The Rotterdam Study: 2010 objectives and design update.

Abstract

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in close to a 1,000 research articles and reports (see www.epib.nl/rotterdamstudy). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

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CHRONIC DISEASES
The Rotterdam Study: 2010 objectives and design update
Albert Hofman Æ Æ Monique M. B. Breteler Æ Æ Cornelia M. van Duijn Æ Æ
Harry L. A. Janssen Æ Æ Gabriel P. Krestin Æ Æ Ernst J. Kuipers Æ Æ
Bruno H. Ch. Stricker Æ Æ Henning Tiemeier Æ Æ Andre ´ G. Uitterlinden Æ Æ
Johannes R. Vingerling Æ Æ Jacqueline C. M. Witteman
Received: 30 July 2009/Accepted: 19 August 2009/Published online: 2 September 2009
? The Author(s) 2009. This article is published with open access at Springerlink.com
Abstract
study ongoing since 1990 in the city of Rotterdam in The
Netherlands. The study targets cardiovascular, endocrine,
hepatic, neurological, ophthalmic, psychiatric and respira-
tory diseases. As of 2008, 14,926 subjects aged 45 years or
over comprise the Rotterdam Study cohort. The findings of
the Rotterdam Study have been presented in close to a 1,000
research articles and reports (see www.epib.nl/rotterdam
study). This article gives the rationale of the study and its
design. It also presents a summary of the major findings and
an update of the objectives and methods.
The Rotterdam Study is a prospective cohort
Keywords
Cohort study ? Endocrine diseases ? Epidemiologic
methods ? Genetic epidemiology ? Liver diseases ?
Neurological diseases ? Ophthalmic diseases ?
Pharmacoepidemiology ? Psychiatric diseases ?
Respiratory diseases
Biomarkers ? Cardiovascular diseases ?
Introduction
The Rotterdam Study was designed in the mid-1980s as a
response to the demographic changes that were leading to
an increase of the proportion of elderly people in most
populations [1]. It was clear that this would produce a
strong rise in elderly people living with diseases, as most
diseases cluster at the end of life, and that to discover the
causes of diseases in the elderly one would have to study
risk factors of those diseases [2]. A major approach to
finding causes is the prospective follow-up study, which
has proven quite effective in finding causes of heart disease
and cancer.
The design of the Rotterdam Study
The basic design of the study is straight-forward: a pro-
spective cohort study among, initially, 7,983 persons living
in the well-defined Ommoord district in the city of Rot-
terdam in The Netherlands (78% of 10,215 invitees). They
were all 55 years of age or over and the oldest participant
at the start was 106 years [3, 4]. The study started with a
pilot phase in the second half of 1989. From January 1990
onwards participants were recruited for the Rotterdam
Study. Figure 1 gives a diagram of the various cycles in the
study.
In 1999, 3,011 participants (out of 4,472 invitees) who
had become 55 years of age or moved into the study dis-
trict since the start of the study were added to the cohort.
In 2006 a further extension of the cohort was initiated in
which 3,932 subjects were included, aged 45–54 years, out
of 6,057 invited, living in the Ommoord district. By the end
of 2008, the Rotterdam Study therefore comprised 14,926
subjects aged 45 years or over. The overall response figure
A. Hofman (&) ? M. M. B. Breteler ? C. M. van Duijn ?
B. H. Ch. Stricker ? H. Tiemeier ? A. G. Uitterlinden ?
J. R. Vingerling ? J. C. M. Witteman
Department of Epidemiology, Erasmus Medical Center,
PO Box 2040, 3000 CA Rotterdam, The Netherlands
e-mail: a.hofman@erasmusmc.nl
H. L. A. Janssen ? E. J. Kuipers ? B. H. Ch. Stricker ?
A. G. Uitterlinden
Department of Internal Medicine, Erasmus Medical Center,
Rotterdam, The Netherlands
G. P. Krestin
Department of Radiology, Erasmus Medical Center,
Rotterdam, The Netherlands
J. R. Vingerling
Department of Ophthalmology, Erasmus Medical Center,
Rotterdam, The Netherlands
123
Eur J Epidemiol (2009) 24:553–572
DOI 10.1007/s10654-009-9386-z

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for all three cycles at baseline was 72.0% (14,926 of
20,744).
The participants were all examined in some detail at
baseline. They were interviewed at home (2 h) and then
had an extensive set of examinations (a total of 5 h) in a
specially built research facility in the centre of their dis-
trict. These examinations focussed on possible causes of
invalidating diseases in the elderly in a clinically state-of-
the-art manner, as far as the circumstances allowed. The
emphasis was put on imaging (of heart, blood vessels, eyes,
skeleton and later brain) and on collecting bodily fluids that
enabled further in-depth molecular and genetic analyses.
These examinations were repeated every 3–4 years in
characteristics that could change over time. And so we had
examination cycles from 1990 to 1993, from 1993 to 1995,
from 1997 to 1999, from 2000 to 2001, from 2002 to 2004,
from 2004 to 2005 and from 2006 to 2008 (Fig. 1). In 2009
a new examination cycle started (RS-I-5).
The participants in the Rotterdam Study are followed for
a variety of diseases that are frequent in the elderly (and
many are also in the not so elderly): coronary heart disease,
heart failure and stroke, Parkinson disease, Alzheimer
disease and other dementias, depression and anxiety dis-
orders, macular degeneration and glaucoma, respiratory
diseases, liver diseases, diabetes mellitus and osteoporosis.
The Rotterdam Study has been approved by the insti-
tutional review board (Medical Ethics Committee) of the
Erasmus Medical Center and by the review board of
The Netherlands Ministry of Health, Welfare and Sports.
The approval has been renewed every 5 years, as well as
with the introduction of major new elements in the study
(e.g., MRI investigations).
In the remainder of this article the objectives and major
findings will be presented with an update of the methods
for cardiovascular diseases, endocrine diseases, liver dis-
eases, neurological diseases, ophthalmic diseases, psychi-
atric diseases, respiratory diseases, as well as for genetic
and biomarker studies and for pharmaco-epidemiologic
studies. For relevant recent EJE references see [5–27].
Cardiovascular diseases
Objectives
Research on the epidemiology of cardiovascular diseases
focuses on three primary areas of interest: studies on risk
factors for atherosclerosis and coronary heart disease,
studies on the detection of subjects at high risk of coronary
heart disease, and studies on cardiovascular conditions at
older age.
Three groups of putative risk factors for atherosclerosis
and coronary heart disease are included. The first are endo-
crine factors, including diabetes, insulin and insulin-like
growth factor I, estrogens and androgens, and thyroid gland
and adrenal gland hormones. The second group contains
factorsinvolvedinhemostasis,inflammationandendothelial
function. The third group, and currently a major focus,
Fig. 1 Diagram of examination cycles of the Rotterdam Study (RS).
RS-I-1 refers to the baseline examination of the original cohort (pilot
phase 07/1989-12/1989; cohort recruitment 01/1990-09/1993). RS-I-2,
RS-I-3 and RS-I-4 refer to re-examination of the original cohort
members. RS-II-1 refers to the extension of the cohort with persons in
the study district that became 55 years since the start of the study or
those of 55 years or over that migrated to the study district. RS-II-2
refers to the re-examination of the extension cohort. RS-III-1 refers to
the baseline examination of all persons aged 45 years and over living
in the study district that had not been examined (i.e., mainly
comprising those aged 45–55 years)
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covers genetic factors in these areas in relation to risk of
atherosclerosis and heart disease.
