Neuropsychological performance in survivors of breast cancer more than 20 years after adjuvant chemotherapy

PURPOSE

Adjuvant chemotherapy for breast cancer can have adverse effects on cognition shortly after administration. Whether chemotherapy has any long-term effects on cognition is largely unknown, yet it becomes increasingly relevant because of the widespread use of chemotherapy for early-stage breast cancer and the improved survival. We investigated whether cyclophosphamide, methotrexate, and fluorouracil (CMF) chemotherapy for breast cancer is associated with worse cognitive performance more than 20 years after treatment.

PATIENTS AND METHODS

This case-cohort study compared the cognitive performance of patients with breast cancer who had a history of adjuvant CMF chemotherapy treatment (six cycles; average time since treatment, 21 years; n = 196) to that of a population-based sample of women never diagnosed with cancer (n = 1,509). Participants were between 50 and 80 years of age. Exclusion criteria were ever use of adjuvant endocrine therapy, secondary malignancy, recurrence, and/or metastasis.

RESULTS

The women exposed to chemotherapy performed significantly worse than the reference group on cognitive tests of immediate (P = .015) and delayed verbal memory (P = .002), processing speed (P < .001), executive functioning (P = .013), and psychomotor speed (P = .001). They experienced fewer symptoms of depression (P < .001), yet had significantly more memory complaints on two of three measures that could not be explained by cognitive test performance.

CONCLUSION

Survivors of breast cancer treated with adjuvant CMF chemotherapy more than 20 years ago perform worse, on average, than random population controls on neuropsychological tests. The pattern of cognitive problems is largely similar to that observed in patients shortly after cessation of chemotherapy. This study suggests that cognitive deficits following breast cancer diagnosis and subsequent CMF chemotherapy can be long lasting.

Automated brain structure segmentation based on atlas registration and appearance models

Accurate automated brain structure segmentation methods facilitate the analysis of large-scale neuroimaging studies. This work describes a novel method for brain structure segmentation in magnetic resonance images that combines information about a structure's location and appearance. The spatial model is implemented by registering multiple atlas images to the target image and creating a spatial probability map. The structure's appearance is modeled by a classifier based on Gaussian scale-space features. These components are combined with a regularization term in a Bayesian framework that is globally optimized using graph cuts. The incorporation of the appearance model enables the method to segment structures with complex intensity distributions and increases its robustness against errors in the spatial model. The method is tested in cross-validation experiments on two datasets acquired with different magnetic resonance sequences, in which the hippocampus and cerebellum were segmented by an expert. Furthermore, the method is compared to two other segmentation techniques that were applied to the same data. Results show that the atlas- and appearance-based method produces accurate results with mean Dice similarity indices of 0.95 for the cerebellum, and 0.87 for the hippocampus. This was comparable to or better than the other methods, whereas the proposed technique is more widely applicable and robust.

Cerebral microbleeds are associated with worse cognitive function: the Rotterdam Scan Study

OBJECTIVE

Cerebral microbleeds are frequently found in the general elderly population and may reflect underlying vascular disease, but their role in cognitive function is unknown.

METHODS

We investigated the association between cerebral microbleeds and performance in multiple cognitive domains in 3,979 persons without dementia (mean age, 60.3 years). Mini-Mental State Examination (MMSE) score and neuropsychological tests were used to assess global cognition and the following cognitive domains: memory, information processing speed, executive function, and motor speed. We used number of microbleeds as continuous variable, and additionally distinguished between persons with no microbleeds, 1 microbleed, 2-4 microbleeds, and ≥5 microbleeds. The association of microbleeds with different cognitive domains was estimated using linear regression models. Additional adjustments were made for vascular risk factors, brain atrophy, and other imaging markers of cerebral small vessel disease. We stratified analyses by location of microbleeds.

RESULTS

A higher number of microbleeds was associated with lower MMSE score and worse performance on tests of information processing speed and motor speed. When analyzed per category, presence of 5 or more microbleeds was associated with worse performance in all cognitive domains, except memory. These associations were most robust in participants with strictly lobar microbleeds, whereas after additional adjustments associations disappeared for deep or infratentorial microbleeds.

CONCLUSIONS

Presence of numerous microbleeds, especially in a strictly lobar location, is associated with worse performance on tests measuring cognitive function, even after adjustments for vascular risk factors and other imaging markers of small vessel disease. These results suggest an independent role for microbleed-associated vasculopathy in cognitive impairment.

