Variation in fibrinogen FGG and FGA genes and risk of stroke: the Rotterdam Study

Haplotypes of the fibrinogen gamma and alpha (FGG and FGA) genes are associated with the structure of the fibrin network and may therefore influence the risk of stroke. We investigated the relationship between common variation in these genes with ischemic and haemorrhagic stroke. The study was based on 6,275 participants of the prospective population-based Rotterdam Study who at baseline (1990-1993) were aged 55 years or over, free from stroke, and had successful assessment of at least one FGG or FGA single nucleotide polymorphisms (SNP). Common haplotypes were estimated using seven tagging SNPs across a 30 kb region containing the FGG and FGA genes. Follow-up for incident stroke was complete until January 1, 2005. Associations between constructed haplotypes and risk of stroke were estimated with an age- and sex-adjusted logistic regression model. We observed 668 strokes, of which 393 were ischemic and 62 haemorrhagic, during a median follow-up time of 10.1 years. FGG + FGA haplotype 3 (H3) was associated with an increased risk of ischemic stroke (odds ratio [OR] 1.36, 95% confidence interval [CI] 1.09-1.69) and the risk estimate for hemorrhagic stroke was 0.71 (95% CI 0.46-1.09) compared to the most frequent H1. The FGG and FGA genes were not associated with stroke or its subtypes when analyzed separately. In conclusion, risk of ischemic stroke was higher in FGG + FGA H3 than in H1. The results suggested that an opposite association may exist for haemorrhagic stroke.

Progression of cerebral small vessel disease in relation to risk factors and cognitive consequences: Rotterdam Scan study

BACKGROUND AND PURPOSE

Cerebral white matter lesions and lacunar infarcts are small vessel disease-related lesions, which are associated with cognitive decline and dementia. We aimed to assess the relationship between risk factors, effect modifiers, and progression of these lesions. Furthermore, we studied the cognitive consequences of lesion progression.

METHODS

Six hundred sixty-eight people, aged 60 to 90 years, underwent repeated MRI scanning and neuropsychological testing within 3-year follow-up. We rated incident lacunar infarcts and change in periventricular and subcortical white matter lesion severity with a semiquantitative scale. We assessed the relationships between age, sex, baseline lesion load, risk factors, lesion progression, and change in cognitive function by multivariate regression analyses and additional stratified analyses.

RESULTS

Baseline lesion load, higher age, high blood pressure, and current smoking were independently associated with progression of white matter lesions. Women had more marked progression of subcortical white matter lesions and incident lacunar infarcts compared with men. Carotid atherosclerosis was associated with incident lacunar infarcts. Higher blood pressure did not contribute to lesion progression in people with already severe lesions at baseline nor in the very old. Lesion progression was associated with a paralleled decline in general cognitive function and in particular with a decreased information processing speed.

CONCLUSIONS

Higher age, female sex, cigarette smoking, elevated blood pressure, and baseline lesion load were associated with small vessel disease progression. Age and baseline lesion load influenced the risk relations with blood pressure. Progression of small vessel disease was related to a paralleled decline in cognitive function.

Ankle brachial index combined with Framingham Risk Score to predict cardiovascular events and mortality: a meta-analysis

CONTEXT

Prediction models to identify healthy individuals at high risk of cardiovascular disease have limited accuracy. A low ankle brachial index (ABI) is an indicator of atherosclerosis and has the potential to improve prediction.

OBJECTIVE

To determine if the ABI provides information on the risk of cardiovascular events and mortality independently of the Framingham risk score (FRS) and can improve risk prediction.

DATA SOURCES

Relevant studies were identified. A search of MEDLINE (1950 to February 2008) and EMBASE (1980 to February 2008) was conducted using common text words for the term ankle brachial index combined with text words and Medical Subject Headings to capture prospective cohort designs. Review of reference lists and conference proceedings, and correspondence with experts was conducted to identify additional published and unpublished studies.

STUDY SELECTION

Studies were included if participants were derived from a general population, ABI was measured at baseline, and individuals were followed up to detect total and cardiovascular mortality.

