may be useful to elucidate the precise function of Abcc6 and to develop experimental therapies.

A common polymorphism in the complement factor H gene is associated with increased risk of myocardial infarction: the Rotterdam Study

OBJECTIVES

This study was designed to investigate the association between a common polymorphism (Tyr402His, rs1061170) in the complement factor H (CFH) gene and risk of coronary heart disease.

BACKGROUND

The evidence that inflammation is an important mechanism in atherogenesis is growing. C-reactive protein (CRP), complement factors, and complement regulatory factors have all been linked to coronary heart disease. The CFH gene is an important regulator of the alternative complement cascade. We investigated its association with coronary heart disease.

METHODS

The study was embedded in the Rotterdam Study, a prospective population-based study among men and women aged 55 years and over. A total of 5,520 participants without history of coronary heart disease was genotyped for the Tyr402His polymorphism of the CFH gene. Cox proportional hazards analysis was used to determine risk of myocardial infarction for Tyr402His genotypes.

RESULTS

Mean age among participants was 69.5 years (SD 9.1 years). The overall frequency of the His allele was 36%; genotype frequencies were 41%, 45%, and 14% for TyrTyr, TyrHis, and HisHis, respectively. During a mean follow-up period of 8.4 years, 226 myocardial infarctions occurred. After adjustment for age, gender, established cardiovascular risk factors, and CRP level, HisHis homozygotes had a hazard ratio of 1.77 (95% confidence interval 1.23 to 2.55) for myocardial infarction. Total cholesterol level, diabetes mellitus, and smoking modified the effect. The Tyr402His polymorphism was not associated with established cardiovascular risk factors or CRP level.

CONCLUSIONS

Our data suggest that the CFH gene determines susceptibility to myocardial infarction. This finding underscores the importance of the alternative complement system in cardiovascular disease.

Retinal Vessel Diameters and Risk of Hypertension

Generalized retinal arteriolar narrowing is an important sign of systemic hypertension, and a lower arteriolar:venular diameter ratio predicts the risk of hypertension. We investigated whether this association was based on arteriolar or venular diameters or both. This study was based on the prospective population-based Rotterdam Study (1990-1993) and included 1900 participants (> or =55 years of age) of whom 739 persons had normal blood pressure (systolic <120 mm Hg and diastolic <80 mm Hg) and 1161 prehypertension (systolic 120 to 139 mm Hg or diastolic 80 to 89 mm Hg). For each participant, retinal arteriolar and venular diameters were measured on digitized images of 1 eye. After a mean follow-up of 6.6 years, 808 persons developed hypertension, defined as either systolic blood pressure > or =140 mm Hg or diastolic blood pressure > or =90 mm Hg or use of antihypertensive medication. Adjusted for age, gender, follow-up time, body mass index, smoking, diabetes mellitus, total and high-density lipoprotein cholesterol, C-reactive protein, and intima-media thickness, arteriolar narrowing was associated with an increased risk of hypertension (odds ratio per SD: 1.38; 95% CI, 1.23 to 1.55); for venular narrowing this was less striking (OR: 1.17; 95% CI, 1.04 to 1.32). Each SD decrease in the arteriolar:venular diameter ratio significantly increased the risk of hypertension by 24%. To examine the effect of baseline blood pressure, we stratified persons into those with "normal blood pressure" or "prehypertension." Within these strata, arteriolar narrowing was still related to incident hypertension. These data show that both retinal arteriolar and venular narrowing may precede the development of systemic hypertension.

Retinal vessel diameters and risk of impaired fasting glucose or diabetes: the Rotterdam study

The association between a smaller retinal arteriolar-to-venular ratio (AVR) and incident diabetes may be due to arteriolar narrowing, venular dilatation, or both. We investigated associations between baseline vessel diameters and incident impaired fasting glucose or diabetes in a population-based cohort (aged > or =55 years). Baseline retinal vessel diameters (1990-1993) were measured on digitized images of 2,309 subjects with a normal glucose tolerance test (postload glucose <7.8 mmol/l). At follow-up (1997-1999), impaired fasting glucose was defined as 6.1-7.0 mmol/l and diabetes as > or =7.0 mmol/l and/or antidiabetic medication use. Odds ratios (ORs) per SD increase in venular diameters were 1.13 (95% CI 1.00-1.29) for impaired fasting glucose and 1.09 (0.90-1.33) for diabetes. ORs per SD decrease in arteriolar diameters were 1.12 (0.98-1.27) and 1.08 (0.89-1.31) and per SD decrease in AVR were 1.29 (1.13-1.46) and 1.19 (0.98-1.45). After adjustment for cardiovascular risk factors, the associations were unaltered for venules and disappeared for arterioles. After stratification on age, associations between venular dilatation and impaired fasting glucose (1.23 [1.02-1.47]) or diabetes (1.18 [0.89-1.56]) were mainly present in participants aged <70 years. In conclusion, in our study, the risk of impaired fasting glucose and diabetes with AVR was explained by venular dilatation rather than arteriolar narrowing, warranting more focus on the causes of this dilatation.