The ability of classical cardiovascular risk factors to
identify subjects at high risk of coronary heart disease is
limited. Risk stratification may be improved when based on
the presence of atherosclerosis. To this end, repeated
measurements of non-coronary atherosclerosis and mea-
surements of coronary, carotid and aortic arch calcification
have been included in the study.
Another line of research focuses on cardiovascular dis-
eases in the elderly that are in large part the consequence of
ischemic heart disease, like heart failure and atrial fibril-
lation. An important topic in this area is the early diagnosis
of heart failure using echocardiographic assessment of
asymptomatic systolic and diastolic dysfunction of the left
ventricle. Atrial fibrillation is another major chronic con-
dition frequent at older age. Examination of the determi-
nants and prognosis of atrial fibrillation is part of this
research line.
Major findings
Recent findings include the association between structural
and diastolic echocardiographic parameters and all-cause
mortality in individuals initially free of myocardial infarc-
tion, heart failure, atrial fibrillation, or atrial flutter [28]. The
study found that gender differences in atherosclerosis are
larger in coronary vessels than in carotid, aortic, or lower
extremity vessels [29]. The insertion/deletion polymor-
phism of the angiotensin converting enzyme gene was
found to be associated with increased mean changes of
systolic blood pressure and pulse pressure [30].
We studied the validity of the Framingham Points
Scores in our population and found that they perform
reasonably well in elderly women, but need recalibration in
elderly men [31]. The study showed that C-reactive protein
(CRP) levels are associated with the extent and progression
of ankle-brachial-index and carotid plaques and, albeit less
pronounced, with aortic calcification and intima-media
thickness [32].
The study enabled accurate assessment of the incidence
and lifetime risk of heart failure and atrial fibrillation in an
elderly population [33, 34]. It was shown that inflammation
is associated with heart failure [35]. Subclinical athero-
sclerosis, cigarette smoking and high-normal thyroid
function were identified as new risk factors of atrial
fibrillation [36–38].
The study showed that serum CRP is associated with the
risk of type 2 diabetes independent of obesity. Moreover,
genetic variants in the CRP gene were associated with the
risk of diabetes [39]. The study showed that subjects with
higher levels of serum uric acid have an increased risk of
developing type 2 diabetes [40]. In collaborative work with
the Framingham Heart Study, we identified 3 genetic loci
associated with uric acid concentration and gout [41]. In a
large collaborative consortium, the CHARGE consortium,
we identified a significant association between chronic
kidney disease and the UMOD gene which encodes Tamm-
Horsfall protein [42]. In the same consortium, we found
four genes for systolic blood pressure, six for diastolic
blood pressure and one for hypertension, as well as 1
genetic locus associated with variation in left ventricular
diastolic dimensions and five loci associated with aortic
root size [43, 44].
Methods update
Repeated measures of non-coronary atherosclerosis include
carotid intima-media thickness and plaques by ultrasound
and the ankle-arm index [45]. In previous examinations,
electron-beam CT and, more recently, multi-detector CT
were used to accurately quantify calcification in the coro-
nary, aortic arch and carotid arteries [46]. Measurement of
plaque vulnerability with high-resolution MRI of the car-
otid arteries started in October 2007 and will be continued.
Other outcome measures include electrocardiography,
echocardiography and abdominal aortic diameter measured
by ultrasound [28]. In addition to repeated measures of
structural and functional parameters of the left ventricle
and atrium, measurements of structure and function of the
right side of the heart will be performed.
Determinants are assessed by physical examinations,
collection of blood samples, and by questionnaires and
interview. The role of genetic factors and gene-environ-
ment interactions is studied using the candidate gene
approach and more recently genome wide association
studies, in which our data are often combined with those
from other studies in the context of the large collaborative
CHARGE consortium [47].
Clinical cardiovascular outcomes are collected during
our continuous follow-up and include non-fatal myocardial
infarction and cardiac death, revascularisations, heart fail-
ure, atrial fibrillation, gout, kidney failure, complications of
diabetes and pulmonary hypertension [33, 34, 41, 42, 48].
For additional EJE references concerning cardiovascular
disease see [49–67].
Endocrine diseases
Objectives
The main objective of the programme of endocrine epi-
demiology research is to study frequency and etiology of
major disorders of the endocrine glands (pituitary, repro-
ductive, thyroid, parathyroid, adrenal, and neuro-endocrine
The Rotterdam Study: 2010 objectives and design update555
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pancreas) and the musculoskeletal system. These include
endocrine and locomotor diseases, including diabetes
mellitus,osteoporosis, osteoarthritis,
deficiency, hypo- and hyper-thyroidism and parathyroid-
ism. The evaluation of risk factors for the above mentioned
conditions includes serum measurements (such as classical
hormones and other endocrine molecules) and genetic
determinants of endocrine factors and signalling pathways.
growth-hormone
Major findings
We have provided epidemiological documentation on the
hormone, growth factor and biomarker profiles in the
general population and determined the association with
several diseases. Within the topics of locomotor diseases
and disability we have reported that heart failure, COPD,
diabetes mellitus and chronic disorders leading to loco-
motor complaints, are risk factors which contribute con-
siderably to locomotor disability [68, 69].
In relation to osteoporosis we have determined the
incidence of vertebral [70] and non-vertebral fractures
[71], and the relationship between bone mineral density
(BMD), BMD change and the occurrence of fracture [71],
as well as with heel ultrasound measurements [72] and
bone resorption markers [73]. We have also studied the
relation between endogenous sex hormones and their
binding factors, with fractures [74], and showed that
increased homocysteine levels are a strong and indepen-
dent risk factor for osteoporotic fractures [75]. We studied
the relations between osteoporosis and other chronic dis-
eases like osteoarthritis [76], cancer [77], atherosclerosis
[78] and diabetes [79, 80], and provided indications for
the treatment and diagnosis of osteoporosis. Lastly, we
were part of several large consortia studying epidemio-
logical risk factors for osteoporosis [81–83]. For osteo-
arthritis (OA) we have shown how a new marker of
disease (CTX-II), is associated with the prevalence and
the progression of radiographic OA [84], independent of
known clinical risk factors. In addition, we have studied
different aspects of OA disease definition and classifica-
tion [85], evaluation of disease progression [86] and
determined the most prominent risk factors leading to OA
[87, 88].
We have also studied inflammatory aspects of endocrine
diseases like diabetes mellitus [89], and the relations of
hypo/hyperthyroidism to cardiovascular and neurological
disease [90]. We further examined the influence of genetic
variation in endocrine genes influencing hormone levels
[91], interaction of genetic factors in relation to fracture
risk [92, 93], to cardiovascular risk factors [94] and to
neurological conditions [95]. Our team has played a lead-
ing role in bringing together the global GENOMOS con-
sortium which has performed prospective meta-analyses
across many epidemiological cohorts for the most promi-
nent candidate genes for osteoporosis (see also Genetic and
biomarker studies).
