NCT05835037

Brief Summary

The purpose of this investigation is to evaluate the impact of zinc supplementation on fasting glucose levels, hemoglobin A1c (HbA1c), and other indices of glucose homeostasis in individuals with prediabetes. The investigators hypothesize that prediabetic subjects receiving zinc will demonstrate a greater decrease in HbA1c and blood glucose compared to prediabetic subjects receiving placebo. Specific Aim: Conduct a prospective, double-blind randomized clinical trial comparing the effects of 12 months of zinc supplementation (zinc gluconate 30 milligram \[mg\] per day) versus placebo on glucose homeostasis. Based upon expected effect size and power calculations, and anticipating a 20% drop-out rate, the investigators will study 200 prediabetic subjects (100 per group) using a 1:1 randomization design. HbA1c, fasting plasma glucose, and other measures will be obtained at 0, 6, and 12 months and will be compared between zinc supplementation and placebo groups.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
200

participants targeted

Target at P75+ for phase_4

Timeline
25mo left

Started Feb 2024

Longer than P75 for phase_4

Geographic Reach
1 country

1 active site

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

Study Progress52%
Feb 2024Jul 2028

First Submitted

Initial submission to the registry

April 17, 2023

Completed
11 days until next milestone

First Posted

Study publicly available on registry

April 28, 2023

Completed
10 months until next milestone

Study Start

First participant enrolled

February 16, 2024

Completed
4.4 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

July 1, 2028

Expected
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

July 1, 2028

Last Updated

May 5, 2026

Status Verified

April 1, 2026

Enrollment Period

4.4 years

First QC Date

April 17, 2023

Last Update Submit

April 28, 2026

Conditions

Outcome Measures

Primary Outcomes (2)

  • Zinc-dependent effect on fasting glucose levels at 1 year

    One of the investigator's primary endpoints will be to determine the difference in fasting glucose levels between zinc-treated and placebo-treated individuals after 1 year of receiving study drug

    1 year

  • Zinc-dependent effect on HbA1c at 1 year

    One of the investigator's primary endpoints will be to determine the difference in HbA1c levels between zinc-treated and placebo-treated individuals after 1 year of receiving study drug

    1 year

Secondary Outcomes (2)

  • Zinc-dependent effect on fasting glucose levels at 6 months

    6 months

  • Zinc-dependent effect on HbA1c at 6 months

    6 months

Study Arms (2)

Zinc treatment

EXPERIMENTAL

Research subjects administered zinc gluconate for 1 year (one 30 mg tablet per day)

Drug: Zinc Gluconate 30 MG

Placebo

PLACEBO COMPARATOR

Research subjects administered placebo for 1 year (1 tablet per day)

Drug: Placebo

Interventions

Participants will take one tablet per day (30 mg Zinc gluconate) for 1 year

Zinc treatment

Participants will take one placebo tablet per day for 1 year

Placebo

Eligibility Criteria

Age18 Years - 80 Years
Sexall
Healthy VolunteersNo
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Amish men or women who are 18 to 80 years old
  • Prediabetes (HgbA1c = 5.7-6.4% or fasting glucose levels 100-125 mg/dL)

You may not qualify if:

  • Pregnant
  • Currently breastfeeding
  • History of severe gastrointestinal disorders or upper gastrointestinal surgery
  • Has hemochromatosis, cancer, liver disease, kidney disease, cardiovascular disease, or other coexisting malignancy
  • Hemoglobin \< 12.5 g/dl (male) or \< 11 g/dl (female)
  • Severe hypertension (blood pressure \> 160/95 mm Hg)
  • Has a creatinine greater than 2.0 mg/dl, aspartate aminotransferase (AST) or alanine transaminase (ALT) greater than 2 times the upper limit of normal, hematocrit (Hct) less than 32%, or thyroid-stimulating hormone (TSH) less than 0.4 or greater than 5.5 milli-international units (mIU) per liter.
  • At the discretion of the study physician or PI, taking medications that affect the outcomes of the study including, but not limited to, corticosteroids, anti-psychotic agents, protease inhibitors, oral contraceptives, estrogens, niacin, and some classes of antidepressants, statins, and antihypertensive medications
  • Zinc hypersensitivity
  • Use of denture adhesive containing zinc
  • Taking other medications or zinc-containing supplements and is unwilling or cannot safely, in the opinion of the study physician, discontinue their use at least 2 weeks prior to protocol initiation
  • Any other condition that would, in the opinion of the investigator, place them at an unacceptable risk or render them unable to meet the requirements of the protocol.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Amish Research Clinic

Lancaster, Pennsylvania, 17602, United States

RECRUITING

MeSH Terms

Conditions

Prediabetic StateHyperglycemia

Interventions

gluconic acid

Condition Hierarchy (Ancestors)

Diabetes MellitusGlucose Metabolism DisordersMetabolic DiseasesNutritional and Metabolic DiseasesEndocrine System Diseases

Study Officials

  • Joshua P Lewis, PhD

    University of Maryland, Baltimore

    PRINCIPAL INVESTIGATOR

Central Study Contacts

Joshua P Lewis, PhD

CONTACT

Hilary B Whitlatch, MD

CONTACT

Study Design

Study Type
interventional
Phase
phase 4
Allocation
RANDOMIZED
Masking
DOUBLE
Who Masked
PARTICIPANT, CARE PROVIDER
Masking Details
Enrolled subjects will be randomized (1:1) to either the zinc or placebo intervention. Clinical staff and participants will be blinded to treatment assignment. Sealed, opaque assignment envelopes will be shuffled prior to study initiation and opened sequentially by a designated member of the research team who will then deliver the correct study drug to the clinical staff.
Purpose
BASIC SCIENCE
Intervention Model
PARALLEL
Model Details: Two hundred prediabetic individuals will be enrolled. The investigators will prospectively evaluate the impact of zinc supplementation on fasting glucose levels and HbA1c, through the completion of randomized, placebo-controlled study of zinc gluconate (one 30 mg tablet per day for 1 year) and placebo (1 tablet per day for 1 year). Participants will be randomized 1:1 to either zinc or placebo.
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Associate Professor of Medicine

Study Record Dates

First Submitted

April 17, 2023

First Posted

April 28, 2023

Study Start

February 16, 2024

Primary Completion (Estimated)

July 1, 2028

Study Completion (Estimated)

July 1, 2028

Last Updated

May 5, 2026

Record last verified: 2026-04

Data Sharing

IPD Sharing
Will share

It is possible that deidentified data will be deposited into large public databases as per NIH data sharing policies (e.g. database of Genotypes and Phenotype \[dbGAP\], Pharmacogenomics Knowledgebase \[PharmGKB\], etc.). Data to be shared would include, but not limited to, anthropometric data, study outcome data, and relevant covariate data used in statistical models. It is anticipated that data would be available after the completion of the trial. The data will be obtained from the participants and the study-related research procedures.

Shared Documents
STUDY PROTOCOL, SAP, ICF
Time Frame
In is anticipated that data would become available following the completion of the study and within 6 months of the publication of the primary analyses.
Access Criteria
To be determined

Locations