Evaluating the Effects of Omega-3 Fatty Acids on Heart Disease and Behavior

Not Applicable

Completed

• Conditions: Inflammation; Cardiovascular Diseases; Mood Disorders
• Interventions: Dietary Supplement: Soybean Oil (Placebo); Dietary Supplement: Fish Oil

• Registration Number: NCT00663871
• Lead Sponsor: University of Pittsburgh

Brief Summary

Omega-3 fatty acids are a certain kind of fish fat that has recently been shown to have health benefits. This study will examine the effectiveness of fish oil supplementation for reducing the early signs of heart disease risk and for improving mood, impulsivity, and anger levels.

Detailed Description

Cardiovascular disease (CVD) is a broad term that includes diseases that affect the heart and blood vessels, including coronary heart disease, heart failure, high blood pressure, stroke and vascular dementia. CVD is the leading cause of death in the United States, resulting in 700,000 deaths each year. Preliminary research has shown that increased consumption of fish, specifically the omega-3 fatty acids found in fish oil, has beneficial effects in people with CVD. Fish oil may also have positive effects on the psychological health and well-being of people with psychiatric disorders. However, more research is needed to confirm the positive physical and psychological effects of fish oil in healthy adults. The purpose of this study is to explore potentail effects of fish oil supplementation on CVD mechanisms and risk markers, and on depressive symptoms, antagonistic disposition, and levels of impulsivity and aggression.

This study will enroll healthy adults who habitually consume low quantities of long-chain omega-3 fatty acids. Participants will be randomly assigned to receive either fish oil supplements or placebo on a daily basis for 4 months. Study visits will occur at baseline and Months 2 and 4. At the baseline and Month 4 visits, participants will undergo the following measures as primary study aims: blood collection for inflammatory markers; heart rate and variability measurements; and interviews, psychological tests, and questionnaires to assess mood, disposition, impulsivity, and aggression.

As secondary aims, we will test for any effects of fish oil on cognitive performance and, if a main effect on inflammatory markers is found, we will test for moderation by select genetic polymorphisms.

As an exploratory aim, we will test for any effects of fish oil on structural or functional brain imaging. (This exploratory aim was mistakenly listed as a secondary aim at the time of trial registration.)

Basic Information
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Recruitment & Eligibility
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Study & Design
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Trial Locations

Study Timeline

• Study First Submitted: 2008-04-18
• Study First Submitted QC: 2008-04-18
• Study First Posted: 2008-04-22
• Study Start: 2008-06
• Primary Completion: 2012-10
• Study Completion: 2012-10
• Results First Submitted: 2021-02-11
• Results First Submitted QC: 2021-04-19
• Status Verified: 2021-05
• Results First Posted: 2021-05-12
• Last Update Submitted: 2021-05-20
• Last Update Posted: 2021-06-11

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 272

Inclusion Criteria

• Currently employed at least 25 hours a week, but does not regularly work the third shift (i.e., night shift)
• English is primary language
• Consumes less than 300 mg/day of long-chain omega-3 fatty acids.

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Exclusion Criteria

• Serious allergy to fish (e.g., anaphylaxis, bronchospasm, serious skin reaction)
• History of atherosclerotic disease (e.g., myocardial infarction) or treatment of angina or claudication (e.g., angioplasty)
• Reported history of schizophrenia or bipolar disorder
• Long-term hepatitis
• Kidney failure
• Stroke or other neurological disorder
• Lung disease requiring drug treatment
• Stage 2 high blood pressure, defined as systolic blood pressure of 160 mm Hg or greater and diastolic blood pressure of 100 mm Hg or greater
• Alcohol consumption of more than five drinks per day each week (i.e., more than 35 alcoholic drinks each week)
• Pregnant or breastfeeding
• Currently taking any cardiovascular, psychotropic, glucocorticoid, lipid-lowering, insulin, or weight loss medications
• Currently taking fish oil supplements

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Placebo	Soybean Oil (Placebo)	Participants will take soybean oil (placebo) supplements daily for 4 months.
Fish Oil	Fish Oil	Participants will take fish oil supplements daily for 4 months.