Methods update
For all participants DXA-based BMD measurements of
the lumbar spine, dual hip and total body BMD, as well
as determination of body composition parameters are
assessed with a ProdigyTMtotal body fan-beam densi-
tometer (GE Lunar Corp, Madison, WI, USA). Hip
structural analysis [96] of DXA scans is available in a
subset of participants, while hip strength indexes (soft-
ware by GE Lunar) are determined for all scans. In the
current follow-up cycle we have introduced since 2009
iDXA measurements (GE Lunar) which performs lumbar
spine, dual hip and total body scans. Measurements
include L1–L4 BMD, bilateral total hip and femoral neck
BMD and total body BMD. From the total body scan, we
measure lean mass and fat mass body composition,
including total body, trunk, arm, legs, and android and
gynoid regions of interest.
X-ray examinations of vertebral bodies, hips, knees and
hand/wrist are obtained by a digitalized Fuji FCR system
(FUJIFILM Medical Systems) and assessed for the pres-
ence of fractures and/or degenerative changes of the joints.
Vertebral fractures are assessed using the qualitative
algorithm-based technique termed the ABQ method, an
update to the quantitative McCloskey–Kanis method [97].
Incident clinical fractures are obtained from computerized
records of the general practitioners and hospital registries
which are regularly checked by research physicians
who review and code the fracture information. Muscle
strength is assessed in all participants with a hand grip
dynamometer.
The incidence and progression of OA is done using
Kellgren scores obtained from X-rays of hip, knee, hands,
en spine. The complete set of X-rays is also available in
digitized form. Novel diagnostic assessments for OA are
currently underway using Magnetic Resonance Imaging
(MRI) on a large subset of the population. Several specific
biomarker assessments in blood/serum/plasma and urine
are done for the diagnosis and evaluation of risk factors of
endocrine and metabolic diseases.
Candidate gene and genome-wide association studies
(GWAs) are actively pursued within the scope of our
research for many of the above mentioned endocrine and
locomoter traits and diseases. Finally, validated question-
naires evaluating nutrient intake (e.g., calcium and vita-
mins) and activities of daily living, allow to evaluate the
role of environmental factors in endocrine conditions and
locomotor diseases of the elderly. For recent references in
EJE see [98–104].
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Liver diseases
Objectives
The objectives are to study the prevalence and incidence of
liver disease, as well as to investigate the role of genetic
and environmental determinants. The focus will be on liver
fibrosis and steatosis. Fibrinogenesis of the liver is most
probably not only the result of well known liver diseases,
such as viral hepatitis, alcoholic liver disease or non-
alcoholic fatty liver disease (NAFLD), but rather a com-
plex interaction between a genetic predisposition and these
liver disorders. Hepatologic focus in the Rotterdam Study
will be on the association between these known causes of
liver disease and the occurrence, magnitude, and progres-
sion of fibrosis in combination with genetic and environ-
mental effect modifiers. The incidence of steatosis in this
population will also be studied. Steatosis of the liver is the
hepatic manifestation of the metabolic syndrome (type 2
diabetes, abdominal obesity, dyslipidemia and arterial
hypertension) with interesting relations to other scientific
research topics in the Rotterdam Study.
Abdominal ultrasound
As of February 2009, trained technicians perform abdom-
inal ultrasonography in all RS-I-5 participants. Liver, bil-
iary tract, gall bladder, spleen, pancreas, and kidneys in
combination with Doppler examination of hepatic veins,
hepatic artery and portal vein will be evaluated. All images
are stored digitally and will be reevaluated by a physician
with expertise in hepatic ultrasonography.
Assessment of steatosis
Hepatic ultrasonography
The diagnosis of liver steatosis will be based on evident
ultrasonographic contrast between the hepatic and right
renal parenchyma (high-level echoes arising from the
hepatic parenchyma). Steatosis will be graded on a three-
grade scale (none, mild and severe) [105].
Assessment of fibrosis
Hepatic ultrasonography and elastography
Ultrasonographic evaluation of the liver parenchyma and
liver surface will be performed in order to assess severe
fibrosis and/or cirrhosis. Additionally sonographic signs of
portal hypertension will be studied (splenomegaly, venous
collaterals, portal vein diameter and flow, hepatic venous
flow, and the presence of ascites).
To assess and quantify the grade of fibrosis, trained
technicians will perform elastography in all participants.
This test measures non-invasively and quantitatively the
liver stiffness using a probe which includes an ultrasonic
transducer transmitting a vibration wave through the liver.
The velocity of the ultrasonic wave correlates directly with
tissue stiffness [106, 107].
Determinants of interest
The association between genetic and environmental factors
known to influence liver function and the occurrence of
steatosis and fibrosis will be studied. Additionally, the
association of these conditions with numerous determinants
will be studied such as, for example, age, gender, food
intake, concurrent alcohol intake, risk factors for viral
hepatitis, BMI, waist-to-hip ratio, serum glucose and dia-
betes mellitus, serum cholesterol and triglycerides, insulin
like growth factor (IGF), C-reactive protein and interleu-
kins. All clinical information will be obtained by interview
(updated with liver specific questions) and clinical
examination.
Neurological diseases
Objectives
Neuroepidemiologic research in the Rotterdam Study
focuses on the frequency, etiology and early recognition of
the most frequent neurologic diseases in the elderly,
including dementia, in particular Alzheimer disease, Par-
kinson disease and stroke. In neurodegenerative and cere-
brovascular disorders clinical symptoms typically become
manifest late in the disease course, the occurrence of
clinical disease does not reflect the underlying spectrum of
disease-related pathology, and most of the clinical syn-
dromes are etiologically heterogeneous. Therefore, an
additional research focus is on the causes and conse-
quences of pre-symptomatic brain pathology that can be
assessed with non-invasive imaging modalities.
Major findings
Neurodegenerative and cerebrovascular diseases are highly
frequent in the elderly. The prevalence increases from age
55 to 65 years to age 90 years and above from less than 1%
to over 40% for dementia [108], from less than 0.5% to
more than 4% for Parkinson disease [109], and from
approximately 1% to nearly 10% for stroke. The incidence
figures follow this pattern of a strong increase with age
over the entire age range, with the age-specific incidence of
dementia being identical for men and women at least until
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the age of 85 [110] but with men having a higher age-
specific incidence of both stroke and Parkinson disease
than women throughout the age range [111, 112].
Vascular pathology and vascular risk factors are asso-
ciated with worse cognitive performance [113], which also
translates in people with vascular pathology or risk factors
for vascular disease having an increased risk of dementia,
including Alzheimer disease [114]. Moreover, several life
style factors are associated with the risk of dementia and
Alzheimer disease [115–117], suggesting that onset of
dementia may at least partly be delayed or prevented.
Commonly used drugs may have a role in this [118].
The classical risk factors for stroke also predict risk of
stroke in the Rotterdam Study [119]. More recently iden-
tified risk factors, including inflammatory markers, may be
etiologically relevant but thus far add little to the identifi-
cation of people at risk [120]. Possibly underlying this is
that a large amount of stroke goes clinically undetected
[121]. Nearly 20% of elderly people have at least one silent
brain infarct, and thereby a nearly fourfold increased risk
of clinical stroke, a more than doubled risk of dementia
including Alzheimer disease, and an increased risk of
depression [121].
