Zinc Supplements in Lowering Cadmium Levels in Smokers

This study has been completed.
National Cancer Institute (NCI)
Information provided by (Responsible Party):
Comprehensive Cancer Center of Wake Forest University
ClinicalTrials.gov Identifier:
First received: September 13, 2006
Last updated: September 30, 2015
Last verified: September 2015

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 Intervention Phase
Bladder Cancer
Cervical Cancer
Esophageal Cancer
Gastric Cancer
Head and Neck Cancer
Kidney Cancer
Liver Cancer
Lung Cancer
Pancreatic Cancer
Tobacco Use Disorder
Dietary Supplement: zinc oxide
Phase 2

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Prevention
Official Title: Do Dietary Supplements of Zinc Reduce Serum Cadmium Levels in Smokers?

Resource links provided by NLM:

Further study details as provided by Comprehensive Cancer Center of Wake Forest University:

Primary Outcome Measures:
  • Reduction of cadmium levels [ Time Frame: 17 weeks ] [ Designated as safety issue: No ]
  • Serum levels of cotinine, zinc, and cadmium at 3 pre-supplementation visits and at 6 supplementation visits [ Time Frame: 17 weeks ] [ Designated as safety issue: No ]
  • Correlation of increased cadmium levels with decreased mismatch repair [ Time Frame: 17 weeks ] [ Designated as safety issue: No ]
  • Reversal of cadmium-induced inhibition of mismatch repair [ Time Frame: 17 weeks ] [ Designated as safety issue: No ]

Enrollment: 61
Study Start Date: December 2003
Study Completion Date: June 2015
Primary Completion Date: October 2006 (Final data collection date for primary outcome measure)
Intervention Details:
    Dietary Supplement: zinc oxide
    Oral daily dietary supplement containing 80 mg Zinc oxide
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.


Ages Eligible for Study:   21 Years to 120 Years
Genders Eligible for Study:   Both
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
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT00376987

United States, North Carolina
Wake Forest University Comprehensive Cancer Center
Winston-Salem, North Carolina, United States, 27157-1096
Sponsors and Collaborators
Comprehensive Cancer Center of Wake Forest University
National Cancer Institute (NCI)
Principal Investigator: Gary G. Schwartz, MD, PhD, MPH Comprehensive Cancer Center of Wake Forest University
  More Information

Responsible Party: Comprehensive Cancer Center of Wake Forest University
ClinicalTrials.gov Identifier: NCT00376987     History of Changes
Other Study ID Numbers: CDR0000495325  CCCWFU-98903  CCCWFU-BG03-538 
Study First Received: September 13, 2006
Last Updated: September 30, 2015
Health Authority: United States: Institutional Review Board

Keywords provided by Comprehensive Cancer Center of Wake Forest University:
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:
Esophageal Neoplasms
Head and Neck Neoplasms
Liver Neoplasms
Pancreatic Neoplasms
Stomach Neoplasms
Tobacco Use Disorder
Urinary Bladder Neoplasms
Uterine Cervical Neoplasms
Chemically-Induced Disorders
Digestive System Diseases
Digestive System Neoplasms
Endocrine Gland Neoplasms
Endocrine System Diseases
Esophageal Diseases
Gastrointestinal Diseases
Gastrointestinal Neoplasms
Genital Diseases, Female
Genital Neoplasms, Female
Liver Diseases
Mental Disorders
Neoplasms by Site
Pancreatic Diseases
Stomach Diseases
Substance-Related Disorders
Urinary Bladder Diseases
Urogenital Neoplasms
Urologic Diseases
Urologic Neoplasms
Uterine Cervical Diseases

ClinicalTrials.gov processed this record on May 30, 2016