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

This study has been completed.
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)
ClinicalTrials.gov Identifier:
First received: February 27, 2002
Last updated: January 18, 2008
Last verified: January 2008
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.

Diabetes Mellitus, Non-Insulin Dependent
Cardiovascular Diseases
Myocardial Infarction
Heart Diseases
Diabetes Mellitus

Study Type: Observational

Further study details as provided by National Heart, Lung, and Blood Institute (NHLBI):

Study Start Date: September 2001
Study Completion Date: August 2007
Primary Completion Date: August 2007 (Final data collection date for primary outcome measure)
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.


Genders Eligible for Study:   Both
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.
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Please refer to this study by its ClinicalTrials.gov identifier: NCT00031213

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

No publications provided

ClinicalTrials.gov Identifier: NCT00031213     History of Changes
Other Study ID Numbers: 992 
Study First Received: February 27, 2002
Last Updated: January 18, 2008
Health Authority: United States: Federal Government

Additional relevant MeSH terms:
Cardiovascular Diseases
Diabetes Mellitus
Diabetes Mellitus, Type 2
Myocardial Infarction
Endocrine System Diseases
Glucose Metabolism Disorders
Heart Diseases
Metabolic Diseases
Myocardial Ischemia
Vascular Diseases

ClinicalTrials.gov processed this record on February 11, 2016