Neuroimaging reveals that brain pathology is widespread
[122] and can go clinically undetected for a long time. In
addition to the silent infarcts, many apparently healthy
elderly have ischemic changes in their cerebral white matter
that are associated with an increased risk of dementia, stroke
and depression. Also brain atrophy, especially of the hippo-
campus, is already present years before onset of even the
earliest sign of cognitive impairment or subjective com-
plaints. This emphasizes the need to shift the attention in
etiologic research of neurodegenerative and cerebrovascular
disease to the causes of pre-symptomatic and underlying
brain changes. Technological advances in image acquisition,
optimizedimaging sequences and automated post-processing
of multispectral MR data are major drivers of the rapid
developments in this field. The 3D T2* GRE sequence that
weuse wasspecifically developedtoincreasethe conspicuity
of cerebral microbleeds [123]. With this optimized sequence,
we found that microbleeds were present in nearly 20% of
persons overtheage of60 years,mountingtoa prevalenceof
over1 in3 inpersons aged80 years andolder;a much higher
prevalence than was reported hitherto [124]. Moreover, we
found supportive evidence that deep or infratentorial mi-
crobleeds reflect arteriolosclerotic angiopathy, whereas
strictly lobar microbleeds are caused by cerebral amyloid
angiopathy. These findings impact research into thecausesof
cerebral amyloid angiopathy, as well as fuel the ongoing
discussion about the safety of antithrombotic therapy in
persons with microbleeds [125]. Diffusion tensor imaging
(DTI) allows the assessment of the microstructural integrity
of white matter. White matter microstructure looses its
integrity with increasing age, but this can largely be
explained by presence of white matter atrophy and white
matter lesions [126]. Nevertheless, the microstructural integ-
rity in the normal appearing white matter and in white matter
lesions relates to cognitive function regardless of concurrent
macrostructural changes, emphasizing the importance of the
microstructural integrity of white matter [127].
Methods update
Assessment of dementia and Alzheimer disease
In the baseline and follow-up examinations participants
undergo an initial screen for dementia with the Mini Mental
State Examination (MMSE) and the Geriatric Mental
Schedule(GMS),followedbyanexaminationandinformant
interview with the Cambridge Examination for Mental
Disorders of the Elderly (CAMDEX) in screenpositives
(MMSE\26 or GMS[0), and subsequent neurological,
neuropsychological and neuroimaging examinations [108,
110]. Of subjects who cannot be reexamined in person,
information is obtained from the GPs and the regional
instituteforoutpatientmentalhealthcare.Aconsensuspanel
makes the final diagnoses in accordance with standard
criteria (DSM-III-R criteria; NINCDS-ADRDA; NINDS-
AIREN).
Assessment of Parkinsonism and Parkinson disease
Participants are screened in the baseline and follow-up
examinations for cardinal signs of parkinsonism (resting
tremor,rigidity,bradykinesia,orimpairedposturalreflexes).
Persons with at least one sign present are examined with the
Unified Parkinson’s Disease Rating Scale and a further
neurologic exam. PD is diagnosed if two or more cardinal
signs are present in a subject not taking antiparkinsonian
drugs, or if at least one sign has improved through medica-
tion, and when all causes of secondary parkinsonism
(dementia, use of neuroleptics, cerebrovascular disease,
multiple system atrophy, or progressive supranuclear palsy)
can be excluded [109, 112].
Assessment of stroke and stroke subtypes
History of stroke at baseline was assessed through inter-
view and verified in medical records. Putative incident
strokes get identified through the linkage of the study
database with files from general practitioners, the munici-
pality, and nursing home physicians’ files, after which
additional information (including brain imaging) is col-
lected from hospital records. A panel discusses all potential
strokes and subclassifies strokes into ischemic, hemor-
rhagic or unspecified [111, 120].
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Assessment of cognitive function
Global cognitive function is measured through the Mini
Mental State Examination (MMSE) in all surveys. From
the third survey (RS-I-3) onwards we added a 30 min test
battery that was designed to assess executive function and
memory function, and which includes a Stroop test, a
Letter Digit Substitution Task, a Word Fluency Test, and a
15 words Word List Learning test.
Rotterdam Scan Study: brain imaging within the Rotterdam
Study
In 1991, a random sample of 111 participants underwent
axial T2-weighted magnetic resonance (MR) imaging to
assesspresenceandseverityofwhitematterlesions[128].In
1995, a random sample of 563 non-demented participants
underwentbrainMRimaginginthecontextoftheRotterdam
Scan Study. The scanning protocol included series of axial
proton-density, T2-weighted and T1-weighted images, as
well as a high-resolution 3D-HASTE sequence [129]. From
August 2005 onwards, a dedicated 1.5 Tesla scanner is
operational in the research center of the Rotterdam Study,
and brain imaging is performed in all study participants
without contra-indications. The scanning protocol includes
4 high-resolution axial sequences (3D T1-weighted; 2D
PD-weighted; 2D FLAIR; and 3D T2* GRE), 2D phase-
contrast imaging, and diffusion tensor imaging (DTI).
Ophthalmic diseases
Objectives
The ophthalmic part of the Rotterdam Study focuses on
frequency and risk factors of chronic ophthalmic diseases
andonophthalmologicalcharacteristicsofsystemicdiseases
in the elderly. Emphasis is laid on age-related macular
degeneration, open angle glaucoma, retinal vessel diameters
and, recently, myopia and other refractive abnormalities.
Major findings
Age-related macular degeneration (AMD)
AMD prevalence increased exponential with age [130] and
AMD was the main cause of blindness in the high age-group
[131]. Risk factors that were found for AMD are smoking,
atherosclerosis, hyperopia [132–134]. The APO-E e-4 allele
showedaninverseassociationwithAMD[135].First-degree
relatives of patients with late ARM developed ARM at an
increased rate at a relatively young age [136]. The hetero-
geneityofgeneticriskamongAMDfamiliesisconsiderable,
and the proportion of high-risk families is relatively small
[137, 138]. The anticipated protective effect of statins on
AMD could not be substantiated in participants of the Rot-
terdam Study [139, 140]. A high dietary intake of beta car-
otene, vitamins C and E, and zinc was associated with a
substantially reduced risk of AMD [141]. Alcohol con-
sumption was not a risk factor for AMD [142]. The CFH
Y402H polymorphism accounted for a substantial propor-
tionofAMDcasesintheRotterdamStudyandparticularlyin
the presence of environmental and geneticstimulators of the
complementcascade[143,144].ThreecommonSNPs inthe
VEGF gene were not associated with AMD [145]. Cataract
surgery increased the risk of dry AMD, particularly in
homozygous CFH Y402H carriers [146]. Lipoprotein-asso-
ciated phospholipase A2 levels were not an important risk
factor for AMD despite the partly inflammatory pathogen-
esis of AMD [147].
Open angle glaucoma (OAG)
The prevalence of OAG was highly dependent on the
applied criteria. That was a major reason for proposing a
classification system without final, subjective adjudication
[148]. Systemic blood pressure and hypertension were
associated with elevated intraocular pressure but not with
prevalent OAG. Relatives of patients with OAG had a
strongly increased risk of glaucoma. Enlarged cup-disc
ratio was the earliest and most prominent feature of
familial aggregation. The incidence of OAG rose with
increasing age, most of these patients were unaware of
having OAG. The incidence of visual field loss rises five-
fold between 55 and 80 years in the general population.