Dietary intake of antioxidants and risk of age-related macular degeneration

CONTEXT

Age-related macular degeneration (AMD) is the most prevalent cause of irreversible blindness in developed countries. Recently, high-dose supplementation with beta carotene, vitamins C and E, and zinc was shown to slow the progression of AMD.

OBJECTIVE

To investigate whether regular dietary intake of antioxidants is associated with a lower risk of incident AMD.

DESIGN

Dietary intake was assessed at baseline in the Rotterdam Study (1990-1993) using a semiquantitative food frequency questionnaire. Incident AMD until final follow-up in 2004 was determined by grading fundus color transparencies in a masked way according to the International Classification and Grading System.

SETTING

Population-based cohort of all inhabitants aged 55 years or older in a middle-class suburb of Rotterdam, the Netherlands.

PARTICIPANTS

Of 5836 persons at risk of AMD at baseline, 4765 had reliable dietary data and 4170 participated in the follow-up.

MAIN OUTCOME MEASURE

Incident AMD, defined as soft distinct drusen with pigment alterations, indistinct or reticular drusen, geographic atrophy, or choroidal neovascularization.

RESULTS

Incident AMD occurred in 560 participants after a mean follow-up of 8.0 years (range, 0.3-13.9 years). Dietary intake of both vitamin E and zinc was inversely associated with incident AMD. The hazard ratio (HR) per standard deviation increase of intake for vitamin E was 0.92 (95% confidence interval [CI], 0.84-1.00) and for zinc was 0.91 (95% CI, 0.83-0.98). An above-median intake of all 4 nutrients, beta carotene, vitamin C, vitamin E, and zinc, was associated with a 35% reduced risk (HR, 0.65; 95% CI, 0.46-0.92) of AMD. Exclusion of supplement users did not affect the results.

CONCLUSION

In this study, a high dietary intake of beta carotene, vitamins C and E, and zinc was associated with a substantially reduced risk of AMD in elderly persons.

Reduced melanoma-related mortality in uveal melanoma by preenucleation radiotherapy

BACKGROUND

Radiotherapy of an eye before enucleation, so called preenucleation radiotherapy (PER), of patients with uveal melanoma was initiated to reduce enucleation-induced systemic metastasis. Earlier studies with a short follow-up period have not demonstrated a significant effect on survival.

OBJECTIVE

To study the effect of PER on melanoma-related mortality after more than 9 years of follow-up.

DESIGN

In a prospective study, 167 patients with uveal melanoma were treated between 1978 and 1992 by irradiation with 800 rad (8 Gy) given in 2 fractions 2 days before enucleation. A group of 108 patients with uveal melanoma treated between 1971 and 1992 by enucleation only in the same hospital served as a historical control group. Patients were followed up until December 2002 or death.

RESULTS

Melanoma-related death occurred in 32.3% of the PER-treated group and in 40.7% of the enucleation only group. Mean follow-up was 9.25 years. After 48 months of follow-up, a significant difference in survival became evident in favor of the PER group. The estimated 15-year survival rates for patients with melanoma in the PER group and enucleation only group were 63.7% and 51.0%, respectively. For patients dying of all causes, these percentages were 47.5% and 25.2%, respectively. In both groups, women had a better prognostic outcome than men.

CONCLUSION

This study suggests that PER improves long-term survival in patients with uveal melanoma.

Incidence of open-angle glaucoma in a general elderly population: the Rotterdam Study

PURPOSE

To determine the incidence of open-angle glaucoma (OAG) in a general elderly white population.

DESIGN

Population-based cohort study.

PARTICIPANTS

Participants 55 years and older from the Rotterdam Study, The Netherlands.

METHODS

Participants at risk for incident OAG underwent at baseline (1990-1993) and follow-up (1997-1999) the same ophthalmic examination, including measurement of intraocular pressure, visual field testing, and stereo optic disc photography. The diagnosis of probable or definite OAG was made with an algorithm based on optic disc parameters and on visual field testing, independent of the intraocular pressure.

MAIN OUTCOME MEASURES

Five-year risk and incidence rates of OAG.

RESULTS

In total, 3842 participants were examined (participation rate at follow-up, 78%). After a mean follow-up time of 6.5 years, probable (n = 58) or definite OAG (n = 29) developed in 87 persons. The 5-year risk of probable OAG was 1.2% and that of definite OAG 0.6%, and the rate rose for both together from 1% at age 60 years to approximately 3% at age 80 years. Bilateral OAG occurred 5 times more often after than before age 75 years. In participants with prevalent OAG in 1 eye, the 5-year risk of OAG in the fellow eye was 5 times higher than in fellow eyes of non-OAG eyes. Only 37% of the incident cases received treatment for OAG at the time of the reexamination.

CONCLUSIONS

The incidence of OAG rose significantly with age. Most of the patients with incident OAG were unaware of having OAG.