DATA EXTRACTION

Prespecified data on individuals in each selected study were extracted into a combined data set and an individual participant data meta-analysis was conducted on individuals who had no previous history of coronary heart disease.

RESULTS

Sixteen population cohort studies fulfilling the inclusion criteria were included. During 480,325 person-years of follow-up of 24,955 men and 23,339 women, the risk of death by ABI had a reverse J-shaped distribution with a normal (low risk) ABI of 1.11 to 1.40. The 10-year cardiovascular mortality in men with a low ABI (< or = 0.90) was 18.7% (95% confidence interval [CI], 13.3%-24.1%) and with normal ABI (1.11-1.40) was 4.4% (95% CI, 3.2%-5.7%) (hazard ratio [HR], 4.2; 95% CI, 3.3-5.4). Corresponding mortalities in women were 12.6% (95% CI, 6.2%-19.0%) and 4.1% (95% CI, 2.2%-6.1%) (HR, 3.5; 95% CI, 2.4-5.1). The HRs remained elevated after adjusting for FRS (2.9 [95% CI, 2.3-3.7] for men vs 3.0 [95% CI, 2.0-4.4] for women). A low ABI (< or = 0.90) was associated with approximately twice the 10-year total mortality, cardiovascular mortality, and major coronary event rate compared with the overall rate in each FRS category. Inclusion of the ABI in cardiovascular risk stratification using the FRS would result in reclassification of the risk category and modification of treatment recommendations in approximately 19% of men and 36% of women.

CONCLUSION

Measurement of the ABI may improve the accuracy of cardiovascular risk prediction beyond the FRS.

Matrix metalloproteinase 3 haplotypes and plasma amyloid beta levels: the Rotterdam Study

Experimental studies suggest that matrix metalloproteinases (MMPs) are involved in the degradation of amyloid beta (Abeta) protein which plays a key role in the pathogenesis of Alzheimer's disease. Whether MMPs are associated with changes in beta amyloid levels in humans remains unclear. We related common haplotypes within the gene encoding MMP-3 with plasma levels of Abeta(1-40) and Abeta(1-42) in 1621 non-demented participants of the population-based Rotterdam Study. In non-demented persons, plasma Abeta concentration reflect levels of Abeta in the brain. DNA was genotyped for polymorphisms 1187 (5A6A, rs3025058), 2092A>G (rs522616), 9775T>A (rs563096) and 6658T>C (rs3025066) and haplotypes reconstructed (coding from 1187 (5A6A), 2092A>G, 9775T>A and 6658T>C: haplotype 1=5A-A-T-T, haplotype 2=6A-G-T-T, haplotype 3=6A-A-T-T, haplotype 4=6A-A-A-T and haplotype 5=5A-A-T-C). Then the associations of these haplotypes with plasma Abeta(1-40) and Abeta(1-42) levels were assessed using the program Haplo.Stats. Compared with haplotype 1, haplotype 4 was associated with significantly lower levels of plasma Abeta(1-40) (beta=-8.04, 95% CI (-14.79; -1.28), p=0.02) after adjusting for age and sex. Haplotype 2 was associated with significantly higher levels of plasma Abeta(1-42) (beta=3.70, 95% CI (1.75; 5.65), p=0.0002). Our observations suggest that variation in the gene encoding MMP-3 is associated with changes in amyloid beta levels in humans. Factors modulating secretion or activity of MMP-3 may have the potential to influence the amount of Abeta concentration and deposition in the brain.

Haplotypes of the fibrinogen gene and cerebral small vessel disease: the Rotterdam scan study

OBJECTIVE

Fibrinogen levels and fibrinogen clot structure have been implicated in the pathogenesis of vascular disease. We examined fibrinogen levels and variation in fibrinogen genes (fibrinogen gamma (FGG), alpha (FGA) and beta (FGB)), which have been associated with fibrin clot structure and fibrinogen levels, in relation to cerebral small vessel disease (SVD).

