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Zinc Supplements in Lowering Cadmium Levels in Smokers

This study has been completed.
National Cancer Institute (NCI)
Information provided by (Responsible Party):
Wake Forest University Health Sciences Identifier:
First received: September 13, 2006
Last updated: January 18, 2017
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: No masking
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 Wake Forest University Health Sciences:

Primary Outcome Measures:
  • 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 ]

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   (Adult, Senior)
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
  Contacts and Locations
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Please refer to this study by its identifier: NCT00376987

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)
Principal Investigator: Gary G. Schwartz, MD, PhD, MPH Wake Forest University Health Sciences
  More Information

Responsible Party: Wake Forest University Health Sciences Identifier: NCT00376987     History of Changes
Other Study ID Numbers: CDR0000495325
Study First Received: September 13, 2006
Last Updated: January 18, 2017

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:
Lung Neoplasms
Pancreatic Neoplasms
Stomach Neoplasms
Head and Neck Neoplasms
Uterine Cervical Neoplasms
Urinary Bladder Neoplasms
Esophageal Neoplasms
Liver Neoplasms
Kidney 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
Uterine Neoplasms
Genital Neoplasms, Female
Urogenital Neoplasms
Uterine Cervical Diseases
Uterine Diseases
Genital Diseases, Female processed this record on April 28, 2017