VAMP5 and VAMP8 are most likely not involved in primary open-angle glaucoma

PURPOSE

To select and characterize novel POAG disease genes. On the basis of genetic position (GLC1B), expression in the optic nerve, and biochemical function (targeted membrane transport processes), we selected the human VAMP5 and VAMP8 (encoding vesicle-associated membrane proteins 5 and 8) as potential candidate disease genes for POAG. We subsequently analyzed whether or not sequence changes in VAMP5 or VAMP8 were implicated in POAG.

METHODS

Genomic DNA samples from 90 POAG cases and 60 controls were screened by denaturing high performance liquid chromatography of fragments amplified by the polymerase chain reaction. Direct sequencing identified nucleotide changes.

RESULTS

No nonsynonymous rare sequence variants were found in VAMP5 or VAMP8. In VAMP5, three previously identified and five new single nucleotide polymorphisms (SNPs) were found. In VAMP8, four known and two new SNPs were detected. All new SNPs did not appear to change gene function or alter gene splicing. No significant differences were found between the allele frequencies in POAG cases and controls.

CONCLUSIONS

Our findings indicate that VAMP5 and VAMP8 are not involved in POAG in the Dutch population.

Disruption of Abcc6 in the mouse: novel insight in the pathogenesis of pseudoxanthoma elasticum

Pseudoxanthoma elasticum (PXE) is a heritable disorder of connective tissue, affecting mainly skin, eye and the cardiovascular system. PXE is characterized by dystrophic mineralization of elastic fibres. The condition is caused by loss of function mutations in ABCC6. We generated Abcc6 deficient mice (Abcc6-/-) by conventional gene targeting. As shown by light and electron microscopy Abcc6-/- mice spontaneously developed calcification of elastic fibres in blood vessel walls and in Bruch's membrane in the eye. No clear abnormalities were seen in the dermal extracellular matrix. Calcification of blood vessels was most prominent in small arteries in the cortex of the kidney, but in old mice, it occurred also in other organs and in the aorta and vena cava. Newly developed monoclonal antibodies against mouse Abcc6 localized the protein to the basolateral membranes of hepatocytes and the basal membrane in renal proximal tubules, but failed to show the protein at the pathogenic sites. Abcc6-/- mice developed a 25% reduction in plasma HDL cholesterol and an increase in plasma creatinine levels, which may be due to impaired kidney function. No changes in serum mineral balance were found. We conclude that the phenotype of the Abcc6-/- mouse shares calcification of elastic fibres with human PXE pathology, which makes this model a useful tool to further investigate the aetiology of PXE. Our data support the hypothesis that PXE is in fact a systemic disease.

Retinal vessel diameters and the risk of incident age-related macular disease: the Rotterdam Study

PURPOSE

To study the relationship between retinal vessel diameters and incident age-related macular disease (iAMD).

DESIGN

Prospective population-based cohort study.

PARTICIPANTS

Persons (55 years and older) from the Rotterdam Study, who participated at the baseline (1990-1993) and 1 of 2 follow-up examinations (1993-1994 and 1997-1999).

METHODS

In the current analysis, 4345 participants who were free of AMD at baseline and had gradable macular transparencies at both baseline and follow-up examination were included. Also, arteriolar and venular diameters were measured on digitized baseline images. Stereoscopic transparencies of the macular region were graded according to the International Classification and Grading System for AMD. Incidence of AMD was defined as the development of soft distinct drusen with pigmentary changes or indistinct or reticular drusen with or without pigmentary changes (early iAMD) or atrophic or neovascular AMD (late iAMD). Logistic regression models were used to assess these associations, adjusting for age, gender, and follow-up time and, additionally, for smoking, body mass index, intima-media thickness, systolic blood pressure, and total and high-density lipoprotein cholesterol levels.

MAIN OUTCOME MEASURE

Incidence of AMD.

RESULTS

After a mean follow-up time of 5.2 years, a total of 374 persons developed early and late iAMD. Neither arteriolar nor venular diameters were related to the risk of iAMD. The odds ratio (OR) per standard deviation (SD) decrease in arteriolar diameter was 1.03 (95% confidence interval [CI], 0.93-1.15), and the OR per SD increase in venular diameter was 1.04 (95% CI, 0.93-1.16). After categorizing the retinal vessel diameters into quintiles, there was no trend. After stratifying on age, only persons 75 years and older with smaller arteriolar diameters were at a borderline significant increased risk of iAMD: OR/SD decrease in arteriolar diameters adjusted for age, gender, follow-up time, and other cardiovascular risk factors, 1.24 (95% CI, 0.94-1.63).

CONCLUSION

Overall retinal vessel diameters were not related to the risk of iAMD in this general elderly population.

Retinal Vessel Diameters and Incident Open-Angle Glaucoma and Optic Disc Changes: The Rotterdam Study

PURPOSE

It remains unclear whether reduced retinal blood flow and smaller arterioles, reported to exist in patients with open-angle glaucoma (OAG), are a cause or a consequence of ganglion cell loss. We examined whether baseline retinal vessel diameters were related to incident (i)OAG or incident optic disc changes in a population-based sample.