METHODS AND RESULTS

This study was performed as part of the Rotterdam Scan Study, a population based study in 1077 elderly patients undergoing cerebral MRI. Plasma fibrinogen levels and haplotypes were determined. We examined the association between fibrinogen levels and haplotype with silent brain infarcts and white matter lesions using logistic regression models. We constructed seven haplotypes (frequency >0.01) that describe the total common variation in the FGG and FGA genes. Haplotype 2 (GATAGTG) was associated with the presence of silent brain infarcts compared with the most frequent haplotype (GGTGGTA) (OR 1.41, 95% CI 1.03 to 1.94). Haplotype 3 (GGCGATA) was associated with periventricular white matter lesions in the highest tertile of the distribution (OR 1.40, 95% CI 1.01 to 1.92). No association was found between plasma fibrinogen levels and SVD.

CONCLUSIONS

Our study provides evidence for an association of common variation in the FGG and FGA genes with cerebral SVD. It is possible that the structure of the fibrin clot rather than plasma fibrinogen levels plays a role in the pathogenesis of cerebral SVD.

Brain tissue volumes in the general elderly population

We investigated how volumes of cerebrospinal fluid (CSF), grey matter (GM) and white matter (WM) varied with age, sex, small vessel disease and cardiovascular risk factors in the Rotterdam Scan Study. Participants (n=490; 60-90 years) were non-demented and 51.0% had hypertension, 4.9% had diabetes mellitus, 17.8% were current smoker and 54.0% were former smoker. We segmented brain MR-images into GM, normal WM, white matter lesion (WML) and CSF. Brain infarcts were rated visually. Volumes were expressed as percentage of intra-cranial volume. With increasing age, volumes of total brain, normal WM and total WM decreased; that of GM remained unchanged; and that of WML increased, in both men and women. Excluding persons with infarcts did not alter these results. Persons with larger load of small vessel disease had smaller brain volume, especially normal WM volume. Diastolic blood pressure, diabetes mellitus and current smoking were also related to smaller brain volume. In the elderly, higher age, small vessel disease and cardiovascular risk factors are associated with smaller brain volume, especially WM volume.

Brain tissue volumes in relation to cognitive function and risk of dementia

We investigated in a population-based cohort study the association of global and lobar brain tissue volumes with specific cognitive domains and risk of dementia. Participants (n=490; 60-90 years) were non-demented at baseline (1995-1996). From baseline brain MRI-scans we obtained global and lobar volumes of CSF, GM, normal WM, white matter lesions and hippocampus. We performed neuropsychological testing at baseline to assess information processing speed, executive function, memory function and global cognitive function. Participants were followed for incident dementia until January 1, 2005. Larger volumes of CSF and WML were associated with worse performance on all neuropsychological tests, and an increased risk of dementia. Smaller WM volume was related to poorer information processing speed and executive function. In contrast, smaller GM volume was associated with worse memory function and increased risk of dementia. When investigating lobar GM volumes, we found that hippocampal volume and temporal GM volume were most strongly associated with risk of dementia, even in persons without objective and subjective cognitive deficits at baseline, followed by frontal and parietal GM volumes.

Cerebral microbleeds: accelerated 3D T2*-weighted GRE MR imaging versus conventional 2D T2*-weighted GRE MR imaging for detection

The purpose of this study was to prospectively compare high-spatial-resolution accelerated three-dimensional (3D) T2*-weighted gradient-recalled-echo (GRE) magnetic resonance (MR) images with conventional two-dimensional (2D) T2*-weighted GRE MR images for the depiction of cerebral microbleeds. After obtaining institutional review board approval and informed consent, 200 elderly participants (age range, 69.7-96.7 years; 108 [54%] women) were imaged at 1.5 T by using both sequences. Presence, number, and location of microbleeds were recorded for both sequences, and differences were tested by using McNemar and signed rank tests. Cerebral microbleeds were detected in significantly more participants on 3D T2*-weighted GRE images (35.5%) than on 2D T2*-weighted GRE images (21.0%; P < .001). Furthermore, in persons with microbleeds visualized on both image sets, significantly more microbleeds (P < .001) were seen on 3D images than on 2D images. For both sequences, the proportion of participants with a microbleed in a lobar (cortical gray and subcortical white matter), deep, or infratentorial location was similar. In conclusion, accelerated 3D T2*-weighted GRE images depict more microbleeds than do conventional 2D T2*-weighted GRE images.

