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Coffee and Metabolic Health Outcomes (COMETH)

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: NCT01738399
Recruitment Status : Completed
First Posted : November 30, 2012
Last Update Posted : April 23, 2015
Information provided by (Responsible Party):
National University Hospital, Singapore

Brief Summary:
The purpose of the study is to investigate the long-term (24 weeks) effects of coffee consumption on insulin sensitivity in insulin resistant individuals.

Condition or disease Intervention/treatment Phase
Insulin Resistance Dietary Supplement: Coffee Dietary Supplement: Placebo Not Applicable

Detailed Description:
Coffee is a major source of the phenolic acid chlorogenic acid and a substantial source of trigonelline, niacin, lignans magnesium, and potassium. Several of these compounds have been shown to improve glucose metabolism in animal models. Consumption of coffee was inversely associated with the risk of type-2 diabetes in prospective cohort studies across the world. Consumption of 3 to 4 cups of coffee per day was associated with an approximately 25% lower risk of type-2 diabetes. However, direct evidence of the efficacy of coffee to reduce blood glucose and insulin resistance parameters in humans from randomized trials is still lacking. In recent small trials of short duration (up to 6 weeks) coffee consumption increased levels of the insulin-sensitizing hormone adiponectin, but did not significantly improve insulin sensitivity These results suggest that a larger longer-term trial of the effects of coffee consumption on directly measured insulin sensitivity is warranted.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 128 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: Influence of Coffee Consumption on Insulin Sensitivity in Overweight and Insulin Resistant Subjects.
Study Start Date : April 2012
Actual Primary Completion Date : December 2014
Actual Study Completion Date : December 2014

Arm Intervention/treatment
Experimental: Coffee
Subjects take 4 cups of coffee mix per day for 24 weeks
Dietary Supplement: Coffee
Placebo Comparator: Placebo
Subjects take 4 cups of placebo per day for 24 weeks
Dietary Supplement: Placebo

Primary Outcome Measures :
  1. Change in insulin sensitivity when compared to baseline as measured using the euglycemic hyperinsulinemic clamp. [ Time Frame: Baseline and 24 weeks ]

Secondary Outcome Measures :
  1. Change in fasting plasma glucose concentration from baseline to 12 weeks [ Time Frame: Baseline, 12 weeks ]
  2. Change in fasting plasma glucose concentration from baseline to 24 weeks [ Time Frame: Baseline, 24 weeks ]
  3. Change in fasting plasma total adiponectin concentrations from baseline to 12 weeks [ Time Frame: Baseline, 12 weeks ]
  4. Change in fasting plasma total adiponectin concentrations from baseline to 24 weeks [ Time Frame: Baseline, 24 weeks ]

Information from the National Library of Medicine

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Ages Eligible for Study:   35 Years to 69 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Subjects classified as being insulin-resistant in the screening visit. Subjects should have a non-diabetic fasting plasma glucose concentration (< 7.0 mM) and a HOMA-IR > 2.2. The HOMA-IR was demonstrated as a reliable indicator of insulin resistance strongly correlated with values obtained by clamp (4). The cut-off value of the HOMA-IR was defined according to data obtained in the Singapore cohort. It corresponds to the 75th percentile of the population. The HOMA-IR cut-off was subsequently revised to ≥ 1.3 to increase recruitment rates.
  • Age: ≥ 35 to ≤ 69 years old
  • Body mass index : ≥ 22.5 to ≤ 35.4 kg/m2
  • Users of at least 1 cups of caffeinated coffee per day who are willing to be randomized to any of the interventions.
  • Subjects should be willing to stop consuming caffeinated soft drinks or supplements during the study and to drink coffee with non-dairy creamer.
  • Non-smokers (< 1 cigarette per week)
  • Participants have been weight stable for at least -8 weeks pre-ceding the screening visit (± 2.5 kgs).
  • Chinese, Malay and Indian ethnicity

Exclusion Criteria:

Subjects representing one or more of the following criteria are excluded from participation in the study:

  • Any condition/illness that may affect the study outcomes or would make participation potentially harmful such as pregnancy or breastfeeding, diabetes mellitus, heart disease, stroke, hypertension, malabsorption syndromes, GERD, a history of ulcer, clotting or bleeding disorders,allergy to the test beverage, allergy to insulin, according to a detailed medical history.
  • Participants who are allergic to foods may be excluded based on the investigator's discretion.
  • Participants consume > 2 alcoholic servings/day on a regular basis and > 8 caffeinated servings (based on tea and coffee)/day
  • Present drug abuse or use of medications that could interfere with the treatment including bronchodilators, quinolone antibiotics, monoamine oxidase inhibitors, anxiolytics, ranitidine, corticosteroids, growth hormone, anti-hypertensives. These conditions will be screened based on subject reporting. Participants will be asked to bring in their current medications at the time of screening, and these will be checked by the study-staff.
  • Subject is taking traditional medications, herbal or dietary supplements that may affect the study outcome in the opinion of the investigators.
  • Subject who cannot be expected to comply with the study procedures in the opinion of the investigators.
  • Currently participating or having participated in another clinical trial during the last 12 weeks prior to the beginning of this study.
  • Premenopausal women with self-reported irregular menstrual cycles or peri-menopausal women (participants who stopped getting their menses for less than 48 weeks ).

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01738399

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Saw Swee Hock School of Public Health
Singapore, Singapore, 117597
Sponsors and Collaborators
National University Hospital, Singapore
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Principal Investigator: Rob M van Dam Saw Swee Hock School of Public Health, National University of Singapore

Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: National University Hospital, Singapore Identifier: NCT01738399    
Other Study ID Numbers: 11.09.NRC
First Posted: November 30, 2012    Key Record Dates
Last Update Posted: April 23, 2015
Last Verified: March 2012
Keywords provided by National University Hospital, Singapore:
Insulin resistance
Glucose metabolism
Additional relevant MeSH terms:
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Insulin Resistance
Glucose Metabolism Disorders
Metabolic Diseases
Hypoglycemic Agents
Physiological Effects of Drugs