Frequent fever episodes and the risk of febrile seizures: the Generation R study

AIM

To examine the association between the number of fever episodes and the risk of febrile seizures.

METHODS

This study was embedded in a population-based prospective cohort study from early foetal life onwards. Information about the occurrence of febrile seizures and fever episodes was collected by questionnaires at the ages of 12, 24 and 36 months. Analyses were based on 3033 subjects. The risk of febrile seizures was compared between children with frequent fever episodes (>2 per year), and children with only 1 or 2 fever episodes per year.

RESULTS

The frequency of fever episodes was not associated with the risk of febrile seizures in the age range of 6-12 months. In the second and third year of life, having more than 2 fever episodes was associated with an increased risk of febrile seizures (odds ratios 2.02 [95% confidence interval 1.13-3.62] and 2.29 [95% confidence interval 1.00-5.24], respectively). In the age range between 6 and 36 months, we observed a significant trend between the frequency of fever episodes (<2, 3-4 or >4 per year) and the risk of febrile seizures (p-value for trend < 0.001). The association between the number of fever episodes and the occurrence of febrile seizures was stronger for children with recurrent febrile seizures.

CONCLUSION

Frequent fever episodes are associated with an increased risk of febrile seizures in the second and third years of life. Further studies are needed to identify the mechanisms underlying this association.

Global and focal brain volume in long-term breast cancer survivors exposed to adjuvant chemotherapy

A limited number of studies have associated adjuvant chemotherapy with structural brain changes. These studies had small sample sizes and were conducted shortly after cessation of chemotherapy. Results of these studies indicate local gray matter volume decrease and an increase in white matter lesions. Up till now, it is unclear if non-CNS chemotherapy is associated with long-term structural brain changes. We compared focal and total brain volume (TBV) of a large set of non-CNS directed chemotherapy-exposed breast cancer survivors, on average 21 years post-treatment, to that of a population-based sample of women without a history of cancer. Structural MRI (1.5T) was performed in 184 chemotherapy-exposed breast cancer patients, mean age 64.0 (SD = 6.5) years, who had been diagnosed with cancer on average 21.1 (SD = 4.4) years before, and 368 age-matched cancer-free reference subjects from a population-based cohort study. Outcome measures were: TBV and total gray and white matter volume, and hippocampal volume. In addition, voxel based morphometry was performed to analyze differences in focal gray matter. The chemotherapy-exposed breast cancer survivors had significantly smaller TBV (-3.5 ml, P = 0.019) and gray matter volume (-2.9 ml, P = 0.003) than the reference subjects. No significant differences were observed in white matter volume, hippocampal volume, or local gray matter volume. This study shows that adjuvant chemotherapy for breast cancer is associated with long-term reductions in TBV and overall gray matter volume in the absence of focal reductions. The observed smaller gray matter volume in chemotherapy-exposed survivors was comparable to the effect of almost 4 years of age on gray matter volume reduction. These volume differences might be associated with the slightly worse cognitive performance that we observed previously in this group of breast cancer survivors.

Genome-wide association study of vascular dementia

BACKGROUND AND PURPOSE

Most studies investigating the genetics of dementia have focused on Alzheimer disease, but little is known about the genetics of vascular dementia. The aim of our study was to identify new loci associated with vascular dementia.

METHODS

We performed a genome-wide association study in the Rotterdam Study, a large prospective population-based cohort study in the Netherlands. We sought to replicate genome-wide significant loci in 2 independent replication samples.

RESULTS

In the discovery analysis of 5700 dementia-free individuals, 67 patients developed incident vascular dementia over a mean follow-up time of 9.3 ± 3.2 years. We showed genome-wide significance for rs12007229, which is located on the X chromosome near the androgen receptor gene (OR, 3.7; 95% CI, 2.3-5.8, per copy of the minor allele; P=1.3 × 10(-8)). This association was further confirmed in 2 independent populations (probability value of combined replication samples=0.024).

CONCLUSIONS

Our study shows a novel genetic locus for vascular dementia on the X chromosome. Further replication of this finding is required.

Automated measurement of local white matter lesion volume

It has been hypothesized that white matter lesions at different locations may have different etiology and clinical consequences. Several approaches for the quantification of local white matter lesion load have been proposed in the literature, most of which rely on a distinction between lesions in a periventricular region close to the ventricles and a subcortical zone further away. In this work we present a novel automated method for local white matter lesion volume quantification in magnetic resonance images. The method segments and measures the white matter lesion volume in 43 regions defined by orientation and distance to the ventricles, which allows a more spatially detailed study of lesion load. The potential of the method was demonstrated by analyzing the effect of blood pressure on the regional white matter lesion volume in 490 elderly subjects taken from a longitudinal population study. The method was also compared to two commonly used techniques to assess the periventricular and subcortical lesion load. The main finding was that high blood pressure was primarily associated with lesion load in the vascular watershed area that forms the border between the periventricular and subcortical regions. It explains the associations found for both the periventricular and subcortical load computed for the same data, and that were reported in the literature. But the proposed method can localize the region of association with greater precision than techniques that distinguish between periventricular and subcortical lesions only.

The Rotterdam Scan Study: design and update up to 2012

Neuroimaging plays an important role in etiologic research on neurological diseases in the elderly. The Rotterdam Scan Study was initiated as part of the ongoing Rotterdam Study with the aim to unravel causes of neurological disease by performing neuroimaging in a population-based longitudinal setting. In 1995 and 1999 random subsets of the Rotterdam Study underwent neuroimaging, whereas from 2005 onwards MRI has been implemented into the core protocol of the Rotterdam Study. In this paper, we discuss the background and rationale of the Rotterdam Scan Study. We also describe the imaging protocol and post-processing techniques, and highlight the main findings to date. Finally, we make recommendations for future research, which will also be the main focus of investigation in the Rotterdam Scan Study.

Serum levels of pregnancy zone protein are elevated in presymptomatic Alzheimer's disease

We have sought for disease-related proteins that could predict the onset of Alzheimer's disease (AD) in a study population derived from the Rotterdam Scan Study, a population-based prospective cohort study designed to investigate the etiology and natural history of age-related brain changes in the elderly. The serum proteome of 43 persons who developed AD, after an average of 4.2 years (±2.6 years SD) after blood sampling, and 43 gender- and age-matched controls who remained dementia-free during follow-up was investigated by liquid chromatography mass spectrometry. We identified 61 differentially expressed peptides between presymptomatic AD and controls, 9 of which were derived from pregnancy zone protein (PZP). Quantitative measurements using a multiple reaction monitoring assay showed a significant increase in concentration of PZP in presymptomatic AD (34.3 ± 20.6 mg/L) compared with controls (23.6 ± 13.6 mg/L) (p = 0.006). The difference in PZP was significant in women. Immunohistochemical validation of the findings on brain tissue sections showed strong PZP expression in senile plaques and in microglial and glial cells in AD with only low expression in some scattered glial cells in controls.

Serum lipid levels and the risk of intracerebral hemorrhage: the Rotterdam Study

OBJECTIVE

Low serum total cholesterol levels are associated with an increased risk of symptomatic intracerebral hemorrhage and with presence of asymptomatic cerebral microbleeds. The relative contribution of lipid fractions to these associations is unclear and requires investigation. We determined whether serum HDL-cholesterol, LDL-cholesterol, and triglycerides are associated with risk of intracerebral hemorrhage and presence of cerebral microbleeds.

METHODS AND RESULTS

Nine thousand sixty-eight stroke-free community-dwelling persons aged ≥55 were followed from baseline (1990-2001) up to January 1, 2009, of whom 85 suffered from intracerebral hemorrhage during follow-up. Brain MRI was carried out in 789 healthy participants, of whom 162 had cerebral microbleeds. Triglycerides were strongly and inversely associated with intracerebral hemorrhage, independently of HDL-cholesterol, LDL-cholesterol, and potential confounders [hazard ratio for highest versus lowest quartile: 0.20 (0.06-0.69)]. Triglycerides were also associated with deep or infratentorial microbleeds [odds ratio for highest versus lowest quartile: 0.37 (0.14-0.96)], but not with strictly lobar microbleeds. No associations were found for HDL-cholesterol or LDL-cholesterol.

CONCLUSIONS

Low serum triglyceride levels were associated with an increased risk of intracerebral hemorrhage and with the presence of deep or infratentorial cerebral microbleeds. This provides novel insights into the role of lipid fractions, particularly triglycerides, in the etiology of intracerebral hemorrhage.

Replication study of chr17q25 with cerebral white matter lesion volume

BACKGROUND AND PURPOSE

Recently, the first genomewide association study on cerebral white matter lesion burden identified chr17q25 to be significantly associated with white matter lesions. We report on the first independent replication study of this genetic association.

METHODS

In a population-based cohort study, we investigated the association between the 6 genomewide significant single nucleotide polymorphisms at that locus and cerebral white matter lesion volume on MRI, measured quantitatively, adjusted for age, sex, and intracranial volume. Adjustments for ApoE4 carriership and cardiovascular risk factors were evaluated separately. Finally, we performed a meta-analysis of all published data for the single most significant single nucleotide polymorphism, rs3744028.

RESULTS

The risk alleles of all the 6 single nucleotide polymorphisms were significantly associated with white matter lesion volume with P=1.1*10(-3) for rs3744028, adjusted for age, sex, and intracranial volume. Additional adjustments only had minor influence on these associations. A meta-analysis with all published data for rs3744028 resulted in a probability value of 5.3*10(-17).

CONCLUSIONS

This study further establishes chr17q25 as a novel genetic locus for WML volume.

Genome-wide association studies of cerebral white matter lesion burden: the CHARGE consortium

OBJECTIVE

White matter hyperintensities (WMHs) detectable by magnetic resonance imaging are part of the spectrum of vascular injury associated with aging of the brain and are thought to reflect ischemic damage to the small deep cerebral vessels. WMHs are associated with an increased risk of cognitive and motor dysfunction, dementia, depression, and stroke. Despite a significant heritability, few genetic loci influencing WMH burden have been identified.

METHODS

We performed a meta-analysis of genome-wide association studies (GWASs) for WMH burden in 9,361 stroke-free individuals of European descent from 7 community-based cohorts. Significant findings were tested for replication in 3,024 individuals from 2 additional cohorts.

RESULTS

We identified 6 novel risk-associated single nucleotide polymorphisms (SNPs) in 1 locus on chromosome 17q25 encompassing 6 known genes including WBP2, TRIM65, TRIM47, MRPL38, FBF1, and ACOX1. The most significant association was for rs3744028 (p(discovery) = 4.0 × 10(-9) ; p(replication) = 1.3 × 10(-7) ; p(combined) = 4.0 × 10(-15) ). Other SNPs in this region also reaching genome-wide significance were rs9894383 (p = 5.3 × 10(-9) ), rs11869977 (p = 5.7 × 10(-9) ), rs936393 (p = 6.8 × 10(-9) ), rs3744017 (p = 7.3 × 10(-9) ), and rs1055129 (p = 4.1 × 10(-8) ). Variant alleles at these loci conferred a small increase in WMH burden (4-8% of the overall mean WMH burden in the sample).

INTERPRETATION

This large GWAS of WMH burden in community-based cohorts of individuals of European descent identifies a novel locus on chromosome 17. Further characterization of this locus may provide novel insights into the pathogenesis of cerebral WMH.

Large-scale candidate gene analysis in whites and African Americans identifies IL6R polymorphism in relation to atrial fibrillation: the National Heart, Lung, and Blood Institute's Candidate Gene Association Resource (CARe) project

BACKGROUND

The genetic background of atrial fibrillation (AF) in whites and African Americans is largely unknown. Genes in cardiovascular pathways have not been systematically investigated.

METHODS AND RESULTS

We examined a panel of approximately 50,000 common single-nucleotide polymorphisms (SNPs) in 2095 cardiovascular candidate genes and AF in 3 cohorts with participants of European (n=18,524; 2260 cases) or African American descent (n=3662; 263 cases) in the National Heart, Lung, and Blood Institute's Candidate Gene Association Resource. Results in whites were followed up in the German Competence Network for AF (n=906, 468 cases). The top result was assessed in relation to incident ischemic stroke in the Cohorts for Heart and Aging Research in Genomic Epidemiology Stroke Consortium (n=19,602 whites, 1544 incident strokes). SNP rs4845625 in the IL6R gene was associated with AF (relative risk [RR] C allele, 0.90; 95% confidence interval [CI], 0.85-0.95; P=0.0005) in whites but did not reach statistical significance in African Americans (RR, 0.86; 95% CI, 0.72-1.03; P=0.09). The results were comparable in the German AF Network replication, (RR, 0.71; 95% CI, 0.57-0.89; P=0.003). No association between rs4845625 and stroke was observed in whites. The known chromosome 4 locus near PITX2 in whites also was associated with AF in African Americans (rs4611994; hazard ratio, 1.40; 95% CI, 1.16-1.69; P=0.0005).

CONCLUSIONS

In a community-based cohort meta-analysis, we identified genetic association in IL6R with AF in whites. Additionally, we demonstrated that the chromosome 4 locus known from recent genome-wide association studies in whites is associated with AF in African Americans.

A study of the bidirectional association between hippocampal volume on magnetic resonance imaging and depression in the elderly

BACKGROUND

Hippocampal volume loss on magnetic resonance imaging (MRI) has been reported in patients with depression. It is uncertain whether a small hippocampus renders a person vulnerable to develop depression or whether it is a consequence of depression. In this study, we addressed whether smaller baseline MRI hippocampal volumes increase the risk of incident depression. We also examined whether depressive symptoms at baseline were associated with decline in hippocampal volume during follow-up.

METHODS

Data were obtained in a prospective population-based study over a 10-year period. A sample of 514 nondemented persons aged 60 to 90 years underwent baseline measurements in 1995-1996 including three-dimensional MRI scans for assessment of hippocampal volumes and depressive symptoms (measured with Center for Epidemiologic Studies Depression Scale). Follow-up MRIs were made in 1999-2000 and in 2006. Incident depression was identified through standardized psychiatric examinations and continuous monitoring of medical and pharmaceutical records.

RESULTS

During a mean follow-up of 6.8 years per person (range .07-10.01 years), 135 of the 514 persons developed a clinically relevant episode of incident depressive symptoms. There was no association between baseline hippocampal volumes and incident depression (hazard ratio per SD decrease of average hippocampal volume .98 [.81-1.19], p = .84). A baseline Center for Epidemiologic Studies Depression Scale score of 16 or higher predicted a faster rate of decline in hippocampal volume. Also, incident depression was accompanied by a faster decline in left hippocampal volume.

CONCLUSIONS

This study provides no evidence that a small hippocampal volume precedes the development of late-life depression. Depression, however, may lead to a faster rate of hippocampal volume decline.

Burden of atherosclerosis improves the prediction of coronary heart disease but not cerebrovascular events: the Rotterdam Study

AIMS

Since atherosclerosis is a systemic process, risk prediction would benefit from targeting multiple components of cardiovascular disease simultaneously. To this end, it is useful to examine the predictive value of non-invasive measures of atherosclerosis in various vascular beds for both coronary heart disease (CHD) and cerebrovascular disease.

METHODS AND RESULTS

Between September 2003 and February 2006, 2153 asymptomatic participants (69.6±6.6 years) from the Rotterdam Study underwent a multi-detector computed tomography scan. During a median follow-up of 3.5 years, 58 CHD events (myocardial infarction and CHD death) and 52 cerebrovascular events (TIA and stroke) occurred. Participants were classified into low (<5%), intermediate (5-10%), and high (>10%) 5-year risk categories based on a refitted Framingham risk model. The model was extended by coronary, aortic arch, or carotid calcium and reclassification percentages were calculated. For the outcome CHD, the C-statistic improved from 0.693 for the Framingham refitted model to 0.743, 0.740, and 0.749 by addition of coronary, aortic arch, and carotid calcium, respectively. Reclassification was most substantial in the intermediate risk group where addition of coronary calcium reclassified 56% of persons [net reclassification improvement (NRI): 15%; P<0.01)]. Adding aortic arch calcium led to a reclassification of 32% of persons (NRI: 8%; P=0.01) and adding carotid calcium reclassified 51% (NRI: 9%; P=0.02). In contrast, calcification in any of the three vascular beds did not improve cerebrovascular risk prediction.

CONCLUSION

Coronary, aortic arch, and carotid artery calcification significantly improved risk prediction of CHD but not of cerebrovascular events.

