Niacin, N-3 Fatty Acids and Insulin Resistance

September 28, 2021 updated by: William S. Harris, PhD, FAHA, FNLA, University of South Dakota
This research study is being conducted to test the effects of two drugs on blood lipids (cholesterol and triglycerides) and blood sugar (glucose) levels in patients with diabetes or "pre-diabetes" (both of which have a condition called "insulin-resistance"). These products are Niaspan (extended release nicotinic acid) and Omacor (omega-3 acid ethyl esters). We hypothesize that the combination of Niaspan and Omacor will reduce serum triglyceride levels, increase HDL-cholesterol levels and do so without altering glucose levels.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The insulin resistance syndrome (IRS) afflicts approximately 25% of the US adult population. Its principal components include some or all of the following: central obesity, elevated triglyceride levels, decreased high density lipoprotein cholesterol (HDL-C) levels, a preponderance of small, dense low density lipoprotein (LDL) particles, hyperglycemia, hypertension, and increased thrombotic tendency. Subjects with the IRS are at increased risk for type 2 diabetes and/or coronary heart disease (CHD). While lifestyle changes (diet and exercise) often improve many of the manifestations of the IRS, pharmacotherapy is often needed to normalize individual components.

In recent studies from our laboratory, niacin and fish oil (n-3 fatty acids, FA) used in combination in insulin resistant individuals led to an expected improved the lipid phenotype (reduced triglycerides, increased HDL-C, and fewer, small, dense LDL particles). What was not expected, however, was that an important marker of adipose tissue insulin resistance - meal-induced suppression of free fatty acid (FFA) flux - would be improved as well. Further, knowing that these agents (given as monotherapy) have been reported to worsen glycemia in diabetic subjects, we were surprised to find no significant deterioration in glycemic control. Further preliminary studies in patients with poorly-controlled type 2 diabetes confirmed the ability of this combination of over-the-counter natural agents to significantly improve the lipid profile without adverse effects on glycemia.

Our working hypothesis is that excessive FFA flux from adipose tissue raises serum triglyceride concentrations and leads to other manifestations of the IRS. FFA flux is chronically elevated in insulin resistant subjects due to the insensitivity (i.e., resistance) of their adipocytes to the anti-lipolytic effects of insulin. Released FFA (especially from visceral adipose depots) stimulate hepatic triglyceride synthesis, leading to elevated serum triglyceride levels which subsequently contribute to reduced HDL-C and increased small, dense LDL concentrations. In addition, a high FFA flux can interfere with whole body glucose disposal. If this hypothesis is true, then interventions that improve adipocyte insulin sensitivity may be expected to improve a spectrum of risk factors associated with the insulin resistant state.

Since our preliminary studies support this hypothesis, we propose the following four specific aims which will be tested in a 4-arm, randomized, placebo-controlled, double blind trial:

Specific Aim 1. To test the hypothesis that n-3 FA and niacin (given singly and in combination) will enhance insulin-mediated suppression of FFA rate of appearance (Ra; a surrogate for adipose tissue insulin sensitivity) in insulin resistant subjects.

Specific Aim 2. To test the hypothesis that n-3 FA and niacin (given singly and in combination) will improve insulin sensitivity in insulin resistant subjects.

Specific Aim 3. To test the hypothesis that n-3 FA and niacin (given singly and in combination) will reduce VLDL-triglyceride production rates in insulin resistant subjects.

Specific Aim 4. To test the hypothesis that n-3 FA and niacin (given singly and in combination) will improve the dyslipidemic profile (i.e., reduce serum triglyceride and small, dense LDL concentrations and elevate HDL-C concentrations) in insulin resistant subjects.

At the completion of these studies, we expect to have detailed information on the potential therapeutic efficacy and the kinetic mechanism of action of combined treatment with n-3 FA and niacin. A better understanding of the action of these agents should lead to a clearer appreciation of the relationship between FFA flux and insulin resistance, to more effective therapy for the dyslipidemia of insulin resistance and ultimately to reduced risk for CAD in this burgeoning patient population.

Study Type

Interventional

Enrollment (Actual)

68

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • South Dakota
      • Sioux Falls, South Dakota, United States, 57105
        • Sanford Clinic Clinical Research Services

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

40 years to 69 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

40 and 69 years of age Male or female (without hormonal cycling as described below) BMI > 25 Fasting serum triglycerides > 150 mg/dL Ratio of TG/HDL-C > 3.5

Exclusion Criteria:

BMIs > 40 kg/m2 TG > 750 mg/dL HDL-C < 10 mg/dL Presence of other secondary causes of dyslipidemia or hyperglycemia such as hepatic, renal, thyroid or other endocrine diseases History of hypersensitivity to niacin or fish oils History of gout, hepatitis, peptic ulcer or cardiovascular disease Presence of diabetes mellitus, whether controlled by diet or drugs. (We will eliminate subjects with undiagnosed diabetes by screening for fasting glucose > 126 mg/dL) Use of any dietary supplements providing more than 50 mg of niacin or 100 mg of n-3 FA Use of any herbal preparations or weight-loss products Taking any lipid-lowering drugs for at least four weeks prior to screening for the study Medically-required treatment with nitrates, calcium channel blockers, or adrenergic blocking agents (per the Niaspan package insert) Hemoglobin < 12 g/dL (owing to the significant amount of blood being drawn) LDL-C > 145 mg/dL. (This restriction will prevent the randomization of any subject whose LDL-C levels, if assigned to an n-3 FA group, might rise by 10% and thus exceed 160 mg/dL) Known substance abuse Participation in a clinical drug trial anytime during the 30 days prior to screening Anyone whom the investigators judge to be a poor candidate

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: 1
Dual placebo
Drug: placebo
omacor placebo plus niaspan placebo
Experimental: 2
niaspan
Drug: extended release niacin
2 g qpm
Other Names:
  • niaspan
Experimental: 3
lovaza
Drug: omega-3 acid ethyl esters
4 q qd
Other Names:
  • lovaza omacor
Drug: omega-3 acid ethyl esters
4 g qd
Other Names:
  • lovaza omacor
Experimental: 4
combined therapy
Drug: combined treatment
omega-3 acid ethyl esters 4 g qd and extended release niacin, titrate up to 2 g Qpm
Other Names:
  • niaspan
  • lovaza, omacor

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Serum TG
Time Frame: 4 months
Change From Baseline to 4 Months in Serum Triglycerides
4 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Non-HDL-C
Time Frame: baseline and 4 months
Change From Baseline to 4 Months in Serum Non-HDL cholesterol
baseline and 4 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of South Dakota

Collaborators

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Investigators

  • Principal Investigator: William S Harris, PhD, Sanford Research/USD

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

October 1, 2007

Primary Completion (Actual)

August 1, 2008

Study Completion (Actual)

December 1, 2008

Study Registration Dates

First Submitted

February 2, 2006

First Submitted That Met QC Criteria

February 2, 2006

First Posted (Estimate)

February 3, 2006

Study Record Updates

Last Update Posted (Actual)

October 26, 2021

Last Update Submitted That Met QC Criteria

September 28, 2021

Last Verified

September 1, 2021

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • DK61486 (completed)
  • R01DK061486 (U.S. NIH Grant/Contract)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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