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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

Brief Summary:

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.

Condition or disease Intervention/treatment Phase
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 Phase 2

Detailed Description:


  • 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.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 61 participants
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Prevention
Official Title: Do Dietary Supplements of Zinc Reduce Serum Cadmium Levels in Smokers?
Study Start Date : December 2003
Actual Primary Completion Date : October 2006
Actual Study Completion Date : June 2015

Intervention Details:
  • Dietary Supplement: zinc oxide
    Oral daily dietary supplement containing 80 mg Zinc oxide

Primary Outcome Measures :
  1. Reduction of cadmium levels [ Time Frame: 17 weeks ]
  2. Serum levels of cotinine, zinc, and cadmium at 3 pre-supplementation visits and at 6 supplementation visits [ Time Frame: 17 weeks ]
  3. Correlation of increased cadmium levels with decreased mismatch repair [ Time Frame: 17 weeks ]
  4. Reversal of cadmium-induced inhibition of mismatch repair [ Time Frame: 17 weeks ]

Information from the National Library of Medicine

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Ages Eligible for Study:   21 Years to 120 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No


  • 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

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): NCT00376987

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United States, North Carolina
Wake Forest University Comprehensive Cancer Center
Winston-Salem, North Carolina, United States, 27157-1096
Sponsors and Collaborators
Wake Forest University Health Sciences
National Cancer Institute (NCI)
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Principal Investigator: Gary G. Schwartz, MD, PhD, MPH Wake Forest University Health Sciences
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Responsible Party: Wake Forest University Health Sciences Identifier: NCT00376987    
Other Study ID Numbers: CDR0000495325
First Posted: September 15, 2006    Key Record Dates
Last Update Posted: May 30, 2017
Last Verified: September 2015

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Studies a U.S. FDA-regulated Drug Product: Yes
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Wake Forest University Health Sciences:
renal cell carcinoma
bladder cancer
cervical cancer
esophageal cancer
gastric cancer
adult acute myeloid leukemia
pancreatic cancer
hypopharyngeal cancer
lip and oral cavity cancer
laryngeal cancer
nasopharyngeal cancer
oropharyngeal cancer
paranasal sinus and nasal cavity cancer
non-small cell lung cancer
small cell lung cancer
adult primary liver cancer
tongue cancer
tobacco use disorder
Additional relevant MeSH terms:
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Lung Neoplasms
Pancreatic Neoplasms
Stomach Neoplasms
Uterine Cervical Neoplasms
Urinary Bladder Neoplasms
Esophageal Neoplasms
Liver Neoplasms
Tobacco Use Disorder
Respiratory Tract Neoplasms
Thoracic Neoplasms
Neoplasms by Site
Lung Diseases
Respiratory Tract Diseases
Digestive System Neoplasms
Endocrine Gland Neoplasms
Digestive System Diseases
Pancreatic Diseases
Endocrine System Diseases
Gastrointestinal Neoplasms
Gastrointestinal Diseases
Stomach Diseases
Head and Neck Neoplasms
Uterine Neoplasms
Genital Neoplasms, Female
Urogenital Neoplasms
Uterine Cervical Diseases
Uterine Diseases
Urologic Neoplasms
Urinary Bladder Diseases