METHODS

In the prospective population-based Rotterdam Study, baseline diameters of retinal arterioles and venules (1990-1993) were measured in digitized images of 3469 persons (aged 55 years and older) at risk for OAG. The follow-up examinations took place from 1997 to 1999. iOAG was based on the presence of incident glaucomatous visual field loss and/or incident glaucomatous optic neuropathy. Changes in neuroretinal rim, cup area, or vertical cup-to-disc ratio were calculated with a semiautomated image analyzer in 2782 persons.

RESULTS

After a mean follow-up time of 6.5 years, 74 participants had iOAG. At baseline, the mean arteriolar diameter was 147.5 +/- 14.2 microm (SD) and the venular, 222.9 +/- 20.0 microm. Neither arteriolar diameters (odds ratio [OR] per SD decrease: 0.82; 95% confidence interval [CI]: 0.66-1.03) nor venular ones (OR per SD increase: 1.20; 95% CI: 0.95-1.53) were significantly related to iOAG. Baseline retinal vessel diameters did not predict changes in the optic disc. Additional adjustment for cardiovascular risk factors did not alter these results.

CONCLUSIONS

The data show that baseline retinal vessel diameters did not influence the risk of iOAG or incident optic disc changes. These data provide no evidence for a retinal vascular role in the pathogenesis of OAG.

Heterogeneity of the genetic risk in age-related macular disease: a population-based familial risk study

OBJECTIVE

To assess the extent of heterogeneity of the genetic risk of age-related macular disease (AMD) among families.

DESIGN

Case-controlled population-based familial aggregation study.

PARTICIPANTS

Participants comprised 190 first-degree relatives of 65 case probands and 347 relatives of 100 control probands. All probands had been identified from the baseline phase of the Rotterdam Study in The Netherlands.

METHODS

A family score was computed for each family based on the presence and type of macular disease, the expected risk of disease, and the number, extent of kinship, and age of all family members.

MAIN OUTCOME MEASURES

Presence and stage of AMD as diagnosed on fundus photographs, family score, and logistic regression coefficient.

RESULTS

The family score of case families showed a peak of approximately 0 with a skewed tail (14% of families) of higher than expected risks of disease toward a maximum of 2.9. The family score of control families centered on 0, apart from 1 outlier. The risk of AMD increased significantly with higher family scores (beta = 1.34; P<0.001).

CONCLUSIONS

The heterogeneity of genetic risk among AMD families is considerable, and the proportion of high-risk families is relatively small. The family score method is relevant for genetic counseling as well as for implementation in studies of genetic dissection of AMD.

Causes of Incident Visual Field Loss in a General Elderly Population

OBJECTIVE

To determine the incidence and causes of visual field loss (VFL) in a general elderly population.

METHODS

Central visual fields of both eyes were examined with suprathreshold perimetry in 3761 persons aged 55 years or older and free of VFL at baseline from the population-based Rotterdam Study. Goldmann perimetry was performed to confirm suprathreshold VFL. Causes of incident VFL (iVFL) were assessed based on all available ophthalmologic and neurological examination data and medical records.

RESULTS

After a mean follow-up time of 6.3 years, 175 persons developed VFL. The overall incidence rate of iVFL was 7.4 per 1000 person-years, increasing to 21.1 per 1000 person-years in those aged 80 years and older. Glaucoma was the leading cause of iVFL in all age categories. The overall incidence of glaucomatous VFL was 2.0 per 1000 person-years.

CONCLUSIONS

The incidence of all VFL increased 5-fold between 55 years and 80 years of age or older. After glaucoma, stroke was the second most common cause of iVFL in persons younger than 75 years, followed by age-related macular degeneration and retinal vascular occlusive disease.

Does autosomal dominant pseudoxanthoma elasticum exist?

Pseudoxanthoma elasticum (PXE) is a progressive disorder of elastic fibers in skin, eyes, and arterial walls. It is caused by mutations in the ABCC6 gene. Most patients are sporadic cases. The majority of familial cases show autosomal recessive (AR) inheritance, but autosomal dominant (AD) inheritance has also been reported. We reviewed the literature on AD PXE and we studied in detail, both clinically and by DNA studies, a selection of potentially AD pedigrees from our patient population consisting of 59 probands and their family members. Individuals were considered to have definite PXE if they had two of the following three criteria: characteristic ophthalmologic signs, characteristic dermatologic signs, and a positive skin biopsy. In the literature we found only three families with definite PXE in two successive generations and no families with definite PXE in three or more generations. Our own data set comprised three putative AD families. Extensive DNA studies revealed a mutation in only one ABCC6 allele in the patients of these families. Only one of our families showed definite PXE in two generations. Linkage studies revealed that pseudodominance was unlikely in this family. In the other two families AD PXE could not be confirmed after extensive clinical examinations and application of our criteria, since definite PXE was not present in two or more generations.

CONCLUSION

the inheritance pattern in PXE usually is AR. Part of the phenotype in family members of PXE patients might be due to expression in heterozygous carriers of an AR disease. AD inheritance in PXE may exist, but is both after careful literature study and in our patient material much rarer than previously thought.