Glaucoma is the main cause for visual field loss, followed
by stroke. Atherosclerosis, serum CRP level and diabetes
mellitus were not a risk factor for OAG. Calcium channel
antagonists were associated with open-angle glaucoma in
Rotterdam Study participants. These results do not support
the use of calcium channel antagonists for the treatment of
normal-tension glaucoma. Polymorphisms in the estrogen
receptor beta genes were associated with an increased risk
of OAG in men. Use of topical beta-blockers seems not to
be associated with excess mortality. We estimated that in a
white population with a low prevalence of pseudoexfolia-
tion, about one in 1,000 persons screened with a periodic
OAG screening program could be saved from bilateral end-
stage OAG.
Retinal vessel diameters
Larger retinal venular diameters were associated with
generalized atherosclerosis, inflammation and cholesterol
levels and may play their own independent role in pre-
dicting cardiovascular disorders [149]. Larger retinal
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venular diameters were related to incident stroke and
cerebral infarction [150], progression of cerebral small
vessel disease [151] and incident impaired glucose toler-
ance and diabetes mellitus [152]. Smaller retinal artery
diameters were related to incident hypertension [153].
Methods update
At baseline and follow-up examinations participants
undergo ophthalmic measurements including best corrected
ETDRS visual acuity, refractive error, Goldmann appla-
nation tonometry, keratometry, slitlamp examination of the
anterior segment and visual field testing. In pharmacolog-
ical mydriasis we made 35? color photographs of the
macular area, and 20? simultaneous stereoscopic imaging
of the optic disc and macular area. Analog fundus pho-
tography was replaced by stereoscopic digital imaging of
the macular area and optic disc since the third follow-up
examination. Optic nerve head analysis with a Heidelberg
Retina Tomograph, macular pigment density, and melanin
optical density measurements were added during the third
follow-up (RS-I-3). Fourier domain optical coherence
tomography of the macular area and optic disc, axial-length
and fundus autofluorescence measurements were added at
the fifth follow-up examination (RS-I-5).
Assessment of AMD
To diagnose AMD, 35? color photographs were taken of
the macular area of each eye at each follow-up examination
after pharmacologic mydriasis. The images were graded
with 12.59 magnification according to the International
Classification and Grading System for age-related macu-
lopathy [154].
Assessment of OAG
At baseline and follow-up, identical ophthalmic examina-
tions on each eye were performed that consisted of Gold-
mann applanation tonometry, visual field screening and
ophthalmoscopy, and stereoscopic fundus photography
with pharmacologic mydriasis. OAG was diagnosed using
an algorithm for the diagnosis of OAG based on presence
or absence of glaucomatous optic neuropathy (GON),
glaucomatous visual field loss, or both, yielding a classi-
fication as no, possible, probable, or definite OAG [148].
Assessment of retinal vessel diameters
Vessel measurements were performed on digitized fundus
color transparencies of the optic disc. For each subject, the
image with the best quality was analyzed with a semiau-
tomated system. Vessel measures were computed using the
improved Parr-Hubbard formula, adjusted for magnifica-
tion errors [149].
Psychiatric diseases
Objectives
The aim of the programme of psychiatric research in the
Rotterdam Study is to investigate the determinants, corre-
lates and consequences of common psychiatric problems.
The focus has been on depressive disorders, but anxiety
disorders, sleep disturbances, addiction to smoking, and
complicated grief are also being studied.
Major findings
Depression
Recently we completed our study of the incidence and
recurrence of depression [155]. During the follow-up per-
iod of 8 years on average, 566 depressive syndromes and
1,073 episodes of clinically relevant depressive symptoms
occurred. For depressive syndromes, the incidence rate was
7.0 (95% CI: 6.0–8.3) per 1,000 person-years and the
recurrence rate was 27.5 (95% CI: 23.7–32.1) per 1,000
person-years. The incidence and recurrence rates more than
doubled when episodes of depressive symptoms were
included. The recurrence rate of depressive syndromes was
equal for women and men, but all other rates were almost
twice as high for women compared with men. The rates did
not seem to change with age.
In a series of studies we found some evidence for the
vascular depression hypothesis. More severe coronary and
extra-coronary atherosclerosis were associated with a
higher prevalence of depression, as were cerebral haemo-
dynamic changes [156, 157]. However, we could not rule
out that earlier depressive episodes may have contributed
to the development of atherosclerosis. Moreover, our data
did not support a specific symptom profile of vascular
depression as previously defined [158].
Sleep
Weinvestigatedtherelationshipsofsleepdurationwithboth
cardiovascular risk factors and psychiatric disorders. We
found a marked U-shaped association of actigraphically
measuredtotalsleeptimewithBMIandobesity[159].Sleep
fragmentation also increased the likelihood of a higher BMI
andobesity,although,intheveryoldsleepfragmentationisa
risk factor for low cholesterol levels [160]. Self-reported
total sleep time was also examined in relation to depressive
disorders and anxiety disorders in more than 5,000 persons
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[161]. Again, both short and long sleepers were more likely
to be depressed or to have an anxiety disorder than persons
with a total sleep time of 7–8 h.
Anxiety
WefoundthatprevalentanxietydisordersfulfillingDSM-IV
criteria may be much less co-morbid with depressive disor-
ders than previously thought if the disorders are assessed
with different diagnostic instruments. On the other hand, a
history of depression is very common in persons with pre-
valent anxiety disorder (more than 50%, unpublished data).
Smoking
Typically, determinants of smoking cessation are studied by
comparing former with current smokers. We recently
introduced a prospective approach of studying smoking
cessation in 1,200 smokers (mean years of smoking:
40 years, minimum: 10 years). Smoking status was repeat-
edly assessed during follow-up every 3- to 4-years. In all
examination rounds participants were asked whether they
still smoked and if not, when they had stopped. Thus, an
individual could contribute any number of person-years
(maximum 14 person-year) to the analyses. In other words,
peoplewereclassifiedassmokersorquittersonaday-by-day
basis. This approach enabled us to detect genetic effect on
the incidence of smoking cessation [162].
Genetics of common psychiatric disorders
Several SNPs have been investigated as potential deter-
minants of depression, mostly with negative results.
However, we found that an ER-alpha polymorphism had a
substantial effect on anxiety but not on depression in
women [163]. In the past year, we have performed a series
of genome-wide association studies of the above psychi-
atric and psychological phenotypes, mostly as part of the
CHARGE consortium [47]. Whereas several analyses have
yielded no convincing genome wide significant results—
possibly because initial studies were underpowered, psy-
chiatric phenotypes do not present very homogenous enti-
ties, or are highly poly-genetic—the genome wide analyses
of the intermediate phenotype cortisol is more promising.
Replication in other general population studies and genetic
isolate studies is attempted and may yield new candidate
genes for psychiatric disorders.
Finally, ongoing psychiatric research projects examine
whether and how psychological well-being or psychiatric
problems contribute to survival. Most importantly, we are
interested in whether the effects are independent of con-
foundingbyphysicaldiseaseorcanbeexplainedbylifestyle,
immunological or hormonal regulation.
