Effects of indoor biophilic environments on cognitive function in elderly patients with diabetes: study protocol for a randomized controlled trial

Background: The prevalence of cognitive impairment in elderly diabetic patients is increasing, highlighting the importance of exploring strategies to prevent and ameliorate cognitive impairment in this population. Previous studies have focused mostly on improving cognition in elderly diabetic patients through three methods: medication, cognitive training, and lifestyle intervention. However, few studies have investigated the role of indoor biophilic environments in improving cognition. Biophilic environments improve human health by integrating natural elements into indoor architectural settings and have demonstrated efficacy in reducing stress and improving cognition. Therefore, it is worth exploring the effects of indoor biophilic environments on cognition in elderly diabetic patients. This study aims to investigate the effects of indoor biophilic environments on cognition in elderly diabetic patients, and the potential mechanisms. Methods: This is a single-center, randomized controlled trial, which includes a short-term VR intervention and a long-term real environment intervention. In the short-term intervention trial, 64 diabetic patients over 60 years old are randomly assigned to 1 of 7 intervention groups or a control group. All intervention groups are constructed by single or various combinations of the 3 indoor biophilic elements: natural decorative paintings, indoor potted plants, and ornamental fish. The primary outcome of the short-term intervention trial is the cognitive scores assessed by DSST and BDS. In the long-term intervention trial, 240 diabetic patients over 60 years old will be randomly assigned to either the intervention group or the control group. The biophilic elements in long-term intervention will be determined based on the results of the short-term VR intervention trial. The primary outcomes of the long-term intervention trial are cognitive scores measured by DSST and MoCA, as well as concentrations of plasma p-tau181, esRAGE, and IL-6. Conclusion: The findings will be utilized to develop a restorative living environment for elderly patients with diabetes to improve cognition. Clinical trial registration: https://www.chictr.org.cn, identifier [ChiCTR2300072329].