Efficient Molecular Diagnostic Strategy for ABCC6 in Pseudoxanthoma Elasticum

Pseudoxanthoma elasticum (PXE) is a hereditary disorder of connective tissue with skin, cardiovascular, and visual involvement. In familial cases, PXE usually segregates in an autosomal recessive fashion. The aim of this manuscript is to describe an efficient strategy for DNA diagnosis of PXE. The two most frequent mutations, R1141X and an ABCC6 del exons 23-29, as well as a core set of mutations, were identified by restriction enzyme digestion and size separation on agarose gels. Next, in the remaining patient group in which only one or no mutant allele was found, the complete coding sequence was analyzed using denaturing high-performance liquid chromatography (dHPLC). All variations found were confirmed by direct DNA sequencing. Finally, Southern blot was used to investigate the potential presence of small or large deletions. Twenty different mutations, including two novel mutations in the ABCC6 gene, were identified in 80.3% of the 76 patients, and 58.6% of the 152 ABCC6 alleles analyzed. With this strategy, 70 (78.7%) out of 89 mutant alleles could be detected within a week. We conclude that this strategy leads to both reliable and time-saving screening for mutations in the ABCC6 gene in sporadic cases and in families with PXE.

Are retinal arteriolar or venular diameters associated with markers for cardiovascular disorders? The Rotterdam Study

PURPOSE

A lower retinal arteriolar-to-venular ratio (AVR) has been suggested to reflect generalized arteriolar narrowing and to predict the risk of cardiovascular diseases. The contribution of the separate arteriolar and venular diameters to this AVR is unknown. Thus, associations between retinal arteriolar and venular diameters, and the AVR on the one hand and blood pressure, atherosclerosis, inflammation markers, and cholesterol levels on the other were examined in the Rotterdam Study.

METHODS

In this cross-sectional population-based study, for one eye of each subject (> or =55 years; n = 5674), retinal arteriolar and venular diameters (in micrometers) of the blood columns were summed on digitized images. At baseline blood pressures, cholesterol levels, and markers of atherosclerosis and inflammation were also measured.

RESULTS

With increasing blood and pulse pressures, retinal arteriolar and venular diameters and the AVR decreased significantly and linearly. Lower arteriolar diameters were associated with increased carotid intima-media thickness. Larger venular diameters were associated with higher carotid plaque score, more aortic calcifications, lower ankle-arm index, higher leukocyte count, higher erythrocyte sedimentation rate, higher total serum cholesterol, lower HDL, higher waist-to-hip ratio, and smoking. A lower AVR was related to increased carotid intima-media thickness, higher carotid plaque score, higher leukocyte count, lower HDL, higher body mass index, higher waist-to-hip ratio, and smoking.

CONCLUSIONS

Because larger venular diameters are associated with atherosclerosis, inflammation, and cholesterol levels, the AVR does not depend only on generalized arteriolar narrowing due to the association between smaller arteriolar diameters and higher blood pressures. These data indicate that retinal venular diameters are variable and may play their own independent role in predicting cardiovascular disorders.

Is medication use associated with the incidence of early age-related maculopathy? Pooled findings from 3 continents

OBJECTIVE

To investigate whether there is an association between the use of medication and the incidence of early age-related maculopathy (ARM).

DESIGN

Pooled data from 3 prospective, population-based cohort studies.

PARTICIPANTS

Subjects without early and late ARM at baseline who participated in the follow-up of the Beaver Dam Eye Study (n = 3012), the Rotterdam Study (n = 3434), and the Blue Mountains Eye Study (n = 2203).

METHODS

Stereoscopic color fundus photographs of all participants were graded according to a standardized protocol. At baseline, current use of prescription and over-the-counter medication was assessed by interview, and the drug name was confirmed at the research centers. Procedures and definitions were similar at both baseline and follow-up across the 3 study sites.

MAIN OUTCOME MEASURES

Incidence of early ARM, defined as the presence at follow-up of either soft distinct drusen with pigmentary changes or soft indistinct or reticular drusen.

RESULTS

In the pooled cohort, 53.3% of participants used at least one of the medications selected for this study. Within a mean period of 5.6 years, a total of 683 subjects developed early ARM. Users of antihypertensive medication in general, and beta-blockers in particular, had a borderline statistically significant increased risk of early ARM (odds ratio [OR] for beta-blockers, 1.3; 95% confidence interval [CI], 1.0-1.6) when adjusted for systolic (or diastolic) blood pressure and other confounders. A protective effect of borderline significance was found among women using hormone replacement therapy (OR, 0.6; 95% CI, 0.4-1.0) and in persons using tricyclic antidepressants (OR, 0.4; 95% CI, 0.2-1.0). In contrast with beta-blockers, the direction and magnitude of the association with hormone replacement therapy and tricyclic antidepressants were inconsistent among the 3 study populations.

