Omega-3 Fatty Acid/Fish Intake and Brachial Artery Flow-Mediated Dilation

Jennifer S. Anderson, MD, PhD, MEdCardiology Fellow/Research Fellow

in the Multi-Ethnic Study of Atherosclerosis

Background

• Multiple studies have shown an inverse relationship between fish/omega-3 fatty acid consumption and cardiovascular events/death

• One potential mechanism includes omega-3 fatty acids’ impact on endothelial function

• Flow-mediated dilation (FMD) is a noninvasive surrogate for endothelial function

• Few studies have examined the relationship between dietary fish and FMD

Study Hypotheses

1. Consumption of non-fried fish foods rich in long-chain omega-3 fatty acids (eicosapentanoic acid (EPA), docosahexanoic acid (DHA)) will be positively associated with larger FMD across ethnic groups.

Omega-3 rich (EPA, DHA) diet Flow-mediated dilation (FMD)

2. Concentrations of EPA and DHA in plasma phospholipids will demonstrate positive associations with FMD.

• Cross-sectional analysis of MESA participants– n=6,814 men and women aged 45-85 years, free of CVD– Multi-center participation, 6 U.S. sites

• Baseline data collection including:– 120-item food frequency questionnaire– FMD measures (n = 3,137)– plasma phospholipid/fatty acid measures (n = 1,642)

Study Design

Exposure Measures: Dietary FishNon-fried fish tuna, salmon, sardines, sashimi or

sushi; other broiled, steamed, baked, or raw fish including trout, sole, halibut, poke, grouper

Shellfish (non-fried) shrimp, lobster, crab, oysters, mussels

Fish in mixed dishes(non-fried)

fish in enchiladas, burritos, quesadilla, pasta, stew, gumbo, paella, or salad

Fried fish fried fish or fish sandwich, fried shrimp, calamari

Exposure Measures: Plasma EPA and DHA

Outcome: Brachial Artery Measures

Baseline brachial artery diameterMaximum brachial artery diameter

• Multivariate linear regression• Stepwise approach• Final model included:

• Stratified by gender, race/ethnicity

Statistics

AgeGenderRace/ethnicitySmokingEducation

Income levelPhysical activitySystolic & diastolic BPLipid levelsBMI

Non-fried Fish & Brachial Measures: Overall Results, Baseline Artery Diameter

(n = 642) (n = 943) (n = 838) (n = 714)

Never/rare 1-3x/mo 1-2x/wk >2x/wk4.1

4.2

4.3

4.4

4.5

Unadjusted

Non-fried Fish Frequency

Base

line

diam

eter

, mm

*p < 0.001

Non-fried Fish & Brachial Measures: Baseline Diameter, Stratification by Gender*

Men Women

Never/rare 1-3x/mo 1-2x/wk >2x/wk3.8

3.9

4.0

4.1

4.2

Non-fried Fish Frequency

Never/rare 1-3x/mo 1-2x/wk >2x/wk4.6

4.7

4.8

4.9

5.0

Non-fried Fish Frequency

Base

line

diam

eter

, mm

*p = 0.02

(n = 338) (n = 455) (n = 411) (n = 344) (n = 304) (n = 488) (n = 427) (n = 370)

p = 0.10

*adjusted for age, race, BMI, smoking, diabetes, SBP, DBP, total:HDL, exercise, income, education, and HRT (women)

Non-fried Fish & Brachial Measures: FMD, Stratification by Gender*

Men Women

Test for gender-fish interaction significant (p = 0.008 and 0.05 for baseline diameter & FMD, respectively)

Never/rare 1-3x/mo 1-2x/wk >2x/wk3.5

3.7

3.9

4.1

4.3

4.5

4.7

4.9

Non-fried Fish Frequency(n = 304) (n = 488) (n = 427) (n = 370)(n = 338) (n = 455) (n = 411) (n = 344)

*p = 0.007

Never/rare 1-3x/mo 1-2x/wk >2x/wk3.5

3.7

3.9

4.1

4.3

4.5

4.7

4.9

Non-fried Fish Frequency

FMD,

% c

hang

e

p = 0.23

*adjusted for age, race, BMI, smoking, diabetes, SBP, DBP, total:HDL, exercise, income, education, and HRT (women)

Non-fried Fish & Brachial Measures: FMD, Stratification by Gender* & Race/Ethnicity

*results for women shown, fully adjusted model

white black chinese hispanic2

2.5

3

3.5

4

4.5

5

5.5

Never/rare 1-3x/mo 1x/wk ≥2x/wkNon-fried fish Frequency

FMD,

% ch

ange

*p = 0.02

Plasma EPA+DHA & Brachial Measures: FMD, Stratification by Gender*

1 2 3 43.5

3.7

3.9

4.1

4.3

4.5

4.7

4.9

Men

Quartile, plasma EPA+DHA%

FMD,

% ch

ange

p = 0.33

(n = 221) (n = 173) (n = 203) (n = 178)

*adjusted for age, race, BMI, smoking, diabetes, SBP, DBP, total:HDL, exercise, income, education, and HRT (women)

Plasma EPA+DHA & Brachial Measures: FMD, Stratification by Gender*

p = 0.33

(n = 221) (n = 173) (n = 203) (n = 178)

*adjusted for age, race, BMI, smoking, diabetes, SBP, DBP, total:HDL, exercise, income, education, and HRT (women)

Summary 1. Gender differences were observed in the

relationship between non-fried fish and both baseline artery diameter and FMD within the MESA cohort

2. Results examining plasma EPA+DHA levels corroborated results observed in dietary non-fried fish intake

3. Some race/ethnic differences were suggested

Next Steps

1. Are gender differences in brachial measures explained by variation in plasma %EPA vs %DHA?

2. Gender differences in the relationship between fish consumption & clinical events within MESA?

3. Gender differences in fish consumption & other markers of subclinical CVD (i.e. IMT, LV structure/function)?

4. Results replicable in other large cohorts with mixed race/ethnic groups?

Acknowledgements

Mentors & MESA coauthors:David Herrington, MD, MHS

Jennifer Nettleton, PhDDavid Siscovick, MD, MPH

Craig Johnson, MPHMichael Tsai, PhD

And special thanks to:Georgia Saylor

Thank You!

Questions?