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Zinc Supplements in Lowering Cadmium Levels in Smokers

This study is ongoing, but not recruiting participants.
Information provided by (Responsible Party):
Comprehensive Cancer Center of Wake Forest University Identifier:
First received: September 13, 2006
Last updated: September 29, 2014
Last verified: July 2013

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
Estimated Study Completion Date: November 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 and older
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
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: 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
Principal Investigator: Gary G. Schwartz, MD, PhD, MPH Comprehensive Cancer Center of Wake Forest University
  More Information

Additional Information:
No publications provided

Responsible Party: Comprehensive Cancer Center of Wake Forest University Identifier: NCT00376987     History of Changes
Other Study ID Numbers: CDR0000495325, CCCWFU-98903, CCCWFU-BG03-538
Study First Received: September 13, 2006
Last Updated: September 29, 2014
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
Pancreatic Neoplasms
Tobacco Use Disorder
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
Mental Disorders
Neoplasms by Site
Pancreatic Diseases
Substance-Related Disorders
Urogenital Neoplasms
Uterine Cervical Diseases
Uterine Diseases
Uterine Neoplasms processed this record on February 27, 2015