Common variants at ABCA7, MS4A6A/MS4A4E, EPHA1, CD33 and CD2AP are associated with Alzheimer's disease

We sought to identify new susceptibility loci for Alzheimer's disease through a staged association study (GERAD+) and by testing suggestive loci reported by the Alzheimer's Disease Genetic Consortium (ADGC) in a companion paper. We undertook a combined analysis of four genome-wide association datasets (stage 1) and identified ten newly associated variants with P ≤ 1 × 10(-5). We tested these variants for association in an independent sample (stage 2). Three SNPs at two loci replicated and showed evidence for association in a further sample (stage 3). Meta-analyses of all data provided compelling evidence that ABCA7 (rs3764650, meta P = 4.5 × 10(-17); including ADGC data, meta P = 5.0 × 10(-21)) and the MS4A gene cluster (rs610932, meta P = 1.8 × 10(-14); including ADGC data, meta P = 1.2 × 10(-16)) are new Alzheimer's disease susceptibility loci. We also found independent evidence for association for three loci reported by the ADGC, which, when combined, showed genome-wide significance: CD2AP (GERAD+, P = 8.0 × 10(-4); including ADGC data, meta P = 8.6 × 10(-9)), CD33 (GERAD+, P = 2.2 × 10(-4); including ADGC data, meta P = 1.6 × 10(-9)) and EPHA1 (GERAD+, P = 3.4 × 10(-4); including ADGC data, meta P = 6.0 × 10(-10)).

The world of dementia beyond 2020

Counterpoised against dire projections of the tripling of the prevalence of dementia over the next 40 years are major developments in diagnostic biomarkers, neuroimaging, the molecular biology of Alzheimer's disease (AD), epidemiology of risk and protective factors, and drug treatments-mainly targeting the amyloid pathway, tau protein, and immunotherapy-that may have the potential to modify the progression of AD. Drug combinations and presymptomatic treatments are also being investigated. Previous trials of dementia-modifying drugs have not shown benefit, and even if current Phase III trials prove successful, these drugs will not eradicate other dementias, could (if not curative) increase dementia duration and prevalence, and are unlikely to come onto the market before 2020. In the meantime, delaying the onset of dementia by even 2 years would have significant economic and societal effects. This article provides an overview of current achievements and potentials of basic and clinical research that might affect the development of dementia prevalence and care within the near future.

Plasma clusterin and the risk of Alzheimer disease

CONTEXT

Variants in the clusterin gene are associated with the risk of Alzheimer disease (AD) and clusterin levels have been found to be increased in brain and cerebrospinal fluid of patients with AD. Plasma clusterin was reported to be associated with brain atrophy, baseline disease severity, and rapid clinical progression in patients with AD.

OBJECTIVE

To evaluate the potential of plasma clusterin as a biomarker of the presence, severity, and risk of AD.

DESIGN, SETTING, AND PARTICIPANTS

A case-cohort study nested within the Rotterdam Study, a prospective population-based cohort study conducted in Rotterdam, The Netherlands. Plasma levels of clusterin were measured at baseline (1997-1999) in 60 individuals with prevalent AD, a random subcohort of 926 participants, and an additional 156 participants diagnosed with AD during follow-up until January 1, 2007 (mean [SD], 7.2 [2.3] years).

MAIN OUTCOME MEASURES

Prevalent AD, severity of AD measured by the Mini-Mental State Examination (MMSE) score, and the risk of developing AD during follow-up.

RESULTS

The likelihood of prevalent AD increased with increasing plasma levels of clusterin (odds ratio [OR] per SD increase of plasma clusterin level, 1.63; 95% confidence interval [CI], 1.21-2.20; adjusted for age, sex, education level, apolipoprotein E status, diabetes, smoking, coronary heart disease, and hypertension). Among patients with AD, higher clusterin levels were associated with more severe disease (adjusted difference in MMSE score per SD increase in clusterin levels, -1.36; 95% CI, -2.70 to -0.02; P = .047). Plasma clusterin levels were not related to the risk of incident AD during total follow-up (adjusted HR, 1.00; 95% CI, 0.85-1.17; P for trend = .77) or within 3 years of baseline (adjusted HR, 1.09; 95% CI, 0.84-1.42; P for trend = .65).

CONCLUSION

Plasma clusterin levels were significantly associated with baseline prevalence and severity of AD, but not with incidence of AD.

Retinal vascular caliber and risk of dementia: the Rotterdam study

BACKGROUND

Retinal vessels provide a unique opportunity to study both systemic and cerebrovascular disease. Smaller retinal arteriolar calibers are strongly related to hypertension, whereas larger retinal venular calibers are more related to inflammation, cerebral hypoperfusion, and cerebrovascular disease. Whether retinal vessel calibers are related to dementia remains unclear.

