Denver Garden Environment and Microbiome Study Disease (DGEM)

May 4, 2021 updated by: Jill Litt, University of Colorado, Boulder

A Pilot Randomized Controlled Trial of Gardening as an Intervention to Reduce Risk of Cancer and Heart

An interdisciplinary team with extensive garden study experience conducted a pilot randomized controlled clinical trial to see whether gardening reduced risk factors for diseases like cancer and heart disease. The pilot trial will provide preliminary data on associations between human microbiome, diet, physical activity, and social interactions and the outcomes of weight status and key inflammatory biomarkers.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The pilot study will lead to development of a future, large randomized controlled clinical trial, by fulfilling the following aims:

Pilot Aim 1: Demonstrate feasibility of recruitment and ability to perform study procedures.

Pilot Aim 2: Demonstrate the ability to measure accurately chronic disease risk factors such as diet, physical activity, weight gain, microbiome characteristics and inflammatory biomarkers.

Pilot Aim 3: Provide preliminary results on the efficacy of gardens as a preventive intervention, and estimates for a detailed power analysis for the proposed subsequent larger trial.

Aim 3a: Demonstrate that compared to non-gardeners, gardeners have 1) greater intake of fruits and vegetables; 2) better Healthy Eating Index (HEI); 3) lower Diet Inflammatory Index (DII); 4) reduced sedentary time and increased moderate-to-vigorous physical activity (MVPA); and reduced age-associated weight gain.

Aim 3b: For gardeners and non-gardeners, sample garden soil, gut, skin, and oral microbiome at six time points from April through September to characterize and compare bacterial load, pathogenic taxa, taxonomic diversity, relative dominance, indicator taxa, and metabolomic results.

Aim 3c: Demonstrate that gardening reduces inflammatory biomarkers linked to heart disease and cancer, including CRP, IL1b, IL4, IL6, IL10, and TNFa, and that the effect of gardening is mediated by diet, weight gain, physical activity and characteristics of the microbiome.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
16

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

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

  • United States
    • Colorado
      • Boulder, Colorado, United States, 80303
        • University of Colorado Boulder

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Able to give informed consent in English or Spanish
  • Aged 18 or over
  • Currently on the wait list for a new garden
  • Not have gardened in the past 2 gardening seasons

Exclusion Criteria:

  • Is not able to complete the study requirements in Spanish or English
  • Aged 17 or younger
  • Has gardened in the past 2 gardening seasons

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: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Community Garden Intervention Group
Participants randomized to the Community Garden Intervention Group will receive the garden intervention. Participants will be assigned a plot for one season and will receive a standard package of services and amenities to support participation in the community garden, including seeds and transplants, tools, new garden classes and access to master community gardeners in Denver.
Behavioral: Community Garden Intervention

The investigators will recruit 30 prospective gardeners who have not been gardening for the past two years and who are listed on Denver Urban Gardens (DUG) wait lists. DUG randomly assigns people on each garden wait list to available plots, using a lottery. This creates a natural randomized experiment. Participants randomized to the garden intervention will receive a standardized garden resource package, which includes the following:

  1. A garden plot in a Denver Urban Garden
  2. Seeds and plant starts
  3. Introductory gardening workshop
  4. Social events including garden-specific events and garden mentoring.

The non-gardening group will remain on the DUG wait lists and will not receive these resources.

