Assessing health impacts of home food gardens with Wind River Indian Reservation families: protocol for a randomised controlled trial

INTRODUCTION: This community-based participatory research, Growing Resilience, will be the first full-scale randomised controlled trial we have identified that is designed to evaluate impacts of home gardening on family health. It is based on observational studies suggesting home food gardening has myriad health benefits, Wind River Indian Reservation (WRIR) families’ interest in home gardening and the need to end Native American health disparities with empowering, appropriate and effective health interventions. METHODS AND ANALYSIS: A total of 100 Native American families in WRIR who have not gardened recently but want to garden will be randomly allocated (1:1) to intervention (receiving 2 years of support designing, installing and maintaining a home food garden of at least 80 square feet (approximately 7 square meters) or to delayed-intervention control (receiving same gardening support after 2 years of data collection). Willing family members aged 5 and up will participate in data collection each February and August for 2 years, with blood, biometric and survey measures at each. The primary outcome is adult body mass index (BMI). Secondary outcomes include child BMI, and adult hand strength, self-reported physical and mental health, diabetes control and food security. Primary analysis will be intention to treat (ITT), using univariate and bivariate descriptive statistics followed by a mixed model to estimate the ITT effect of the intervention using analysis of covariance (ANCOVA) estimation. We will also examine treatment affects using a gardening fidelity measure, combined adult and child BMI outcomes using a lambda mu and sigma (LMS) Z-score reference data set and possible mechanisms of health impacts. ETHICS AND DISSEMINATION: This protocol was approved by the University of Wyoming Institutional Review Board (IRB) and the project’s Community Advisory Board. De-identified data will be shared with each tribe, and results will be published in peer-reviewed journals, summarised for distribution in WRIR, and shared at a national event to be hosted in WRIR in 2020. TRIAL REGISTRATION NUMBER: NCT02672748; Pre-results.