CONCLUSIONS

Pooled data from 3 population-based studies showed no strong associations between medication use and the incidence of early ARM. Of borderline significance were a slightly increased risk among users of beta-blockers and a reduced risk among users of hormone replacement therapy and users of tricyclic antidepressants. Although beta-blocker use could be a proxy for systemic hypertension, these findings warrant further investigations, preferably including information on the dosage and duration of drug exposure.

Prevalence of age-related macular degeneration in the United States

OBJECTIVE

To estimate the prevalence and distribution of age-related macular degeneration (AMD) in the United States by age, race/ethnicity, and gender.

METHODS

Summary prevalence estimates of drusen 125 microm or larger, neovascular AMD, and geographic atrophy were prepared separately for black and white persons in 5-year age intervals starting at 40 years. The estimated rates were based on a meta-analysis of recent population-based studies in the United States, Australia, and Europe. These rates were applied to 2000 US Census data and to projected US population figures for 2020 to estimate the number of the US population with drusen and AMD.

RESULTS

The overall prevalence of neovascular AMD and/or geographic atrophy in the US population 40 years and older is estimated to be 1.47% (95% confidence interval, 1.38%-1.55%), with 1.75 million citizens having AMD. The prevalence of AMD increased dramatically with age, with more than 15% of the white women older than 80 years having neovascular AMD and/or geographic atrophy. More than 7 million individuals had drusen measuring 125 microm or larger and were, therefore, at substantial risk of developing AMD. Owing to the rapidly aging population, the number of persons having AMD will increase by 50% to 2.95 million in 2020. Age-related macular degeneration was far more prevalent among white than among black persons.

CONCLUSION

Age-related macular degeneration affects more than 1.75 million individuals in the United States. Owing to the rapid aging of the US population, this number will increase to almost 3 million by 2020.

Cholesterol and age-related macular degeneration: is there a link?

PURPOSE

To examine the relation among serum cholesterol, apolipoprotein E genotype (APOE), and the risk of early and late age-related macular degeneration (AMD).

DESIGN

The Rotterdam Study, a population based prospective cohort study.

METHODS

Serum levels of total and high-density lipoprotein (HDL) cholesterol as well as APOE genotype were determined at baseline. Of 3,944 subjects, 400 were diagnosed with incident early and late AMD after a mean follow-up of 5.2 years.

RESULTS

Serum HDL, but not total, cholesterol was associated with an increased risk of AMD (odds ratio/SD, 1.20; 95% confidence interval; 1.06-1.35). The association remained unchanged after adjustment for APOE genotype. When stratifying for APOE genotype, the association was strongest in persons with the e 4 allele; an inverse association seemed to be present for e 2 carriers.

CONCLUSION

Elevated HDL but not total cholesterol is associated with an increased risk of AMD. Apolipoprotein E genotype does not explain this association but may be an effect modifier.

Epidemiology of age-related maculopathy: a review

Age-related maculopathy (ARM) is a degenerative disease of the retina and the leading cause of incurable blindness and visual impairment in industrialized countries. By definition, ARM is confined to the age-category above 50 years. The aetiology of ARM is still unknown, despite intensive research on many fronts. In this paper, we provide a review of the epidemiology of ARM. The most prominent findings were an exponential increase in frequency with age, a significant familial and genetic component, and a strong association with smoking. Other risk factors that were found less consistently were atherosclerosis, low intake of antioxidant nutrients, and cataract extraction. Future studies, both observational and experimental, will hopefully identify more risk factors that are amenable to prevention.

A Peculiar Autosomal Dominant Macular Dystrophy Caused by an Asparagine Deletion at Codon 169 in the Peripherin/RDS Gene

OBJECTIVE

To describe the clinical and genetic findings in a family with a peculiar autosomal dominant macular dystrophy with peripheral deposits.

METHODS

All family members underwent an ophthalmic examination, and their genomic DNA was screened for mutations in the human retinal degeneration slow (peripherin/RDS) and rhodopsin genes. In selected cases, fluorescein angiography and electrophysiologic testing were performed.

RESULTS

The age at onset of the disease was between the third and fourth decades of life, starting with mild visual acuity loss and periods of metamorphopsia. Clinical signs included subretinal yellowish macular deposits evolving into geographic atrophy and retinal hypopigmentation and hyperpigmentation. Electroretinography demonstrated rod dysfunction, and electro-oculograms were mildly to severely disturbed. All affected members were found to carry a 3-base pair deletion affecting codon 169 of the peripherin/RDS gene. This mutation resulted in an asparagine (Asn) deletion in the peripherin/RDS protein and was not found in 155 control individuals.

CONCLUSION

A deletion of Asn169 in the peripherin/RDS protein causes a peculiar form of autosomal dominant macular dystrophy in a large family from the Netherlands.

CLINICAL RELEVANCE

Characterizing the phenotype and genotype in this family may, in the long term, result in a better understanding of the precise mechanism underlying this retinal degeneration.

Relationship between refraction and prevalent as well as incident age-related maculopathy: the Rotterdam Study

PURPOSE

To study the relationship between baseline spherical equivalents (SphE) of refraction and prevalent as well as incident age-related maculopathy (pARM and iARM, respectively).