History of depression, depressive symptoms, and medial temporal lobe atrophy and the risk of Alzheimer disease

BACKGROUND

Depression may increase risk for Alzheimer disease (AD), but it is not clear whether this risk is mediated by structural brain changes. We determined whether history of depressive episodes and presence of depressive symptoms were associated with smaller hippocampal and amygdalar volumes and with increased risk for incident AD.

METHODS

Within the Rotterdam Scan Study 503 persons, aged 60-90 years at baseline and without dementia, reported their history of depressive episodes. Depressive symptoms were assessed with the Center for Epidemiologic Studies Depression Scale. Volumetric assessment of the hippocampus and amygdala was performed using three-dimensional MRI. All subjects were followed for an average of 6 years for development of AD, diagnosed according to National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria.

RESULTS

A total of 134 subjects (26.6%) reported a history of depression (88 reported an onset <60 years and 46 a late onset). Multiple linear regression analyses did not reveal a significant association with hippocampal or amygdalar volume for any of the depression parameters. During follow-up, 33 persons developed AD. Cox regression analyses showed that subjects with early onset depression had an increased risk for AD (HR 3.76; 95% CI 1.41 to 10.06), independent of hippocampal and amygdalar volume, whereas this risk was 2.34 (95% CI 0.82 to 6.69) in subjects with a late-onset depression. Depressive symptoms at baseline were not associated with increased risk for AD.

CONCLUSION

History of depression, and particularly an early onset, but not presence of depressive symptoms increased the risk for Alzheimer disease. This risk was not mediated by smaller hippocampal or amygdalar volumes.

Prevalence and risk factors of cerebral microbleeds: the Rotterdam Scan Study

BACKGROUND

Cerebral microbleeds are focal deposits of hemosiderin that can be visualized with MRI. Little is known on their prevalence in the general population and on their etiology. It has been suggested that, in analogy to spontaneous intracranial hemorrhage, the etiology of microbleeds differs according to their location in the brain, with lobar microbleeds being caused by cerebral amyloid angiopathy and deep or infratentorial microbleeds resulting from hypertension and atherosclerosis. We investigated the prevalence of and risk factors for microbleeds in the general population aged 60 years and older.

METHODS

This study is based on 1,062 persons (mean age 69.6 years) from the population-based Rotterdam Scan Study. MRI was performed at 1.5 T and included a sequence optimized to increase the conspicuity of microbleeds. We assessed the relation of APOE genotype, cardiovascular risk factors, and markers of small vessel disease to the presence and location of microbleeds with multiple logistic regression.

RESULTS

Overall prevalence of cerebral microbleeds was high and increased with age from 17.8% in persons aged 60-69 years to 38.3% in those over 80 years. APOE epsilon 4 carriers had significantly more often strictly lobar microbleeds than noncarriers. In contrast, cardiovascular risk factors and presence of lacunar infarcts and white matter lesions were associated with microbleeds in a deep or infratentorial location but not in a lobar location.

CONCLUSION

The prevalence of cerebral microbleeds is high. Our data support the hypothesis that strictly lobar microbleeds are related to cerebral amyloid angiopathy, whereas microbleeds in a deep or infratentorial location result from hypertensive or atherosclerotic microangiopathy.

Total cerebral blood flow and total brain perfusion in the general population: the Rotterdam Scan Study

Reduced cerebral perfusion may contribute to the development of cerebrovascular and neurodegenerative diseases. Little is known on cerebral perfusion in the general population, as most measurement techniques are too invasive for application in large groups of healthy individuals. Total cerebral blood flow (tCBF) can be noninvasively measured by magnetic resonance imaging (MRI) but is highly correlated with brain volume. We calculated total brain perfusion by dividing tCBF by brain volume, and we investigated determinants of total brain perfusion in comparison with tCBF. Secondly, we studied whether persons with a low tCBF or low total brain perfusion have a larger volume of white matter lesions (WML). This study is based on 892 persons aged 60 to 91 years from the Rotterdam Study, a population-based cohort study. We performed two-dimensional (2D) phase-contrast MRI for tCBF measurement. Brain volume and WML volume were quantitatively assessed. Cardiovascular determinants were assessed by interview and physical examination. We assessed associations between cardiovascular determinants and flow measures with linear regression models, adjusted for age and sex. Associations between tCBF or total brain perfusion and WML volume were assessed using general linear models. We found that determinants of tCBF and total brain perfusion differed largely due to the large influence of brain volume on tCBF values. Persons with low total brain perfusion had a significantly larger WML volume compared with those with high total brain perfusion. Prospective studies are required to unravel whether hypoperfusion contributes to WML formation or that tissue damage, manifested by WML, leads to brain hypoperfusion.

