CV Risk Factors in South Asians of Canada

Sonia Anand

McMaster University

Feb 21, 2013

North America

Australia

Africa

Asia

Europe

Middle East

South and Central America

Excess Coronary Heart Disease in South Asian Migrants

Mortality for CHD and CancerAge 35 – 74(1979-1993)

0

20

40

60

80

100

120

140

160

CH

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Can

cer

Mo

rtal

ity

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Rat

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South Asian Chinese European

CHD

Cancer

Sheth T et al, CMAJ 1999

South Asian 7%

Black 4%

Other 9%

White 75%

Statistics Canada, 2006

Ethnic Profile in Ontario

Changes in Risk Factors with Migration

51.6

19.4

9.3

1.8

13.5 16.8

6.6

23.519

1

19.1

25.226.3

0

5

10

15

20

25

30

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10

20

30

40

50

60

Rurual India Urban India Canada

BMI

% R

isk F

acto

r

Smoke

DM

HTN

BMI

36 lbs42 lbs

n=972 n=342n=775

1. Weight gain 2. pre-Diabetes 3. Diabetes 4. Heart Disease

Evolution of risk factors in South Asians

• Lipids• Blood Pressure

5.? Some Cancers

6

Metabolic Syndrome Phenotype: A Cluster of Metabolic Abnormalities

• Abdominal Adiposity

• Dysglycemia• HDL Cholesterol• Triglycerides• +/- Elevated BP

Associated with a significant increase in type 2 diabetes and CHD

Visceral Adipose Tissue

Subcutaneous Adipose Tissue

Age-Adjusted Prevalence of Metabolic Syndrome in Canada

45.4

26.8

15.9

28.8 28.325.2

14.3

7.1

41.3

23.4

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101520253035404550

Overall Chinese Euro SouthAsian

Aboriginal

Women

Men

Age-AdjustedAnand et al Circulation 2003

0.5 1 2 4 8 16OR (99% CI)

INTERHEART: MS and MI by Region

Region % Contr OR (99% CI) PAR (99% CI)

Overall 26.1 2.69 (2.48,2.92) 29.2 ( 27.1, 31.3)

W Europe 16.7 3.86 (2.61,5.70) 36.0 ( 27.5, 45.4)

C/E Europe 32.0 1.82 (1.46,2.26) 20.4 ( 14.3, 28.2)

Middle E/Egypt 35.7 2.53 (2.08,3.08) 34.8 ( 29.1, 41.1)

Africa 24.6 4.02 (2.76,5.86) 41.7 ( 32.6, 51.4)

South Asia 26.9 2.72 (2.18,3.39) 31.6 ( 25.9, 37.9)

China /H.K. 13.9 2.27 (1.89,2.73) 15.1 ( 12.1, 18.7)

S.E. Asia/Japan 22.4 5.59 (4.22,7.41) 50.0 ( 43.5, 56.6)

Aust/N. Z. 26.4 2.20 (1.30,3.72) 22.0 ( 10.5, 40.3)

South Am./Mex. 36.3 2.74 (2.18,3.44) 40.3 ( 33.1, 47.9)

North Am 27.4 2.30 (0.97,5.47) 21.5 ( 5.5, 56.3)

Mente et al JACC

Summary of Risk Factors

• 1) Increased body fat• 2) Tendancy toward central adiposity• 3) Visceral Fat excess• 4) Fatty liver• 5) Low HDL, High LDL, High TRGS• 6) Increased Diabetes• 7) Smoking is lower

Summary of Presentation, Diagnosis, and Treatment

• Presentation time to hospital with chest pain symptoms is later in SA

• Management of acute coronary syndromes is similar

• Case fatality rate is similar • Long-term morbidity, mortality appears

similar• Lower attendance at Cardiac Rehab

Pregnancy and Early Childhood

Adult Metabolic Syndrome

Interventions to Change Health

Behaviours

Individual

Community Level

SouTh Asian BiRth CohorTEarly Life Determinants

“Thin-fat” baby

• Newborns, relatively small at birth (BW < 2.9 kg) reported to have greater subscapular skin fold thickness, which is shown to correlate well with truncal obesity

• This adiposity tracks to 4 years of age• An increase of BMI of 1 SD from 2 to 12

years of age, increased the odds ratio for disease (IGT / DM) by 1.36. in young adults

Krishnaveni GV, Hill JC, Veena SR, Fall CHD. Indian Pediatr 2005; 42: 527-538

New Eng J Med 2004; 350: 865-875.

