Change in Abdominal Obesity & Change in Abdominal Obesity & Risk of Coronary CalcificationRisk of Coronary Calcification

Siamak Sabour, MD, MSc, DSc, PhD, PostdocClinical Epidemiologist

Persian International Epidemiology Network (PIEPNET)

SCIENTIFIC BACKGROUND

• 1994: M.D, I.R. Iran

• 2004: M.Sc, Clinical Epidemiology, Erasmus MC, The Netherlands

• 2006: D.Sc, Clinical Epidemiology, Erasmus MC, The Netherlands

• 2007: Ph.D, Clinical Epidemiology, UMC Utrecht, The Netherlands

• 2008

• Post doc Cardiovascular Epidemiology

Thomas Jefferson University, Philadelphia, PA, USA

• Post doc Pharmacoepidemiology

University of Pennsylvania, Philadelphia, PA, USA

• 2008 until now

Assistant Prof of Clinical Epidemiology & Medicine

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Introduction

• Obesity is a major health problem in industrialized countries.

• The prevalence of overweight and obesity has increased dramatically in last decades.

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Introduction

• Visceral or abdominal obesity is an important indicator of cardiovascular risk.

• Atherosclerosis is a key factor in the pathogenesis of cardiovascular disease.

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Introduction

• Atherosclerosis in the coronary arteries

(CAC) can be accurately and

reproducibly assessed with Multi-

Detector Computed Tomography (MDCT)

in a non-invasive way.

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Introduction

• CAC is increasingly used as a marker of

disease risk or of subclinical atherosclerosis.

• The presence of CAC is a significant

predictor of subsequent cardiovascular

disease and total mortality.

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Introduction

• Randomized Controlled Trials (RCT) have

indicated that weight loss may benefit levels

of risk factors; however, trials were usually of

modest duration.

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PURPOSE

• To determine the impact of change in

abdominal obesity, as assessed by

change in WHR during 9 years, on risk

of coronary artery calcification (CAC).

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DESIGN

Cohort (longitudinal) study

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SUBJECTS

573 postmenopausal women

selected from a population

based cohort study.

(PROSPECT study)

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METHODS

Data on WHR were collected at

baseline (1993-1997) and follow-up

(2002-2004).

At follow-up, the women underwent a

multi-detector computed tomography

(MDCT) (Philips Mx 8000 IDT16) to

assess coronary artery calcium (CAC). 11Sabour S, MD, MSc, DSc, PhD, Postdoc

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METHODS

The Agatston score was used to quantify

coronary artery calcium.

Logistic regression models were used

to evaluate the relations under study.

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METHODS

Change in WHR was categorized

into four groups:

• Low at baseline - Low at follow-up (Low was defined as below the median)

• High-Low

• Low-High

• High-High

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RESULTS

• Compared to subjects whose WHR

remained below the median of the

distribution at both occasions, those

with a WHR above the median at both

occasions had a 2.7 [95% CI 1.8-4.0]

fold increased risk of CAC.

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RESULTS

• Women whose WHR rose over the 9

year period from below the median to

above the median had a 2.5 [95%CI

1.4-4.5] fold increased risk of CAC.

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Risk factors Mean (SD) _______________________________ Baseline Follow-up (1993-1997) (2002-2004)

P value

Age (year) 57.2 ± 5.2 66.8 ± 5.5Body Mass Index (Kg/ m2 ) 25.6 ± 4.0 26.7 ± 4.4 <0.001Waist circumference (cm) 82.3 ± 9.4 86.1 ±11.2 <0.001Hip circumference (cm) 105.1 ± 8.2 102.1 ± 9.3 <0.001Waist to Hip Ratio 0.78 ± 0.05 0.84 ± 0.07 <0.001Systolic blood pressure (mmHg) 131 ± 19 136 ± 21 <0.001Diastolic blood pressure (mmHg) 78 ± 10 72 ± 9 <0.001Pulse pressure (mmHg) 52 ± 14 64 ± 16 <0.001Cholesterol (mmol/l) (n=95) 5.9 ± 0.9 6.2 ± 1.0 0.078LDL cholesterol (mmol/l) (n=95)

4.0 ± 0.9 4.2 ± 0.9 0.118

HDL cholesterol (mmol/l) (n=95)

1.6 ± 0.4 1.4 ± 0.4 <0.001

Glucose (mmol/l) (n=90) 4.3 ± 0.9 5.6 ± 1.0 <0.001Current smoking (%) 18 11 <0.001Former smoking (%) 37 44 <0.001Hypertension § 140/90 (%) 28 27 0.178Diabetes (%) 1 6 <0.001

General characteristics of study population (n=573)

Low Density Lipoprotein, High Density Lipoprotein§ Based on systolic, diastolic and history of having hypertension in baseline questionnaire