Incidence and prognosis of transient neurological attacks

CONTEXT

Transient neurological attacks (TNAs) are attacks with temporary (<24 hours) neurological symptoms. These symptoms can be focal, nonfocal, or a mixture of both. The prognostic significance of TNAs with focal symptoms (better known as transient ischemic attacks [TIAs]) is well understood. Conversely, hardly anything is known about the prognostic significance of TNAs with nonfocal or mixed symptoms.

OBJECTIVE

To study the incidence and prognosis of focal TNAs (or TIAs), nonfocal TNAs, and mixed TNAs.

DESIGN, SETTING, AND PARTICIPANTS

The study population comprised 6062 community-dwelling Rotterdam Study participants who were aged 55 years or older and free from stroke, myocardial infarction, and dementia at baseline (1990-1993). They were followed up for events until January 1, 2005. We analyzed the associations between incident TNAs and subsequent adverse events with age- and sex-adjusted Cox regression models.

MAIN OUTCOME MEASURES

Stroke, ischemic heart disease, or dementia.

RESULTS

During 60 535 person-years, 548 participants developed TNA (282 focal, 228 nonfocal, and 38 mixed). The incidence rate per 1000 person-years was 4.7 (95% confidence interval [CI], 4.1-5.2) for focal TNA, 3.8 (95% CI, 3.3-4.3) for nonfocal TNA, and 0.6 (95% CI, 0.4-0.9) for mixed TNA. Participants with focal TNA were at higher risk of subsequent stroke than participants without TNA (n = 46 vs 540; hazard ratio [HR], 2.14; 95% confidence interval [CI]; 1.57-2.91) but had an equal risk of ischemic heart disease and dementia. Nonfocal TNA patients were at higher risk of stroke (27 vs 540; HR, 1.56; 95% CI, 1.08-2.28) and dementia (30 vs 552; HR, 1.59; 95% CI, 1.11-2.26) than participants without TNA. Mixed TNA patients were at higher risk of stroke (6 vs 540; HR, 2.48; 95% CI, 1.11-5.56), ischemic heart disease (8 vs 779; HR, 2.26; 95% CI, 1.07-4.78), vascular death (8 vs 594; HR, 2.54; 95% CI, 1.31-4.91), and dementia (7 vs 552; HR, 3.46; 95% CI, 1.72-6.98) than participants without TNA.

CONCLUSION

Patients who experience nonfocal TNAs, and especially those with mixed TNAs, have a higher risk of major vascular diseases and dementia than persons without TNA.

Serum calcium and cognitive function in old age

OBJECTIVES

To determine whether serum calcium is associated with cognitive function in elderly individuals in the general population.

DESIGN

Prospective follow-up study of two independent, population-based cohorts.

SETTING

The Rotterdam Study (median follow-up 11 years) and the Leiden 85-plus Study (median follow-up 5 years).

PARTICIPANTS

Three thousand nine hundred ninety-four individuals, mean age 71, from the Rotterdam Study and 560 individuals, all aged 85, from the Leiden 85-plus Study.

MEASUREMENTS

Global cognitive function was assessed in both cohorts using the Mini-Mental State Examination; attention, psychomotor speed, and memory function were assessed in the Leiden 85-plus Study only. Linear regression and linear mixed models were used for statistical analyses.

RESULTS

In the Rotterdam Study, high serum calcium was associated with worse global cognitive function at baseline (P<.05) and a faster rate of decline in cognitive function during follow-up (P=.005) in individuals aged 75 and older but not in younger individuals. In the Leiden 85-plus Study, high serum calcium was associated with worse global cognitive function from age 85 through 90 (P<.001). This observation also held for the specific cognitive domains tested (all P<.01). These results did not change when individuals with serum calcium levels greater than normal (>2.55 mmol/L) were excluded from the analyses.