LBW persists in South Asian babies in UK

• X- sectional data record linkage 2005 – 2006 n=861,654 births of white, or South Asians

• 1st generation: Born in Indian subcontinent

• 2nd generation: Born in England/Wales

Singleton Birth Weights

N = 772,128 1st Generation 2nd Generation

White Mean = 3457g

Bangladesh Mean = 3074g 13,261Mean = 3084g

3,015Mean = 3026g

Indian Mean = 3089g 15,733Mean = 3105g

11,368Mean = 3062g

Pakistani Mean = 3130g 28,566Mean = 3148g

17,583Mean = 3097g

Leon, J Epidemiol Community Health 2012;66:544-61

Birth Weight by Maternal Region of Birth (Canada and South Asia only). Ontario, 2002-2006 Combined

Risk of Gestational Diabetes Mellitus in Association with Maternal Place of Birth

Canad

ian-B

orn

Indu

stria

lized

Nat

ions

Sub S

ahar

an A

frica

Carrib

ean

East A

sia

South

Asia

0

1

2

3

4 Country of Birth

a Odds ratios were adjusted for maternal age (continuous in years), number of livebirths, multifetal pregnancy, place of residence, neighborhood income quintile, and fiscal year of delivery. b Reference category.

Epidemiology: November 2011 – Volume 22 – Issue 6 – pp 879-880.

Rel

ativ

e R

isk

of

DM

, ob

esit

y, C

VD

Low HighBirth Weight Higher Risk with

LOW Birth Weight

Higher Risk with HIGH Birth

Weight

• Placental insufficiency • Maternal undernutrition• Hypoxia (smoking, anemia,

altitude) • Genetics

• Maternal diabetes • Obesity• Excess gestational

weight gain • Genetics

Both low birth weight and high birth are associated with long-term metabolic disease risk for offspring

Diverse Environments

250 Mothers/Babies

250 Mothers/Babies

1000 Mothers/Babies

Rural India Urban India Urban Canada

DIETARY DIFFERENCES (WEIGHT GAIN)

ACCESS to PRIMARY CARE

PSYCHSOCIAL SRESS, SOCIAL SUPPORT

GENETIC/EPIGENETIC FACTORS20

Birthweight among GA > 37 weeks

START FAMILY (EC)3.15

3.2

3.25

3.3

3.35

3.4

3.45

3.5

3.55

3.6

Series 1

In singleton newborns with a gestational age >=37 weeks

START: Is thin fat phenotype Observed in Canada?

South Asian FAMILY (EC)2.6

2.7

2.8

2.9

3

3.1

3.2

3.3

3.4

%fat/kg BW

%fat/kg BW

In singleton newborns with a gestational age >=37 weeks

Epigenetic

• Maternal Exposures linked to DNA methylation in offspring:– Smoking– Depression– Under or over nutrition

Regions of Genome associated with Birth Weight

• Development and morphagenesis • Cell Cycle/Cell division• Metabolism and biosynthesis• Not imprinted regions or housekeeping

genes• 60% methylation discordance between

heavy and light birth weight babies

Explanations

• 1) Genetic- Transgenerational, DNA inherited

• 2) EpiGenetic – Transgenerational, inherited, non-DNA

• 3) Cultural: Diet deficiency or imbalance• 4) Other: Brown fat, telomere length

What can we do to prevent Metabolic Syndrome in about the South Asian population in Canada?

SAHARA Project

A multi-media based intervention aiming to provide culturally tailored health messaging and feedback to participants with the goal of reducing their cardiac risk score over a 6-month period.

http://www.youtube.com/watch?v=SwZdUSmWBpo

Screening Cohort• 320 Men and women of South Asian ancestry • Permanent residents of Ontario/BC• ≥30 years• Access to email, cell phone with text messaging

capability, or a smart phone• No previous MI, CABG, Stroke

Study Outcomes

• Primary outcome: change in IHRS after 1 year• Secondary outcomes:

• Change in components of risk score - blood pressure, HbA1c, waist to hip ratio, and apolipoproteins B and A

• Difference in clinical events between the intervention and control groups at the end of the study

• Rate of change in IHRS over time

INTERHEART Modifiable Risk Score Report

Genetic Risk Score Report

Community or Contextual Factors and Future Interventions

Social Networks

• 12,000 people tracked for 32 yrs• Social networks play a powerful role in

determining weight gain• If spouse or brother is overweight –1.40x

would be overweight• Friends had the most powerful influence 1.5-

2.0x - “kind of social contagion” • Think about typical S. Asian social networks-

centered around eating, not around moving• Older cultural beliefs must change to prevent

weight gain

Kristakis NEJM 2007

Social Networks 2008; 30: 330-342.

Obesity in a Facebook Network

Population & high risk individualized strategy for the Prevention of CVD

GOAL

Type of Strategy

Examples

Determinants of Risk Behaviours in a

Population

Interventions with a Socio-Economic &

Political Focus

• Taxing Tobacco

• Subsidizing healthy foods

• Health Education

• Promote Physical Activity

Individuals with Risk Factors for

CVD

Interventions with a

Preventive Focus

• Identifying & treating individuals with high cholesterol or hypertension

• Smoking cessation in a smoker

Individuals with Manifest CVD

Interventions with a Clinical

Focus

• Lipid Lowering• Aspirin• Beta blockers• ACE-inhibitors• Appropriate revascularization

October 30, 2008

A PolyPill for all?

Aspirin

Statin

Thiazide

BB

ACE - I