This site became the new on June 19th. Learn more.
Show more Menu IMPORTANT: Listing of a study on this site does not reflect endorsement by the National Institutes of Health. Talk with a trusted healthcare professional before volunteering for a study. Read more... Menu IMPORTANT: Talk with a trusted healthcare professional before volunteering for a study. Read more... Menu
Give us feedback

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) Identifier:
First received: February 27, 2002
Last updated: July 28, 2016
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 Obesity 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.


Ages Eligible for Study:   up to 100 Years   (Child, Adult, Senior)
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.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00031213

Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
OverallOfficial: Eliseo Guallar Johns Hopkins University
  More Information Identifier: NCT00031213     History of Changes
Other Study ID Numbers: 992
R01HL070299 ( U.S. NIH Grant/Contract )
Study First Received: February 27, 2002
Last Updated: July 28, 2016

Additional relevant MeSH terms:
Diabetes Mellitus
Cardiovascular Diseases
Heart Diseases
Myocardial Infarction
Diabetes Mellitus, Type 2
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases
Nutrition Disorders
Body Weight
Signs and Symptoms
Pathologic Processes
Myocardial Ischemia
Vascular Diseases processed this record on September 21, 2017