CONCLUSION

In the general population, high serum calcium levels are associated with faster decline in cognitive function over the age of 75.

Kidney function is related to cerebral small vessel disease

BACKGROUND AND PURPOSE

Poor kidney function, as measured by glomerular filtration rate (GFR), is closely associated with presence of glomerular small vessel disease. Given the hemodynamic similarities between the vascular beds of the kidney and the brain, we hypothesized an association between kidney function and markers of cerebral small vessel disease on MRI. We investigated this association in a population-based study of elderly persons.

METHODS

We measured GFR using the Cockcroft-Gault equation in 484 participants (60 to 90 years of age) from the Rotterdam Scan Study. Using automated MRI-analysis we measured global as well as lobar and deep volumes of gray matter and white matter, and volume of WML. Lacunar infarcts were rated visually. Volumes of deep white matter and WML and presence of lacunar infarcts reflected cerebral small vessel disease. We used linear and logistic regression models to investigate the association between GFR and brain imaging parameters. Analyses were adjusted for age, sex, and additionally for cardiovascular risk factors.

RESULTS

Persons with lower GFR had less deep white matter volume (difference in standardized volume per SD decrease in GFR: -0.15 [95% CI -0.26 to -0.04]), more WML (difference per SD decrease in GFR: 0.14 [95% CI 0.03 to 0.25]), and more often lacunar infarcts, although the latter was not significant. GFR was not associated with gray matter volume or lobar white matter volume. Additional adjustment for cardiovascular risk factors yielded similar results.

CONCLUSIONS

Impaired kidney function is associated with markers of cerebral small vessel disease as assessed on MRI.

Incidental findings on brain MRI in the general population

BACKGROUND

Magnetic resonance imaging (MRI) of the brain is increasingly used both in research and in clinical medicine, and scanner hardware and MRI sequences are continually being improved. These advances are likely to result in the detection of unexpected, asymptomatic brain abnormalities, such as brain tumors, aneurysms, and subclinical vascular pathologic changes. We conducted a study to determine the prevalence of such incidental brain findings in the general population.

METHODS

The subjects were 2000 persons (mean age, 63.3 years; range, 45.7 to 96.7) from the population-based Rotterdam Study in whom high-resolution, structural brain MRI (1.5 T) was performed according to a standardized protocol. Two trained reviewers recorded all brain abnormalities, including asymptomatic brain infarcts. The volume of white-matter lesions was quantified in milliliters with the use of automated postprocessing techniques. Two experienced neuroradiologists reviewed all incidental findings. All diagnoses were based on MRI findings, and additional histologic confirmation was not obtained.

RESULTS

Asymptomatic brain infarcts were present in 145 persons (7.2%). Among findings other than infarcts, cerebral aneurysms (1.8%) and benign primary tumors (1.6%), mainly meningiomas, were the most frequent. The prevalence of asymptomatic brain infarcts and meningiomas increased with age, as did the volume of white-matter lesions, whereas aneurysms showed no age-related increase in prevalence.

CONCLUSIONS

Incidental brain findings on MRI, including subclinical vascular pathologic changes, are common in the general population. The most frequent are brain infarcts, followed by cerebral aneurysms and benign primary tumors. Information on the natural course of these lesions is needed to inform clinical management.

Decreased glomerular filtration rate is a risk factor for hemorrhagic but not for ischemic stroke: the Rotterdam Study

BACKGROUND AND PURPOSE

Persons with early stages of chronic kidney disease, defined by a decreased glomerular filtration rate (GFR), have an increased risk of cardiovascular disease. It is unclear whether decreased GFR is a risk factor for stroke. We assessed the association between GFR and stroke in a prospective population-based cohort study.

METHODS

The study was based on 4937 participants of the Rotterdam Study who at baseline (1990 to 1993) were aged 55 years or over, free from stroke, and had serum creatinine assessment. GFR was estimated with the Cockcroft-Gault equation. Follow-up for incident cerebrovascular disease was complete until January 1, 2005. Data were analyzed with Cox proportional hazards models with adjustment for relevant confounders and results were expressed as hazard ratios with 95% CIs.

