Microbiome in Aging Gut and Brain (MiaGB) Study

The Microbiome in Aging Gut and Brain (MiaGB) Study is an observational study designed to examine whether differences in the microorganisms living in the gut and mouth are associated with cognitive health and cognitive decline. The study includes young healthy adults, cognitively healthy older adults, older adults with mild cognitive impairment (MCI), and older adults with Alzheimer's disease or related dementia. At the baseline visit, participants complete assessments of medical history, cognitive function, physical function, and diet and provide biological samples that may include stool, saliva, oral swabs, blood, and urine. Researchers will study the gut and oral microbiome and related biological factors, including metabolites and markers of intestinal permeability and inflammation, to determine whether these measures differ according to cognitive status. Young healthy adults, cognitively healthy older adults, and participants with MCI will be followed annually for up to 5 years to evaluate changes in the microbiome and cognitive function over time. Participants with Alzheimer's disease or related dementia will participate in the baseline assessment only. No drug, treatment, or other research intervention is assigned as part of this study.