Zinc Supplements in Lowering Cadmium Levels in Smokers

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: NCT00376987
Recruitment Status : Completed
First Posted : September 15, 2006
Last Update Posted : May 30, 2017
National Cancer Institute (NCI)
Information provided by (Responsible Party):
Wake Forest University Health Sciences

September 13, 2006
September 15, 2006
May 30, 2017
December 2003
October 2006   (Final data collection date for primary outcome measure)
  • Reduction of cadmium levels [ Time Frame: 17 weeks ]
  • Serum levels of cotinine, zinc, and cadmium at 3 pre-supplementation visits and at 6 supplementation visits [ Time Frame: 17 weeks ]
  • Correlation of increased cadmium levels with decreased mismatch repair [ Time Frame: 17 weeks ]
  • Reversal of cadmium-induced inhibition of mismatch repair [ Time Frame: 17 weeks ]
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Complete list of historical versions of study NCT00376987 on Archive Site
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Zinc Supplements in Lowering Cadmium Levels in Smokers
Do Dietary Supplements of Zinc Reduce Serum Cadmium Levels in Smokers?

RATIONALE: Zinc supplements may lower cadmium levels in smokers and may help prevent DNA damage.

PURPOSE: This clinical trial is studying how well zinc supplements work in lowering cadmium levels in smokers.


  • Determine whether zinc supplements reduce cadmium levels in smokers.
  • Measure serum levels of cotinine (a biomarker of smoking), zinc (a marker of compliance), and cadmium (the dependent variable) at 3 pre-supplementation visits and at 6 supplementation visits.
  • Determine whether serum cadmium levels (adjusted for serum levels of cotinine) decrease during supplementation with VisiVite Smoker's Formula.
  • Determine if increased cadmium levels in the blood of cigarette smokers can be correlated with decreased mismatch repair.
  • Determine if administration of zinc-containing supplements reverses cadmium-induced inhibition of mismatch repair.

OUTLINE: This is an open-label, nonrandomized study.

Patients receive oral zinc supplements once daily for 12 weeks in the absence of unacceptable toxicity.

Blood, serum, and urine are collected once weekly for 3 weeks before beginning treatment and in weeks 5, 6, 9, 12, 15, and 17 for biomarker/laboratory analysis. Samples are examined for cadmium, zinc, and cotinine levels by atomic absorption spectrophotometry, expression of mismatch repair proteins (MSH2, MSH6, MSH3, MLH1, and PMS2), levels of messenger RNA by reverse transcriptase-polymerase chain reaction, and microsatellite instability by gel electrophoresis.

After completion of study therapy, patients are followed for 5 weeks.

Phase 2
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Prevention
  • Bladder Cancer
  • Cervical Cancer
  • Esophageal Cancer
  • Gastric Cancer
  • Head and Neck Cancer
  • Kidney Cancer
  • Leukemia
  • Liver Cancer
  • Lung Cancer
  • Pancreatic Cancer
  • Tobacco Use Disorder
Dietary Supplement: zinc oxide
Oral daily dietary supplement containing 80 mg Zinc oxide
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*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
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June 2015
October 2006   (Final data collection date for primary outcome measure)


  • Currently smoking ≥ 1 pack (20 cigarettes) per day
  • Baseline cadmium level ≥ 0.5 μg/L


  • Negative pregnancy test
  • Fertile patients must use effective contraception
  • No known gastrointestinal upset due to zinc vitamins or lozenges


  • At least 2 weeks since prior and no other concurrent vitamins and zinc supplements
Sexes Eligible for Study: All
21 Years to 120 Years   (Adult, Older Adult)
Contact information is only displayed when the study is recruiting subjects
United States
Studies a U.S. FDA-regulated Drug Product: Yes
Studies a U.S. FDA-regulated Device Product: No
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Wake Forest University Health Sciences
Wake Forest University Health Sciences
National Cancer Institute (NCI)
Principal Investigator: Gary G. Schwartz, MD, PhD, MPH Wake Forest University Health Sciences
Wake Forest University Health Sciences
September 2015

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