RESULTS

During an average follow-up of 10.2 years, 586 strokes (338 ischemic, 44 hemorrhagic, and 204 unspecified strokes) occurred. We found no association between GFR and risk of overall stroke or risk of ischemic stroke. In contrast, with decreasing GFR, the risk of hemorrhagic stroke strongly increased; the age- and sex-adjusted hazard ratio for hemorrhagic stroke was 4.10 (95% CI, 1.25 to 13.42) for lowest versus highest quartile of GFR, and there was a clear and highly significant dose-effect relationship. Adjustment for other vascular risk factors only slightly attenuated this association.

CONCLUSIONS

Decreased GFR is a strong risk factor for hemorrhagic, but not ischemic stroke.

The Rotterdam Study: objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in the Netherlands. The study targets cardiovascular, neurological, ophthalmological and endocrine diseases. As of 2008 about 15,000 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in some 600 research articles and reports (see http://www.epib.nl/rotterdamstudy). This article gives the reasons for the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

Polymorphisms of the renin-angiotensin system are associated with blood pressure, atherosclerosis and cerebral white matter pathology

BACKGROUND

The renin-angiotensin system is involved in the development of hypertension, atherosclerosis and cardiovascular disease. We studied the association between the M235T polymorphism of the angiotensinogen gene (AGT) and the C573T polymorphism of the angiotensin II type 1 receptor (AT1R) and blood pressure, carotid atherosclerosis and cerebrovascular disease.

METHODS

We genotyped over 6000 subjects from the Rotterdam Study and more than 1000 subjects from the Rotterdam Scan Study. We used logistic regression and univariate analyses, adjusting for age and sex with, for AGT, the MM and, for AT1R, the TT genotype as reference.

RESULTS

We found that AGT-235T increased systolic (p for trend = 0.03) and diastolic blood pressure (p for trend = 0.04). The prevalence of carotid plaques was increased 1.25-fold (95% CI 1.02-1.52) in AGT-TT carriers. There was a significant increase in mean volume deep subcortical white matter lesions (WML) for AGT-TT carriers (1.78 ml vs 1.09 ml in the reference group; p = 0.008). A significant interaction was found between AGT and AT1R, further increasing the effect on periventricular and subtotal WML (p for interaction = 0.02). We found a non-significant increased risk of silent brain infarction for AGT-TT carriers and AT1R-CC carriers, but no effect on stroke.

CONCLUSION

We found an association between AGT and blood pressure, atherosclerosis and WML. Also, we found synergistic effects between AGT and AT1R on the development of WML. These findings raise the question of whether the renin-angiotensin system may be a therapeutic target for the prevention of cerebral white matter pathology.

Nonsteroidal anti-inflammatory drugs and the risk of Parkinson disease

BACKGROUND

Several lines of evidence suggest a role of inflammatory processes in Parkinson disease, although it is still unclear whether inflammation is a cause or rather a consequence of neurodegeneration.

METHODS

In a prospective population-based cohort study among 6,512 participants aged >or=55 years, with repeated in-person examination, we evaluated the association between cumulative use of nonsteroidal anti-inflammatory drugs (NSAIDs) and the risk of Parkinson disease. Complete information on filled prescriptions was available from automated pharmacy records. Data were analyzed by means of Cox proportional hazards regression analysis, adjusted for age, sex, smoking habits and coffee consumption.

RESULTS

After an average 9.4 years of follow-up, 88 new cases of Parkinson disease were detected. No association was found between use of NSAIDs and the risk of Parkinson disease (adjusted hazard ratio for any NSAID use, 1.50; 95% confidence interval, 0.95-2.37).

CONCLUSION

Our findings do not support the hypothesis that NSAIDs might decrease the risk of Parkinson disease.

