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Body Mass Index and Initial Presentations of Cardiovascular Diseases (CALIBER)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01704300
Recruitment Status : Completed
First Posted : October 11, 2012
Last Update Posted : October 11, 2012
Information provided by (Responsible Party):
Harry Hemingway, University College, London

Brief Summary:
The association between obesity and cardiovascular disease (CVD) has mostly been studied using broad endpoints or have focused on cause-specific mortality. The investigators aim to compare the effect of body mass index (BMI) on different types of initial presentation of CVD.

Condition or disease
Abdominal Aortic Aneurysm Acute Myocardial Infarction Stroke Heart Failure Peripheral Arterial Disease Angina

Detailed Description:

Obesity has many detrimental effects on the cardiovascular system that can manifest in a range of clinical presentations. Many of these are mediated by frequently coexisting conditions such as diabetes, hypertension and dyslipidemia but there are also direct, progressive effects on the arteries and the heart muscle. As evident from autopsies, even from early adulthood the degree of coronary artery disease (CAD) correlates with the BMI and particularly the amount of abdominal fat. The multiple mechanisms by which obesity exerts its effects are still being elucidated.

Previous studies have assessed the effect of obesity on cause-specific mortality. Here the investigators analyze association of BMI with the first symptomatic presentation of cardiovascular disease across any phenotypes, to which the investigators refer to as "initial presentation" to distinguish from first presentation within a specific phenotype. For example, an initial presentation with myocardial infarction is an MI which is not preceded by stable angina, ischemic stroke or any other phenotype, rather than the first MI in a possible series of MIs, as is commonly used in other studies.

Adjustments The key risk factor of interest is baseline BMI, which the investigators define as the most recent measurement of BMI recorded up to 2 years prior to cohort entry date. BMI will be analyzed based on the following categories: underweight (<18.5 kg/m2), healthy (18.5 to 24 kg/m2), overweight (25 to 29 kg/m2), moderately obese (30 to 34 kg/m2), morbidly obese (>35 kg/m2). The healthy BMI category will be used as the reference in regression models.

Associations with BMI will be adjusted for age, sex, ethnicity, social deprivation, smoking, diabetes, and systolic blood pressure, total cholesterol (TCHOL) and high-density lipoprotein cholesterol (HDL). All baseline covariates will be obtained from within a 2 year window prior to study entry.

Statistical analyses Cause-specific Cox models will be used to measure the association between BMI categories and endpoints of interest. Multiple imputation will be used to replace missing values in prognostic factors. The investigators will estimate lifetime risk for each endpoint over time adjusting for competing risks.

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Study Type : Observational
Actual Enrollment : 2240000 participants
Observational Model: Cohort
Time Perspective: Retrospective
Official Title: Body Mass Index and Initial Presentations of Cardiovascular Diseases
Study Start Date : January 2001
Actual Primary Completion Date : March 2010
Actual Study Completion Date : March 2010

Resource links provided by the National Library of Medicine

CALIBER Healthy Cohort
We will report findings from the CALIBER (CArdiovascular disease research using Linked BEspoke studies and Electronic Records) collaboration where we linked primary care data (from the General Practice Research Database [GPRD]) to three further sources of electronic health records: the Myocardial Ischemia National Audit Project registry (MINAP),cause specific discharge data from Hospital Episodes Statistics (HES) and cause specific mortality from the Office for National Statistics (ONS).

Information from the National Library of Medicine

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Ages Eligible for Study:   30 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
The cohort we will use in the present analysis has been drawn from patients across 225 practices in England contributing data to GPRD, covering approximately 5% of the UK population (Figure 1). The study period is 1st January 2001 to 25th March 2010 (the date of the last GPRD data submission). To allow time for medical history and risk factors to be measured and recorded we require that patients enter the cohort after having completed at least 1 year of registration with their current practice during which the practice provides data that meet research quality criteria. Patients are followed up from the date they become eligible to be included in the cohort until the earliest date among a) the date of an initial presentation with one of the endpoints of interest, b) the date of leaving the practice or c) the date of last data submission from their practice.

Inclusion Criteria:

  • Baseline age ≥30 years

Exclusion Criteria:

  • prior atherosclerotic disease or stroke

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01704300

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United Kingdom
University College London
London, United Kingdom, WC1E 6BT
Sponsors and Collaborators
University College, London
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Responsible Party: Harry Hemingway, Harry Hemingway, FRCP, University College, London Identifier: NCT01704300    
Other Study ID Numbers: CALIBER 10_14
First Posted: October 11, 2012    Key Record Dates
Last Update Posted: October 11, 2012
Last Verified: October 2012
Keywords provided by Harry Hemingway, University College, London:
Abdominal aortic aneurysm
Acute Myocardial Infarction
Coronary heart disease not otherwise specified
Haemorrhagic stroke
Heart failure
Ischaemic stroke
Peripheral arterial disease
Stable angina
Unheralded coronary death
Unstable angina
Ventricular arrhythmias, cardiac arrest and sudden cardiac death
Transient Ischemic Attack
Additional relevant MeSH terms:
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Heart Failure
Myocardial Infarction
Aortic Aneurysm
Peripheral Arterial Disease
Peripheral Vascular Diseases
Aortic Aneurysm, Abdominal
Cardiovascular Diseases
Vascular Diseases
Heart Diseases
Pathologic Processes
Myocardial Ischemia
Aortic Diseases
Arterial Occlusive Diseases