Primary Outcome Measures

Name	Time	Method
Mean Successive Difference in Inter-beat Intervals Natural Log Transformed Paced Respiration	baseline and month 4	Mean successive difference in inter-beat intervals natural log transformed paced respiration in milliseconds
Type A, Total Score	baseline and month 4	Structured Interview - Type A Behavior Pattern using the Interpersonal Hostility Assessment Technique (IHAT). The minimum value is 0, and the maximum value is 12. A higher score suggests a worse outcome.
Total Power (0 to .40 Hz) Heart Rate Variability Natural Log Transformed Paced Respiration	baseline and month 4	Total power (0 to .40 Hz) heart rate variability natural log transformed paced respiration in Hertz (Hz) units.
C-reactive Protein (CRP)	baseline and month 4	fasting serum C-reactive protein (CRP) in milligrams per liter (mg/L)
Negative Affect	baseline and month 4	Negative affect questions adapted from the Positive and Negative Affect Schedule - Expanded Form administered via ecological momentary assessment. The minimum value is 1, and the maximum value is 6. A higher score are worse (more negative affect).
Hostility, Barefoot Score	baseline and month 4	The 27-item Barefoot Hostility Scale. The minimum value is 1, and the maximum value is 30. A higher score suggests a worse outcome.
Trait Anger	baseline and month 4	State-Trait Anger Expression Inventory. The minimum value is 10, and the maximum value is 40. A higher score suggests a worse outcome.
High Frequency (.12 to .40 Hz) Heart Rate Variability Natural Log Transformed Paced Respiration	baseline and month 4	High frequency (.12 to .40 Hz) heart rate variability natural log transformed paced respiration in Hertz units (Hz)
Impulsivity	baseline and month 4	Barratt Impulsiveness Scale. The minimum value is 34, and the maximum value is 120. A higher score suggests a worse outcome.
Anger Expression	baseline and month 4	State-Trait Anger Expression Inventory. The minimum value is 0, and the maximum value is 72. A higher score suggests a worse outcome.
Circulating Serum Interleukin-6 (IL-6)	Baseline and Month 4	Systemic inflammation: fasting serum Interleukin-6 (IL-6)
Aggression	baseline and month 4	Bus-Perry Aggression Questionnaire. The minimum value is 14, and the maximum value is 53. A higher score suggests a worse outcome.
Total Power (0 to .40 Hz) Heart Rate Variability Natural Log Transformed Unpaced Respiration	baseline and month 4	Total power (0 to .40 Hz) heart rate variability natural log transformed unpaced respiration in Hertz (Hz) units
Mean Successive Difference in Inter-beat Intervals Natural Log Transformed Unpaced Respiration	baseline and month 4	Mean successive difference in inter-beat intervals natural log transformed unpaced respiration in milliseconds (msec)
High Frequency (.12 to .40 Hz) Heart Rate Variability Natural Log Transformed Unpaced Respiration	baseline and month 4	High frequency (.12 to .40 Hz) heart rate variability natural log transformed unpaced respiration in Hertz (Hz) units

Secondary Outcome Measures

Name	Time	Method
Fluid Intelligence	Baseline and Month 4	This outcome was based upon matrix reasoning task raw score, block design task raw score and spatial span forward raw score. Performance scores on each task were converted into Z-scores, and then averaged across tasks. The Z-score indicates the number of standard deviations away from the mean. A Z-score of 0 is equal to the mean with negative numbers indicating values lower than the mean and positive values higher. Higher Z scores indicate higher function (better outcome). The analysis compared changes in Z-scores between the two treatment groups.
Executive Function	Baseline and Month 4	Executive function was comprised of trail making B - A time, digit span forward and digit span backward completions. Performance scores on each task were converted into Z-scores, and then averaged across tasks. The Z-score indicates the number of standard deviations away from the mean. A Z-score of 0 is equal to the mean with negative numbers indicating values lower than the mean and positive values higher. Higher Z scores indicate higher function (better outcome). The analysis compared changes in Z-scores between the two treatment groups.
Learning / Episodic Memory	Baseline and Month 4	Learning/episodic memory was comprised of d' from the four word memory task and the average performance across all trials of the Rey auditory verbal learning test. Performance scores on each task were converted into Z-scores, and then averaged across tasks. The Z-score indicates the number of standard deviations away from the mean. A Z-score of 0 is equal to the mean with negative numbers indicating values lower than the mean and positive values higher. Higher Z scores indicate higher function (better outcome). The analysis compared changes in Z-scores between the two treatment groups.
Psychomotor Speed	Baseline and Month 4	Psychomotor speed was comprised of trail making A time, Stroop word-only time and color-only time. Performance scores on each task were converted into Z-scores, and then averaged across tasks. The Z-score indicates the number of standard deviations away from the mean. A Z-score of 0 is equal to the mean with negative numbers indicating values lower than the mean and positive values higher. Higher Z scores indicate higher function (better outcome). The analysis compared changes in Z-scores between the two treatment groups.
Moderation of Effects of Fish Oil on Inflammatory Markers by Select Genetic Polymorphisms	Measured at Month 4	Circulating serum concentrations of IL6 and CRP before and after supplementation with fish oil or placebo.

Trial Locations

Locations (1)

University of Pittsburgh; 🇺🇸 Pittsburgh, Pennsylvania, United States