Methods update
In the first years of the Rotterdam Study I (RS-I-1, see
Fig. 1) psychiatric data collection was very limited. In the
second visit (RS-I-2) most participants were screened for
depressive symptoms and from the third examination
(RS-I-3) onwards, which began in 1997, depressive
symptoms and disorders are have been ascertained in all
participants. An assessment of anxiety disorders, sleeping
disturbances and complicated grief were added in the
fourth examination (RS-I-4) and have been included in all
follow-up visits of the Rotterdam Study I and II cohorts,
and in the baseline of the Rotterdam Study III cohort.
Major determinants
Psychiatric research in the Rotterdam Study focuses on
biological risk factors. The vascular depression hypothesis
wastestedwithdifferentmeasuresofatherosclerosis,arterial
stiffness and cerebral blood flow [156]. We also examined
whether blood levels of vitamins and fatty acids, immune
parameters, and markers of folate metabolism increased the
likelihood of depression [157, 164, 165]. In one ongoing
project, diurnal patterns of cortisol secretion are related to
psychiatric and other disorders such as subclinical athero-
sclerosis [166]. Studies of genetic polymorphisms and brain
morphology are underway [167]. Current data collection
includes a dexamethasone suppression test to measure
hypothalamic-pituitary-adrenal axis activity in all partici-
pants, which is unique in a population-based study. Also,
psychiatric problems and psychological traits such as hap-
piness, sleep duration and depression are increasingly stud-
ied as determinants of health and mortality [168].
Major outcomes
Information on depression is obtained from (a) psychiatric
examinations, (b) self-reported histories of depression,
(c) medical records, and (d) registration of antidepressant
use [155]. The psychiatric examination during follow-up
visits consists of a screening with the Center for Epide-
miologic Studies Depression Scale (CES-D), and in the
screen-positive participants a semi-structured interview
performed by a trained clinician [169]. The self-reported
history of depression includes standardized questions to
ascertain whether participants had experienced a depres-
sive episode, and if they had been treated. In order to
continuously monitor incidence of depression throughout
follow-up, trained research-assistants scrutinize the medi-
cal records of the general practitioners (GPs) and copy the
information about a potential depression.
The following anxiety disorders are assessed with a
slightly adapted Munich version of the Composite
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International Diagnostic Interview: generalized anxiety
disorder, specific and social phobia, agoraphobia without
panic disorder, and panic disorder [161, 170].
Sleep quality and disturbance is measured with the
Pittsburgh Sleep Quality Index. In addition, sleep duration
and fragmentation are assessed with actigraphy, a method
that infers wakefulness and sleep from the presence or
absence of limb movement [171]. In total, nearly 2,000
persons participated in this actigraphy study: they wore an
actigraph and kept a sleep diary for, on average, six con-
secutive nights.
The Inventory of Complicated Grief is used to identify
traumatic grief [172]. This is a condition distinct from
normal grief and bereavement-related depression, charac-
terized by symptoms like disbelief about the death and
searching for the deceased.
Respiratory diseases
Objectives
The objectives are to study the incidence of chronic
obstructive pulmonary disease (COPD), to investigate
genetic and environmental risk factors for COPD, and to
study the effect of COPD on mortality. COPD is defined as
a disease state characterized by airflow limitation that is
not fully reversible. The airflow limitation is usually both
progressive and associated with an abnormal inflammatory
response of the lungs to noxious particles or gases such as
tobacco smoke [173]. COPD is a worldwide leading and
still increasing cause of chronic morbidity and mortality
that will change from the sixth to the third most common
cause of death worldwide by 2020, whilst rising from
fourth to third in terms of morbidity [174].
Major findings
In the first cohort of the Rotterdam Study (RS-I) of 7,983
participants, 648 cases were identified with incident COPD
after a median follow-up time of 11 years. This resulted in
an overall incidence rate of 9.2/1,000 person-years (PY)
(95% CI, 8.5–10.0). The incidence rate of COPD was
higher among men (14.4/1,000 PY; 95% CI, 13.0–16.0)
than among women (6.2/1,000 PY; 95% CI, 5.5–7.0) and
higher in smokers than in never-smokers (12.8/1,000 PY;
95% CI, 11.7–13.9 and 3.9/1,000 PY; 95% CI, 3.2–4.7,
respectively). Remarkable was the high incidence in the
youngest females in the age category of 55–59 years
(7.4/1,000 PY; 95% CI, 4.1–12.6). For a 55 year-old man
and woman, still free of COPD at cohort entry, the risk to
develop COPD over the coming 40 years was 24 and 16%,
respectively [173].
Since COPD is not only affecting the lungs, but is also
characterised by extrathoracic manifestations, another line
of research focuses on the role of systemic inflammation in
the pathogenesis of COPD and its comorbidities. High
levels of hsCRP ([3 mg/l), a marker of systemic inflam-
mation, were associated with a significantly increased risk
of incident COPD (hazard ratio (HR), 1.7; 95% confidence
interval (95%CI), 1.16–2.49) compared with persons with
low CRP levels (\1 mg/l). The risk remained increased
after adjustment for potential confounders and introduction
of a potential latency period of 3 years. The risk was most
pronounced for former smokers (HR, 2.2; 95% CI, 1.12–
3.74). No CRP single nucleotide polymorphism or haplo-
type was associated with a significantly increased or
decreased COPD risk [175].
Methods update
Clinical assessment of COPD
For the validation of the COPD cases, we had access to
hospital discharge letters, files from the general practitio-
ners, spirometry reports and pharmacy dispensing data for
patients participating in the Rotterdam Study. Spirometry
was performed in the context of the first Rotterdam cohort
study (RS-I) in 3,550 participants. In addition, throughout
the entire study period, spirometries were also performed
on clinical indication by respiratory specialists and inter-
nists with a subspeciality in respiratory medicine. In the
absence of spirometry, all medical information of subjects
who used respiratory medication for at least 6 months and
all hospital discharge letters or mortality reports with a
coded diagnosis of COPD were reviewed. Definite COPD
was defined by a moderate-to-severe obstructive spirome-
try (FEV1/FVC\0.7 and FEV1\80% predicted), and/or
as COPD diagnosed by a specialist in internal medicine
(mainly respiratory physicians or internists with a subspe-
ciality in respiratory medicine) based upon the combination
of clinical history, physical examination and spirometry.
Probable COPD was defined by a mild obstructive spi-
rometry (FEV1/FVC\0.7 and FEV1C 80% predicted)
and/or as COPD diagnosed by a physician in another
medical speciality (e.g., a general practitioner).
Clinical outcomes are collected during our continuous
follow-up and include respiratory and non-respiratory
death, hospitalisations due to exacerbations of COPD as
well as moderate to severe COPD exacerbations treated
with systemic corticosteroids and/or antibiotics.
Pulmonary function testing
In the 5th round of the first cohort of the Rotterdam Study
(RS-I-5), the 3rd round of the second cohort (RS-II-3), and
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the 2nd round of the third cohort (RS-III-2), more detailed
and sophisticated techniques will be used to assess pul-
monary function. Since COPD encompasses small airway
disease(obstructive bronchiolitis)
destruction of the lungs (emphysema), both components
will be investigated by spirometry and measurement of
pulmonary diffusion capacity, respectively.
and parenchymal
Spirometry
Spirometry is performed by trained paramedical personnel
using an electronic spirometer with pneumotachograph
(Jaeger Masterscreen PFT, Cardinal Health, Hoechberg,
Germany), according to the American Thoracic Society
(ATS)/European Respiratory Society (ERS) guidelines.