General characteristics of study population (n=573)

Low Density Lipoprotein, High Density Lipoprotein§ Based on systolic, diastolic and history of having hypertension in baseline questionnaire

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Age- adjusted relation between cardiovascular risk factors measured at 1993-1997 (baseline) and measured at 2004-2005 (follow-up) and coronary

calcification measured in 2004-2005

RISK FACTORS CORONARY CALCIFICATION OR (95% CI)

Baseline Follow-up Age * § 1.86 (1.54 – 2.25) 1.88 (1.56 – 2.28) Body Mass Index § 1.09 (0.91 – 1.31) 1.11 (0.93 – 1.32) Waist circumference § 1.20 (1.01 – 1.45) 1.28 (1.07 – 1.53) Hip circumference § 0.99 (0.77 – 1.10) 1.01 (0.93 – 1.10) Waist to Hip Ratio § 1.44 (1.21 – 1.72) 1.54 (1.27 – 1.86) Systolic Blood Pressure § 1.42 (1.16 – 1.74) 1.41 (1.15 – 1.71) Diastolic Blood Pressure § 1.40 (1.15 – 1.70) 1.46 (1.22 – 1.75) Pulse pressure § 1.27 (1.04 – 1.56) 1.22 (1.00 – 1.49) Cholesterol § 1.39 (0.87 – 2.19) 1.06 (0.88 – 1.26) LDL cholesterol § 1.45 (0.91 – 2.31) 1.22 (1.02 – 1.46) HDL cholesterol § 0.88 (0.56 – 1.40) 0.80 (0.65 – 0.97) Glucose § 1.31 (0.78 – 2.21) 1.07 (0.91 – 1.25) Current smoking 2.86 (1.71 – 4.77) 6.17 (2.90 – 13.09) Former smoking 1.03 (0.73 – 1.48) 1.12 (0.79 – 1.60) Hypertension 140/90 (%) 1.58 (1.04 – 2.40) 1.73 (1.07 – 2.81) Diabetes (%) 0.30 ( 0.03 – 2.84) 1.29 (0.60 – 2.74) CAC=coronary artery calcification, LDL= Low Density Lipoprotein, HDL=High Density Lipoprotein

* No adjustment for age, § per standard deviation

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Baseline Follow-up Participants OR (95% CI)

Body Mass Index Model 1 Model 2

Low Low 250 1 1

High Low 22 0.97 (0.39-2.46) 0.83 (0.32-2.12)

Low High 45 1.36 (0.68-2.71) 1.21 (0.60-2.46)

High High 255 1.12 (0.77-1.63) 1.13 (0.80-1.65)

Waist circumferenceLow Low 242 1 1

High Low 50 1.46 (0.70 – 3.04) 1.35 (0.64 – 2.84)

Low High 38 2.15 (1.09 – 4.23) 1.94 (0.97 – 3.86)

High High 235 1.53 (1.04 – 2.26) 1.50 (1.01 – 2.23)

Hip circumference

Low Low 246 1 1

High Low 55 1.17 (0.63 – 2.19) 1.14 (0.60 – 2.15)

Low High 33 1.06 (0.48 – 2.37) 1.05 (0.47 – 2.35)

High High 231 0.95 (0.65 – 1.40) 0.93 (0.63 – 1.38)

Waist to Hip RatioLow Low 227 1 1

High Low 49 1.62 (0.83-3.16) 1.70 (0.87-3.33)

Low High 71 2.48 (1.38-4.46) 2.45 (1.35-4.50)

High High 224 2.65 (1.76-3.99) 2.56 (1.70-3.89)

Risk of coronary calcification in categories of change in obesity markers (BMI, WC, HC and WHR)

Model 1= Adjusted for AgeModel 2= Adjusted for Age and Smoking at baseline.

Risk of coronary calcification in categories of change in obesity markers (BMI, WC, HC and WHR)

Model 1= Adjusted for AgeModel 2= Adjusted for Age and Smoking at baseline.

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CONCLUSION

Persistent abdominal obesity

as well as an

increase in abdominal fat over time

relates to an increased

risk of coronary atherosclerosis. 21Sabour S, MD, MSc, DSc, PhD, Postdoc

Acknowledgments

Prof. Diederick. E. Grobbee, MD, PhD

Prof. Mathias Prokop, MD, PhD

Dr. Yvonne. T. van der Schouw, PhD

Prof. Michiel. L. Bots, MD, PhD

1. Julius Centre, University Medical Centre Utrecht, The Netherlands

2. Radiology Department, University Medical Center Utrecht, The Netherlands

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CONCLUSION

Changes in Waist-to-Hip Ratio (WHR)

relates to an

increased risk of CAC.

However, Body Mass Index (BMI), has no

effect on that.

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