METHODS

The study was performed as part of the Rotterdam Study, a population-based, prospective cohort study. The SphE (in diopters), measured with autorefraction and subjective optimization, was recorded in 6209 subjects aged 55 years or more. Aphakic or pseudophakic eyes at baseline were excluded. Stereoscopic transparencies of the macular region were graded according to the International Classification and Grading System. ARM was defined as large soft drusen with pigmentary changes, or indistinct drusen, or atrophic or neovascular age-related macular degeneration (AMD). For the prevalence analyses, ARM was classified into no, p(early)ARM, or pAMD, and in each subject the eye with the most advanced ARM and the corresponding refraction was selected. After a mean 5.2 years of follow-up, 4935 subjects had complete data for these incidence analyses. In each subject, the eye with iARM was selected.

RESULTS

The age- and gender-adjusted odds ratio (OR) of pARM (n = 536) for every diopter of progress toward hyperopia was 1.09 (95% confidence interval [CI]1.04-1.13). For p(early)ARM (n = 440) the OR was 1.09 (1.04-1.14) and for pAMD (n = 96) the OR was 1.09 (1.00-1.19). Baseline refraction was significantly associated with increased risk of iARM (n = 497). For each diopter of progress toward hyperopia the OR was 1.05 (95% CI 1.01-1.10). Additional adjustments for smoking, atherosclerosis, and blood pressure did not alter the relationship.

CONCLUSIONS

These population-based incidence data confirm results from prevalence and case-control studies that there is an association between hyperopia and ARM.

Blood pressure, atherosclerosis, and the incidence of age-related maculopathy: the Rotterdam Study

PURPOSE

To determine whether blood pressure and subclinical atherosclerosis are associated with incident age-related maculopathy (ARM).

METHODS

The study was performed within the Rotterdam Study, a population-based, prospective cohort study in Rotterdam, The Netherlands. A total of 4822 subjects who at baseline were aged 55 years more, were free of ARM, and participated in at least one of two follow-up examinations after a mean of 2 and 6.5 years, were included in the study. At baseline, blood pressure and the presence of atherosclerosis were determined. ARM was assessed according to the International Classification and Grading System and defined as large, soft drusen with pigmentary changes; indistinct drusen; or atrophic or neovascular age-related macular degeneration.

RESULTS

After a mean follow-up of 5.2 years, incident ARM was diagnosed in 417 subjects. Increased systolic blood pressure or pulse pressure was associated with a higher risk of ARM. Adjusted for age, gender, smoking, total and high-density lipoprotein cholesterol, body mass index, and diabetes mellitus, odds ratios (OR) per 10-mm Hg increase were 1.08 (95% confidence interval [CI]: 1.03-1.14) and 1.11 (95% CI: 1.04-1.18), respectively. Moreover, different measures of atherosclerosis were associated with the risk of ARM. An increase in carotid wall thickness (OR per 1 SD, 1.15; 95% CI: 1.03-1.28) increased the risk of ARM. The lowest compared with the highest tertile of ankle-arm index had an OR of 1.32 (95% CI: 1.00-1.75). A weak association was found between aortic calcifications and the risk of ARM.

CONCLUSIONS

Elevated systolic blood or pulse pressure or the presence of atherosclerosis may increase the risk of development of ARM.

Grading of age-related maculopathy for epidemiological studies: is digital imaging as good as 35-mm film?

PURPOSE

To compare stereo digital images with stereo 35-mm color transparencies as to the quality and reliability of grading age-related maculopathy (ARM) in the context of a multicenter European epidemiologic study (the EUREYE Study).

DESIGN

Instrument validation study.

PARTICIPANTS

Ninety-one subjects (137 eyes) with varying degrees of ARM, including no ARM.

METHODS

From both eyes of the participants, 35-mm film and digital stereoscopic fundus images were obtained with two identical Topcon fundus cameras. Two experienced graders classified all signs of ARM according to the International Classification System. Agreement between imaging techniques and between graders was calculated using the weighted kappa statistic.

MAIN OUTCOME MEASURES

Signs of ARM (number, size, and morphologic characteristics of drusen; pigmentary changes; geographic atrophy; and neovascular macular degeneration) as well as an overall staging system of increasing ARM severity.

RESULTS

The weighted kappa value for between-technique agreement ranged from 0.41 for number of drusen <63 microm to 0.79 for drusen type and total area occupied by drusen. The kappa values for atrophic and neovascular end-stage ARM were 0.87 and 0.94, respectively. The between-technique agreement on stages of ARM was approximately 0.76. The agreement between graders was largely the same for both techniques of imaging.

CONCLUSIONS

In the described setting, digital images were as good as 35-mm film for the grading of ARM. Considering the practical advantages of digital imaging, this technique may serve well in epidemiologic studies of ARM.

Is there a direct association between age-related eye diseases and mortality? The Rotterdam Study

PURPOSE

To study mortality in subjects with age-related maculopathy (ARM), cataract, or open-angle glaucoma (OAG) in comparison with those without these disorders.

