Niacin, N-3 Fatty Acids and Insulin Resistance

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00286234
Recruitment Status : Completed
First Posted : February 3, 2006
Last Update Posted : May 1, 2013
Information provided by:
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

February 2, 2006
February 3, 2006
May 1, 2013
October 2007
August 2008   (Final data collection date for primary outcome measure)
Serum TG and HDL-C [ Time Frame: baseline and 4 months ]
Not Provided
Complete list of historical versions of study NCT00286234 on Archive Site
Insulin sensitivity, postprandial triglyceridemia, peripheral arterial tonometry [ Time Frame: baseline and 4 months ]
Not Provided
Not Provided
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Niacin, N-3 Fatty Acids and Insulin Resistance
Niacin, N-3 Fatty Acids and Insulin Resistance
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.

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.

Phase 4
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
  • Metabolic Syndrome
  • Hypertriglyceridemia
  • Drug: omega-3 acid ethyl esters
    4 q qd
    Other Name: lovaza omacor
  • Drug: extended release niacin
    2 g qpm
    Other Name: niaspan
  • Drug: placebo
    omacor placebo plus niaspan placebo
  • Drug: omega-3 acid ethyl esters
    4 g qd
    Other Name: lovaza omacor
  • Drug: combined treatment
    omega-3 acid ethyl esters 4 g qd and extended release niacin, titrate up to 2 g Qpm
    Other Names:
    • lovaza, omacor
    • niaspan
  • Placebo Comparator: 1
    Dual placebo
    Intervention: Drug: placebo
  • Experimental: 2
    Intervention: Drug: extended release niacin
  • Experimental: 3
    • Drug: omega-3 acid ethyl esters
    • Drug: omega-3 acid ethyl esters
  • Experimental: 4
    combined therapy
    Intervention: Drug: combined treatment

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
December 2008
August 2008   (Final data collection date for primary outcome measure)

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

Sexes Eligible for Study: All
40 Years to 69 Years   (Adult, Older Adult)
Contact information is only displayed when the study is recruiting subjects
United States
DK61486 (completed)
Not Provided
Not Provided
William S. Harris, Sanford Research/USD
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Not Provided
Principal Investigator: William S Harris, PhD Sanford Research/USD
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
April 2013

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP