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.

Study Overview

Detailed Description

OBJECTIVES:

  • 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.

Study Type

Interventional

Enrollment (Actual)

61

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • North Carolina
      • Winston-Salem, North Carolina, United States, 27157-1096
        • Wake Forest University Comprehensive Cancer Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

21 years to 120 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

DISEASE CHARACTERISTICS:

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

PATIENT CHARACTERISTICS:

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

PRIOR CONCURRENT THERAPY:

  • At least 2 weeks since prior and no other concurrent vitamins and zinc supplements

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: PREVENTION
  • Allocation: NON_RANDOMIZED
  • Interventional Model: SINGLE_GROUP
  • Masking: NONE

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Reduction of cadmium levels
Time Frame: 17 weeks
17 weeks
Serum levels of cotinine, zinc, and cadmium at 3 pre-supplementation visits and at 6 supplementation visits
Time Frame: 17 weeks
17 weeks
Correlation of increased cadmium levels with decreased mismatch repair
Time Frame: 17 weeks
17 weeks
Reversal of cadmium-induced inhibition of mismatch repair
Time Frame: 17 weeks
17 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

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

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

December 1, 2003

Primary Completion (ACTUAL)

October 1, 2006

Study Completion (ACTUAL)

June 1, 2015

Study Registration Dates

First Submitted

September 13, 2006

First Submitted That Met QC Criteria

September 13, 2006

First Posted (ESTIMATE)

September 15, 2006

Study Record Updates

Last Update Posted (ACTUAL)

May 30, 2017

Last Update Submitted That Met QC Criteria

May 25, 2017

Last Verified

September 1, 2015

More Information

Terms related to this study

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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