Duration of the intervention is 1 year.
No Intervention: Wait List Control Group
The non-gardening group will remain on the DUG wait lists and will not receive the garden intervention.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in fruit and vegetable intake from baseline at 20 weeks
Time Frame: Measurements will occur during weeks 1-2 (3 random recalls) and weeks 18-20 (3 random recalls)
6 24-hour diet recalls will be collected at random
Measurements will occur during weeks 1-2 (3 random recalls) and weeks 18-20 (3 random recalls)
Change in sedentary time behavior from baseline at 20 weeks
Time Frame: 2 measurements over 6 months, T1 (Week 1) and T6 (Week 20)
Accelerometers will be adhered to thigh and collect data for 7 days
2 measurements over 6 months, T1 (Week 1) and T6 (Week 20)
Change in bacterial load from baseline at 20 weeks
Time Frame: Every 3-4 weeks up to 20 weeks (Week 1, Week 4, Week 7, Week 10, Week 14, Week 18)
Microbiome data will be collected six time points using 1 gut, 2 skin, and 1 oral samples
Every 3-4 weeks up to 20 weeks (Week 1, Week 4, Week 7, Week 10, Week 14, Week 18)
Change in moderate-to-vigorous physical activity (MVPA) from baseline at 20 weeks
Time Frame: 2 measurements over 6 months, T1 (Week 1) and T6 (Week 20)
Accelerometers will be adhered to thigh and collect data for 7 days
2 measurements over 6 months, T1 (Week 1) and T6 (Week 20)
Change in weight (kg) from baseline at 20 weeks
Time Frame: 2 measurements over 6 months, T1 (Week 1) and T6 (Week 20)
Objective measurements of weight will be collected
2 measurements over 6 months, T1 (Week 1) and T6 (Week 20)
Change in waist circumference from baseline at 20 weeks
Time Frame: 2 measurements over 6 months, T1 (Week 1) and T6 (Week 20)
Objective measurement of waist circumference
2 measurements over 6 months, T1 (Week 1) and T6 (Week 20)
Change in pathogenic taxa from baseline at 20 weeks
Time Frame: Every 3-4 weeks up to 20 weeks (Week 1, Week 4, Week 7, Week 10, Week 14, Week 18)
Microbiome data will be derived from 1 gut, 2 skin, and 1 oral samples
Every 3-4 weeks up to 20 weeks (Week 1, Week 4, Week 7, Week 10, Week 14, Week 18)
Change in taxonomic diversity from baseline at 20 weeks
Time Frame: Every 3-4 weeks up to 20 weeks (Week 1, Week 4, Week 7, Week 10, Week 14, Week 18)
Microbiome data will be derived from 1 gut, 2 skin, and 1 oral samples
Every 3-4 weeks up to 20 weeks (Week 1, Week 4, Week 7, Week 10, Week 14, Week 18)
Change in relative dominance from baseline at 20 weeks
Time Frame: Every 3-4 weeks up to 20 weeks (Week 1, Week 4, Week 7, Week 10, Week 14, Week 18)
Microbiome data will be derived from 1 gut, 2 skin, and 1 oral samples
Every 3-4 weeks up to 20 weeks (Week 1, Week 4, Week 7, Week 10, Week 14, Week 18)
Change in indicator taxa from baseline at 20 weeks
Time Frame: Every 3-4 weeks up to 20 weeks (Week 1, Week 4, Week 7, Week 10, Week 14, Week 18)
Microbiome data will be derived from 1 gut, 2 skin, and 1 oral samples
Every 3-4 weeks up to 20 weeks (Week 1, Week 4, Week 7, Week 10, Week 14, Week 18)
Change in Inflammatory biomarkers from baseline at 20 weeks
Time Frame: 20 weeks
Samples include hs-CRP, TNF-alpha, IL1b, IL4, IL6, IL10
20 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in HbA1C from baseline at 20 weeks
Time Frame: 20 weeks
20 weeks
Change in blood pressure from baseline at 20 weeks
Time Frame: 20 weeks
20 weeks
Change in lipid profile from baseline at 20 weeks
Time Frame: 20 weeks
Including LDL, HDL, total cholesterol, triglycerides
20 weeks

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Colorado, Boulder

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Jill S Litt, PhD, University of Colorado, Boulder

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 2, 2016

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 15, 2017

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 30, 2017

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 17, 2017

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 17, 2017

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 24, 2017

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 7, 2021

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 4, 2021

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2021

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 16-0138, 16-0424

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

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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