Brain tissue volumes and small vessel disease in relation to the risk of mortality

Brain atrophy and small vessel disease increase the risk of dementia and stroke. In a population-based cohort study (n=490; 60-90 years) we investigated how volumetric measures of atrophy and small vessel disease were related to mortality and whether this was independent of incident dementia or stroke. Brain volume and hippocampal volume were considered as measures of atrophy, whereas white matter lesions (WML) and lacunar infarcts reflected small vessel disease. We first investigated all-cause mortality in the whole cohort. In subsequent analyses we censored persons at incident dementia or incident stroke. Finally, we separately investigated cardiovascular mortality. The average follow-up was 8.4 years, during which 191 persons died. Brain atrophy and hippocampal atrophy, as well as WML increased the risk of death. The risks associated with hippocampal atrophy attenuated when censoring persons at incident dementia, but not at incident stroke. Censoring at either incident dementia or stroke did not change the risk associated with brain atrophy and WML. Moreover, WML were particularly associated with cardiovascular mortality.

Relation between smoking and risk of dementia and Alzheimer disease: The Rotterdam Study

BACKGROUND AND OBJECTIVE

Previous studies relating smoking with the risk of dementia have been inconsistent and limited in their validity by short follow-up times, large intervals between baseline and follow-up assessments, and unspecific determination of dementia diagnosis. We re-assessed after longer follow-up time in the large population-based cohort of the Rotterdam Study whether smoking habits and pack-years of smoking are associated with the risk of dementia, Alzheimer disease (AD), and vascular dementia (VaD).

METHODS

Prospective population-based cohort study in 6,868 participants, 55 years or older and free of dementia at baseline. First, Cox proportional hazard models were used to relate smoking status at baseline with the risks of incident dementia, VaD, and AD, using never smokers as the reference category in all analyses. Then Cox proportional hazard models were used to relate pack-years of smoking with the risks of incident dementia, VaD, and AD. To explore the impact of the APOEepsilon4 allele, sex, and age on the association between smoking status and dementia, we repeated all analyses stratifying, in separate models, by APOEepsilon4 genotype, sex, and median of age.

RESULTS

After a mean follow-up time of 7.1 years, current smoking at baseline was associated with an increased risk of dementia (HR 1.47, 95% CI 1.18 to 1.86) and AD (HR 1.56, 95% CI 1.21 to 2.02). This increase in disease risk was restricted to persons without the APOEepsilon4 allele. There was no association between current smoking and risk of VaD, and there was no association between past smoking and risk of dementia, AD, or VaD.

CONCLUSION

Current smoking increases the risk of dementia. This effect is more pronounced in persons without the APOEepsilon4 allele than APOEepsilon4 carriers.

Plasma folate concentration and cognitive performance: Rotterdam Scan Study

BACKGROUND

Evidence is increasing for beneficial and independent effects of folate on cognitive function, but the underlying biologic mechanism is as yet unknown.

OBJECTIVE

We examined the independent association of plasma folate concentration with cognitive performance and explored the nature of this association by evaluating brain-imaging markers for cerebrovascular disease and brain cell loss.

DESIGN

In the population-based Rotterdam Scan Study, 1033 nondemented participants aged 60-90 y underwent extensive cognitive testing and brain imaging. We cross-sectionally examined the association between plasma folate concentration and cognitive test performance by multivariate linear regression. To evaluate the role of vascular or other mechanisms in this association, we subsequently studied whether plasma folate was related to the presence of white matter lesions and hippocampal and amygdalar volumes.

RESULTS

After multivariate adjustment, the mean change in test score per 1-SD increase in plasma folate was 0.05 (95% CI: 0.01, 0.09) for global cognitive function, 0.08 (95% CI: 0.04, 0.13) for psychomotor speed, and 0.02 (95% CI: -0.04, 0.07) for memory function. Adjustment for homocysteine concentration only slightly diminished these associations. The odds ratio relating a 1-SD increase in plasma folate to the presence compared with the absence of severe white matter lesions was 0.79 (95% CI: 0.66, 0.94), whereas no relation was seen between folate status and hippocampal or amygdalar volume.

CONCLUSIONS

Higher plasma folate concentrations are associated with better global cognitive function and better performance on tests of psychomotor speed, regardless of homocysteine concentration. These associations may be mediated by vascular mechanisms.

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.