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Heavy Metals, Obesity and Cardiovascular Risk - Ancillary to Look AHEAD

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: NCT00031213
Recruitment Status : Completed
First Posted : February 28, 2002
Last Update Posted : July 29, 2016
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)

Brief Summary:
To evaluate the relationship of baseline toenail chromium concentrations to weight loss, as well as the interaction between heavy metals and the beneficial effects of weight loss.

Condition or disease
Diabetes Mellitus, Non-insulin Dependent Cardiovascular Diseases Obesity Myocardial Infarction Heart Diseases Diabetes Mellitus

Detailed Description:


Heavy metals are a heterogeneous group of highly reactive substances, which may act as essential cofactors for physiologic processes and/or as toxic elements. Chromium, in particular, has been associated with obesity, diabetes, and weight loss. Other heavy metals have been associated with some of the consequences of obesity, including hypertension, hyperlipidemia, and cardiovascular disease. The Look AHEAD Study, a large randomized controlled trial of intensive lifestyle intervention for weight loss in obese patients with Type 2 diabetes mellitus, provides an excellent opportunity to address the impact of chromium on weight loss and diabetes control, as well as to assess the impact of other heavy metals on the physiologic consequences of weight loss.

The study is ancillary to the Look AHEAD clinical trial which is sponsored primarily by the National Institute of Diabetes and Digestive and Kidney Diseases and secondarily by the National Heart, Lung, and Blood Institute, the National Institute of Nursing Research, the Office of Research on Women's Health, the National Center on Minority Health and Health Disparities, and the Centers for Disease Control and Prevention. The Look AHEAD study is a multicenter, randomized clinical trial to examine the long-term effects of a lifestyle intervention designed to achieve and maintain weight loss in overweight diabetics.


This is an ancillary prospective observational study within the Look AHEAD trial. The ancillary study will collect toenail clippings from all participants (n = 5,000) at baseline and at the 1-year visit, and analyze a random subset of the toenails for their heavy metal content using instrumental neutron activation analysis. Toenails provide a time-integrated measure of heavy metal exposure, while instrumental neutron activation analysis provides the concentrations of about 50 heavy metals in the toenail samples, including chromium. This information will allow an evaluation of the relationship of baseline toenail chromium concentrations to weight loss, as well as the interaction between heavy metals and the beneficial effects of weight loss. The proposed study may provide, valuable insight into the determinants of the efficacy of weight loss interventions. In fact, the Look AHEAD trial, because of its size, may be one of the few studies in which these relationships can be measured reliably. In addition, the ancillary study will permit the setup of a specimen bank of toenails to be used in future case-cohort or nested case-control studies of the association of heavy metals with Look AHEAD endpoints, especially myocardial infarction and cardiovascular death.

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Study Type : Observational
Study Start Date : September 2001
Actual Primary Completion Date : August 2007
Actual Study Completion Date : August 2007

Information from the National Library of Medicine

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Ages Eligible for Study:   up to 100 Years   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
An estimated 5,000 obese diabetic subjects from the Look AHEAD clinical trial. There will be 2,500 women (50%) and 30% minorities.

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): NCT00031213

Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
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OverallOfficial: Eliseo Guallar Johns Hopkins University

Layout table for additonal information Identifier: NCT00031213    
Other Study ID Numbers: 992
R01HL070299 ( U.S. NIH Grant/Contract )
First Posted: February 28, 2002    Key Record Dates
Last Update Posted: July 29, 2016
Last Verified: January 2008
Additional relevant MeSH terms:
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Heart Diseases
Myocardial Infarction
Diabetes Mellitus
Diabetes Mellitus, Type 2
Cardiovascular Diseases
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases
Nutrition Disorders
Body Weight
Signs and Symptoms
Pathologic Processes
Myocardial Ischemia
Vascular Diseases