Forced expiratory volume in one second (FEV1), forced
vital capacity (FVC) and FEV1/FVC ratio are measured;
the spirogram (volume-time curve) and maximal expiratory
flow-volume curve are also recorded. The interpretation of
spirometries is performed independently by two research
physicians; in case of discordance between both physi-
cians, a senior respiratory physician decides.
Measurement of pulmonary diffusion capacity
Measurement of diffusion capacity by single-breath deter-
mination of carbon monoxide (CO) uptake in the lung
(DL, CO) assesses the uptake of carbon monoxide (CO)
from the lung over a breath-holding period [176]. The
DL,CO is measured using the Jaeger Masterscreen PFT Pro
Diffusion apparatus (Cardinal Health, Hoechberg, Ger-
many) according to the guidelines of the ATS/ERS task
force on standardisation of lung function testing [176]. The
test gases used to calculate DL, CO include a tracer gas
(methane), to measure alveolar volume (VA), as well as
carbon monoxide (CO 0.3%). The remainder of the test gas
mixture includes O2and N2. For recent EJE references in
this area see [177–184].
Genetic and biomarker studies
Objectives
The first objective of the laboratory team is to collect, store
and manage the biological tissues mainly blood and urine
sampledintheRotterdamStudy.Thesecondobjectiveofthe
group concerns genotyping and assessment of biomarkers.
Major findings
Among the biomarker analyses our study documenting the
relationship between homocysteine and osteoporosis was
novel [185] and has since been widely replicated. Across
all research lines in the Rotterdam Study, several candidate
gene studies have also yielded new insights coming from
both exploratory studies as well as from collaborative
replication efforts. A unique feature of the Rotterdam
Study is exploited by studying the relationship between
pleiotropic gene variants and multiple diseases and disease-
related endpoints. For example, the studies on the promoter
region of the IGF-1 gene revealed a series of consistent
associations ranging from birth weight to diabetes [186],
while other consistent associations involve the estrogen
receptor alpha (ESR1) gene in relation to osteoporosis
[187], osteoarthritis, height, myocardial infarction [188],
age-at-menopause, and depression.
Rotterdam Study investigators are playing leading roles
in the emerging large global consortia focussed on
assessing the contribution of complex disease gene variants
by prospective meta-analysis across many epidemiological
cohorts [189], such as CHARGE, ENGAGE and the
GENOMOS/GEFOS [190, 191]. Since 2005 the genome
wide association study (GWAs) has changed the field of
complex genetics, and identified an ever growing list of
common variants contributing to disease risk and explain-
ing genetic variance of traits. Initial findings in the Rot-
terdam Study from individual collaborations replicating
early GWAs hits included CFH in age-related macula
degeneration [143], NOS1AP in QT interval [192], and
several SNPs involved in height, type 2 diabetes, and breast
cancer (collaboration with WTCCC investigators).
The Rotterdam Study has generated GWAs data for
almost the complete dataset summing to over 11,000 DNA
samples, and is involved as a major collaborative centre for
meta-analysis studies of GWAs data, including national
programs(RIDE,NGI-NCHA),
(GEFOS, TREATOA, ENGAGE), and voluntary collabo-
rations (GIANT, MAGIC, CHARGE). Especially, from the
CHARGE consortium (the Rotterdam Study together with
the Framingham Study, AGES, CHS, and ARIC) many
important publications have emerged on a wide variety of
phenotypes and diseases from all major research lines in
the Rotterdam Study [193–196].
EU-funded projects
Data collection, storage and management
At each examination, blood, serum, plasma (citrate, hepar-
ine, and EDTA based), sputum, and urine are collected.
Fasting blood samples are collected along with challenged
samples as part of a glucose tolerance test. Sputum is col-
lected before and after a dexamethasone-suppression test.
Sputum is frozen at -196?C before and after the challenge
and stored at -80?C. To obtain serum and plasma, tubes are
centrifuged according to a protocol standardising time and
conditions from the drawing of blood to centrifugation. All
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samplesaresnapfrozenat-196?Cusingliquidnitrogenand
storedat-80?C.RNAisisolatedfrombloodwithin5 hafter
sampling and stored at -20?C . DNA is isolated from blood
andextractionhasbeenrecentlyautomatedusingaHamilton
STAR pipetting platform and AGOWA magnetic bead
technology. DNA sample storage is in Matrix 2D-barcode
tubes in 96 well format. Overnight urine samples are col-
lected, frozen at -196?C and stored at -80?C. For data
management, an in-house customized laboratory manage-
ment system has been developed. Sample retrieval will be
automatedwithanin-housecustomizedlaboratory trackand
trace system.
Blood assessments
For all participants, serum cholesterol, HDL, LDL, tri-
glycerides, glucose and glucose levels are assessed. In
urine, micro albumin and creatinine are determined in all
participants. There have been a large number of specific
blood/serum/plasma-based biomarker assessments, includ-
ing steroids (e.g., estrogens, androgens, vitamin D, corti-
sol), interleukins, CRP, IGF1, insulin, iron-parameters
(iron, ferritin and transferrin saturation), fibrinogen,
homocysteine, folic acid, riboflavine, pyridoxine, SAM/
SAH ratio, cobalamine, Lp-PLA2, Fas/Fas-L, vitamins, a-
beta42/40 and thyroid hormones (TSH).
Genotyping facilities
Affiliated laboratory facilities include a medium/high-
throughput platform for candidate gene studies and GWAs
analyses. The facilities use high-end automated machinery
including a Caliper/Zymark ALH 3000 pipetting robot
(including a TwisterII, and integrated plate sealer, plate
reader (OD 260/280), a Tecan EVO 150 Freedom pipetting
robot, a Deerac Equator NS808 nanoliter liquid dispenser,
15 electronic PCR machines (ABI 9700, 2 9 384), an
ABI7900HT Taqman machine (running 1 ng gDNA in 2 ll
reactions), a WAVE 3500HT dHPLC, Sequenom iPlex,
and two ABI3100 sequencing machines. DNA sample
handling is centred on 384-well plates. Candidate gene
studies are done mostly using Taqman and Sequenom
genotyping with throughputs at 30,000 genotypes per day.
Continuous efforts are focussed on reducing the required
amount of genomic DNA which is now down to 1 ng per
genotype. GWAs genotyping studies are based on 500 K
Affymetrix arrays (a pilot project of 450 women) and 550
and 610 K Illumina arrays for the complete Rotterdam
Study cohort encompassing over 11,000 DNA samples.
The in-house GWAs genotyping facility has been partly
sponsored by NWO investment grants (911-03-012;
175.010.2005.011), is part of the Erasmus Medical Center
Biomics core facility, and serves as knowledge center for
polymorphism analysis attracting national and international
interested parties, both academic and industrial.
Candidate gene studies
We have genotyped over 300 individual polymorphisms as
part of candidate gene studies across the complete cohort
and conducted a large number of candidate gene studies in
the Rotterdam Study. These mostly concern individual
potentially functional single nucleotide polymorphisms
(SNPs) per gene, but sometimes also haplotype tagging
SNPs (e.g., ESR1, ESR2, HSD11B1, fibrinogen), and also
high density SNP screening (e.g., the vitamin D receptor
gene). The candidate genes studied include the apolipo-
protein Egene(APOE),
enzyme (ACE), the gene encoding angiotensinogen (AGT),
angiotensin II type 1 receptor (AT1R) gene, G protein
beta3 (GNB3), adducine gene, Cholesteryl Ester Transfer
Protein (CETP), Hepatic Lipase, Phosphodiesterase 4D
(PDE4D), ALOX5AP encoding 5-lipoxygenase activating
protein, a polymorphism in the regulatory region of the
Insulin-like Growth Factor 1 (IGF-1) gene, the hemo-
chromatosis (HFE) gene, Complement factor H gene
(CFH), and several polymorphisms in genes from the
estrogen-, thyroid-, cortisol-, vitamin D-, IGF-, and Wnt-
signalling patways, the homocysteine pathway, and several
matrix molecules.
the angiotensin-converting
Genome wide association studies (GWAs)
Genome Wide Association studies (GWAs) are based on
genotyping epidemiological cohorts with ultra-high density
SNP arrays with up to 1 million SNPs. The method has been
shown to successfully identify common genetic factors for
hundreds of traits and diseases (see www.genome.gov/
GWAstudies). Through a large grant from the Dutch
research organisation NWO one of the world’s largest
GWAs datasets has been facilitated involving over 11,000
DNA samples from the Rotterdam Study cohorts. This
GWAsdatasetisbasedontheIllumina550and610 Karrays
and will be useful forall research lines within the Rotterdam
Study. In addition, it will also serve as a control GWAs
dataset for other research centers in and outside The Neth-
erlands for both SNP frequencies as well as copy number
variations(CNVs).Inadditionourgrouphasalsobeenactive
in developing new software for GWAs analyses [197].
New developments
The new development in the basic sciences will be to move
to transciptomic studies and proteomic studies. With this
view, the data collection protocol has been adjusted, stan-
dardizing blood collection. Further new developments
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target lipidomics and glycomic research. Other references
may be found elsewhere [198–205].
Pharmaco-epidemiologic studies
Objectives
A major objective of the pharmaco-epidemiologic studies is
to investigate the role of drugs as determinants of disease in
the Rotterdam Study. This includes studying efficacy and
effectiveness of drugs, as well as adverse reactions to drugs.
Major findings
Important findings have been published on pharmaco-epi-
demiological topics concerning the main outcomes in the
Rotterdam Study. Studies about the association between
dementia, and antihypertensive drugs [206] and NSAIDs
[118] have strongly suggested a protective effect of both
groups of drugs. Several studies have been performed on
cardiovascular topics [207–209]. In one of these studies,
NSAIDs were associated with an increased risk of heart
failure. In line with the suspicion that QTc-prolonging
drugs may cause sudden cardiac death, it was demonstrated
in the Rotterdam Study that a prolonged QTc is indeed an
important risk factor [208]. Furthermore, in one study it
was demonstrated that high-dose corticosteroids increase
the risk of atrial fibrillation [209]. In the important area of
locomotor diseases, studies have demonstrated that thiazide
diuretics protect against hip fracture [210] and that statins
reduce the risk of vertebral fracture [211]. On the other
hand, the risk that long-term use of certain NSAIDs may
aggravate signs of osteoarthritis has been emphasized
[212]. In the area of ophthalmic diseases, a protective
effect of cholesterol-lowering agents on macular degener-
ation has been studied [139, 140]. In other areas, such as
pharmacogenetics and other causes of interactions between
drugs, several important findings have been published [192,
213–234].
Methods update
For several reasons, a drug is a highly attractive determinant
in clinical epidemiologic research. First, drugs are probably
the most important therapeutic intervention in health care.
Despite rigorous clinical research before registration, many
important effects of drugs are discovered after marketing.
Second, all marketed drugs have proven biological activity,
meaningthat itconcernsadeterminant which reallymatters.
Third, and as a consequence of the availability of complete
medication histories in Dutch health care, the role of drug
exposure can be assessed in a detailed way.
In the Rotterdam Study, there is an almost complete
coverage of the population as of January 1, 1991, thanks to
the fact that all pharmacies which serve the Ommoord
district are on one computer network. To date, almost three
million prescriptions have been delivered to the population
of the Rotterdam Study and of each prescription, details are
available about the product name and contents, ATC-code,
dosage and duration of drug therapy.
Drugs are a group of determinants which can be studied
in association with a large variety of diseases. In the Rot-
terdam Study there is a strong interest in the association
between drugs and the cardiovascular, neurological,
endocrine, and ophthalmic diseases which have been the
main topics since its start. However, there is also important
information about the association with psychiatric diseases,
cancer, and chronic obstructive pulmonary disease. More-
over, important information about secondary outcomes,
such as drug blood levels, other laboratory information,
and information about hospital discharge diagnoses, is
gathered on a continuous basis to facilitate pharmaco-epi-
demiological studies. Further EJE references can be found
in [235–238].
Management
The Rotterdam Study is directed by a Management Team
comprising Jan Heeringa, MD, PhD, study coordinator,
Eric Neeleman, head IT, Frank van Rooij, MSc, head data-
management, and the scientific principal investigators
Albert Hofman (PI Rotterdam Study, chairman), Monique
Breteler (PI Neurological diseases), Cornelia van Duijn
(PI Genetic studies), Harry Janssen (PI Hepatic diseases),
Gabrie ¨l Krestin (PI Radiology), Ernst Kuipers (PI Internal
Medicine), Bruno Stricker (PI Pharmaco-epidemiology),
Henning Tiemeier (PI Psychiatric diseases), Andre ´ Uitterlinden
(PI Genome wide analysis), Johannes Vingerling (PI Oph-
thalmic diseases) and Jacqueline Witteman (PI Cardiovas-
cular diseases). The study of respiratory diseases is
conducted in close collaboration with Prof Guy Brusselle,
Department of Respiratory Medicine, University of Gent,
Belgium.
Acknowledgments
Medical Center and Erasmus University Rotterdam, The Netherlands
Organization for Scientific Research (NWO), The Netherlands Organi-
zation for Health Research and Development (ZonMw), the Research
Institute for Diseases in the Elderly (RIDE), The Netherlands Genomics
Initiative, the Ministry of Education, Culture and Science, the Ministry of
Health, Welfare and Sports, the European Commission (DG XII), and the
Municipality of Rotterdam. The contribution of inhabitants, general
practitioners and pharmacists of the Ommoord district to the Rotterdam
Study is gratefully acknowledged. The authors also gratefully acknowl-
edgethecontributionsofpreviousprincipalinvestigatorsoftheRotterdam
Study,includingFrankvandenOuweland(Endocrinediseases),Diederick
The Rotterdam Study is supported by the Erasmus
The Rotterdam Study: 2010 objectives and design update 565
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Grobbee(Cardiovasculardiseases),PaulusdeJong(Ophthalmicdiseases)
and Huibert Pols (Endocrine diseases). The contribution of Guy Brusselle
to the study of respiratory diseases is also gratefully acknowledged.
Open Access
Creative Commons Attribution Noncommercial License which per-
mits any noncommercial use, distribution, and reproduction in any
medium, provided the original author(s) and source are credited.
This article is distributed under the terms of the
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