METHODS

We investigated whether retinal arteriolar and venular calibers are associated with risk of dementia, and its subtypes Alzheimer disease (AD) and vascular dementia, in the prospective population-based Rotterdam Study. Digitized retinal images were available in 5,553 participants aged 55 years or over and dementia-free at baseline (1990-1993). Participants were re-examined in 1993-1994, 1997-1999, and 2002-2004 and were continuously monitored for development of dementia.

RESULTS

During a mean follow-up of 11.6 years, 655 participants developed dementia. AD was diagnosed in 519 and vascular dementia in 73 participants. Larger venular calibers were associated with an increased risk of dementia, in particular vascular dementia (age- and sex-adjusted hazard ratio per SD increase: 1.31; 95% confidence interval 1.06-1.64), but not AD. The association remained significant after adjustment for stroke and cardiovascular risk factors. Smaller arteriolar calibers were also associated with an increased risk of vascular dementia, yet only when adjusted for venular calibers.

CONCLUSIONS

Retinal venular widening is associated with an increased risk of vascular dementia. Our findings are in line with previous observations in stroke and cerebral small-vessel disease and suggest that the association between larger retinal venular calibers and dementia may reflect cerebral hypoperfusion and subsequent ischemia.

Genetic risk factors for cerebral small-vessel disease in hypertensive patients from a genetically isolated population

BACKGROUND

Asymptomatic cerebral lesions on MRI such as white matter lesions (WML), lacunes and microbleeds are commonly seen in older people. We examined the role of a series of candidate genes involved in blood pressure regulation and amyloid metabolism.

MATERIALS AND METHODS

The study was embedded in a family-based cohort sampled from a Dutch genetically isolated population. We selected individuals between 55 and 75 years of age with hypertension (N=129). Volumes of WML and presence of lacunes and microbleeds were assessed with MRI. We studied three genes involved in blood pressure regulation (angiotensin, angiotensin II type 1 receptor, α-adducin) and two genes involved in the amyloid pathway (apolipoprotein E (APOE) and sortilin-related receptor gene (SORL1)).

RESULTS

All participants had WML (median volume, 3.1 ml; interquartile range, 1.5-6.5 ml); lacunar infarcts were present in 15.5% and microbleeds in 23.3%. Homozygosity for the APOE ε4 allele was associated with lacunes (OR, 4.8; 95% CI, 1.2 to 19.3). Individuals carrying two copies of the variant allele of four single nucleotide polymorphism (SNPs) located at the 3'-end of SORL1 (rs1699102, rs3824968, rs2282649, rs1010159) had significantly more often microbleeds (highest OR, 6.87; 95% CI, 1.78 to 26.44).

CONCLUSION

The association of SORL1 with microbleeds suggests that the amyloid cascade is involved in the aetiology of microbleeds in populations with hypertension.

Insulin metabolism and the risk of Alzheimer disease: the Rotterdam Study

OBJECTIVE

Diabetes mellitus has been associated with an increased risk of Alzheimer disease (AD), but how it exerts its effect remains controversial. Possible pathophysiologic mechanisms are glucose toxicity and a direct effect of insulin on amyloid metabolism. Most studies had short follow-up, and longer-term effects of diabetes on AD risk are unknown. We investigated whether fasting glucose and insulin levels and insulin resistance are associated with the risk of AD and whether this risk is constant over time.

METHODS

The study was based on 3,139 participants of the Rotterdam Study, a population-based cohort study. All subjects were free from dementia, did not have a history of diabetes, and had fasting levels of glucose and insulin measured at baseline. Insulin resistance was estimated with the homeostasis model assessment. We investigated how fasting glucose, insulin, and insulin resistance are related to the risk of AD in 3 different strata according to time-to-event, using Cox proportional hazards models.

RESULTS

During follow-up, 211 participants developed AD, 71 of them within 3 years of baseline. Levels of insulin and insulin resistance were associated with a higher risk of AD within 3 years of baseline. After 3 years, the risk was no longer increased. Glucose was not associated with a higher risk of AD. There was no interaction of APOE ε4 carriership and insulin metabolism on the risk of AD.

CONCLUSIONS

Our findings suggest that insulin metabolism influences the clinical manifestation of AD only within 3 years.