Denver Garden Environment and Microbiome Study Disease (DGEM)

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.

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.

Diet Modification, Physical Activity, Weight Gain, Chronic Disease, Lifestyle, Sedentary, Health Behavior

Pilot Randomized Controlled Trial, Community Garden, Health Behavior Change, Physical Activity, Diet, Obesity, Neighborhood, Microbiome, Inflammatory biomarkers

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.

The non-gardening group will remain on the DUG wait lists and will not receive the 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: A garden plot in a Denver Urban Garden Seeds and plant starts Introductory gardening workshop 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.

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