DESIGN

Population-based prospective cohort study.

PARTICIPANTS

Subjects (n = 6339) aged 55 years and older from the population-based Rotterdam Study for whom complete information on eye disease status was present.

MAIN OUTCOME MEASURES

Vital status continuously monitored from 1990 until January 1, 2000.

METHODS

The diagnosis of ARM was made according to the International Classification System. Cataract, determined on biomicroscopy, was defined as any sign of nuclear or (sub)cortical cataract, or both, in at least one eye with a visual acuity of 20/40 or less. Aphakia and pseudophakia in at least one eye were classified as operated cataract. Definite OAG was defined as a glaucomatous optic neuropathy combined with a glaucomatous visual field defect. Diagnoses were assessed at baseline. Mortality hazard ratios were computed using Cox proportional hazard regression analysis, adjusted for appropriate confounders (age, gender, smoking status, body mass index, cholesterol level, atherosclerosis, hypertension, history of cardiovascular disease, and diabetes mellitus).

RESULTS

The adjusted mortality hazard ratio for subjects with AMD (n = 104) was 0.94 (95% confidence interval [CI], 0.52-1.68), with biomicroscopic cataract (n = 951) was 0.94 (95% CI, 0.74-1.21), with surgical cataract (n = 298) was 1.20 (95% CI, 0.86-1.68), and with definite OAG (n = 44) was 0.39 (95% CI, 0.10-1.55).

CONCLUSIONS

Both ARM and cataract are predictors of shorter survival because they have risk factors that also affect mortality. When adjusted for these factors, ARM, cataract, and OAG were themselves not significantly associated with mortality.

Pseudoxanthoma elasticum: a clinical, histopathological, and molecular update

Pseudoxanthoma elasticum is an autosomally inherited disorder that is associated with the accumulation of mineralized and fragmented elastic fibers in the skin, Bruch's membrane in the retina, and vessel walls. The ophthalmic and dermatologic expression of pseudoxanthoma elasticum and its vascular complications are heterogeneous, with considerable variation in phenotype, progression, and mode of inheritance. Using linkage analysis and mutation detection techniques, mutations in the ABCC6 gene were recently implicated in the etiology of pseudoxanthoma elasticum. ABCC6 encodes the sixth member of the ATP-binding cassette transporter and multidrug resistance protein family (MRP6). In humans, this transmembrane protein is highly expressed in the liver and kidney. Lower expression was found in tissues affected by pseudoxanthoma elasticum, including skin, retina, and vessel walls. So far, the substrates transported by the ABCC6 protein and its physiological role in the etiology of pseudoxanthoma elasticum are not known. A functional transport study of rat MRP6 suggests that small peptides such as the endothelin receptor antagonist BQ123 are transported by MRP6. Similar molecules transported by ABCC6 in humans may be essential for extracellular matrix deposition or turnover of connective tissue at specific sites in the body. One of these sites is Bruch's membrane. This review is an update on etiology of pseudoxanthoma elasticum, including its clinical and genetic features, pathogenesis, and biomolecular basis.

Analysis of the frequent R1141X mutation in the ABCC6 gene in pseudoxanthoma elasticum

PURPOSE

To characterize the ABCC6 R1141X nonsense mutation, which is implicated in more than 25% of a cohort of patients from The Netherlands with pseudoxanthoma elasticum (PXE).

METHODS

A combination of single-strand conformational polymorphism (SSCP), PCR, sequencing, and Southern blot analysis was used to identify mutations in the ABCC6 gene in 62 patients. Haplotypes of 16 patients with the R1141X mutation were determined with eight polymorphic markers spanning the ABCC6 locus. The effect of the R1141X mutation on the expression of ABCC6 was studied in leukocytes and cultured dermal fibroblasts from affected skin in patients heterozygous or homozygous for the R1141X mutation. ABCC6 expression was analyzed by RT-PCR and immunocytochemistry with ABCC6-specific monoclonal antibodies.

RESULTS

The ABCC6 R1141X mutation was found on 19 alleles in 16 patients with PXE and occurred in heterozygous, homozygous, or compound heterozygous form. All R1141X alleles were associated with a common haplotype, covering at least three intragenic ABCC6 markers. None of the patients or healthy control subjects had a similar ABCC6 haplotype. Furthermore, the results showed that the expression of the normal allele in R1141X heterozygotes was predominant, whereas no detectable, or very low, ABCC6 mRNA levels were found in R1141X homozygotes. Immunocytochemical staining of cultured dermal fibroblasts with ABCC6-specific monoclonal antibodies showed no evidence of the presence of a truncated protein in patients with PXE who were homozygous for R1141X.

CONCLUSIONS

A specific founder effect for the R1141X mutation exists in Dutch patients with PXE. The R1141X mutation induces instability of the aberrant mRNA. Functional haploinsufficiency or loss of function of ABCC6 caused by mechanisms, such as nonsense-mediated decay (NMD), may be involved in the PXE phenotype.