Recruiting

Observational Study

Sponsor:

University of South Florida

Code:

NCT07799402

Conditions

Mild Cognitive Impairment

Alzheimer Disease (AD)

Dementia

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Accepted

Study Details

Brief summary:

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.

Conditions

Mild Cognitive Impairment

Alzheimer Disease (AD)

Dementia

Study ID

NCT07799402

Start date

Sep 16, 2021

Status verified date

Aug, 2026

Completion date

Sep, 2031

Anticipated

Primary completion date

Sep, 2031

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Accepted

Inclusion Criteria:

Age 18-60 years for young healthy participants, or age 60 years and older for older adult participants.

Participants meeting one of the following cognitive categories:

Normal cognitive function Mild cognitive impairment (MCI) Alzheimer's disease or Alzheimer's disease-related dementia Able to participate in the informed consent process as applicable. For participants unable to provide informed consent because of cognitive impairment, consent may be obtained from a legally authorized representative (LAR) according to the approved protocol.

Exclusion Criteria:

History of brain or gastrointestinal surgery within the past 5 years. History of cancer and/or cancer treatment within the past 5 years, except non-melanoma skin cancer.

History of systemic cancer treatment within the past 5 years. Neurological disorders including epilepsy, Parkinson's disease, or amyotrophic lateral sclerosis.

Antibiotic use within the past 30 days. Diarrhea, vomiting, and/or food poisoning within the past 30 days. History of inflammatory bowel disease. Body mass index (BMI) greater than 45 kg/m² or less than 18 kg/m². Weight loss of more than 10 pounds within the past 2 weeks.

Study Design

Enrollment

700 participants

Anticipated

Interventions and Outcome Measures

Arms

Young Healthy Adults

Healthy adults aged 18-60 years with normal cognitive function. Participants undergo baseline assessments and annual follow-up for up to 5 years.

Cognitively Healthy Older Adults

Adults aged 60 years and older with normal cognitive function. Participants undergo baseline assessments and annual follow-up for up to 5 years.

Mild Cognitive Impairment (MCI)

Adults aged 60 years and older with mild cognitive impairment. Participants undergo baseline assessments and annual follow-up for up to 5 years.

Alzheimer's Disease/Dementia

Adults aged 60 years and older with Alzheimer's disease or Alzheimer's disease-related dementia. Participants undergo baseline assessment only and are not included in the 5-year longitudinal follow-up.

Primary outcome measure

  • Gut Microbiome Shannon Diversity Index [ Time Frame: Baseline for all participants and annually for up to 5 years for longitudinally followed participants ]

Central Contacts and Locations

Central contacts

Shalini Jain, PhD

813-974-8222jains10@usf.edu

Locations

Department of Neurosurgery and Brain and Spine and Faculty of USF Center for Microbiome Re-search, Microbiomes Institute

Recruiting

Tampa, Florida, United States, 33612

Contacts

Hariom Yadav, PhD

8139748222hyadav@usf.edu

Shalini Jain, PhD

jains10@usf.edu

More Information

Sponsor

University of South Florida

Last update posted

Sep 2, 2026

Last verified

Aug, 2026

Keywords

  • Gut microbiome
  • Oral microbiome
  • Cognitive impairment
  • Cognitive decline
  • Mild cognitive impairment
  • Alzheimer's disease
  • Dementia
  • Aging
  • Gut-brain axis
  • Intestinal permeability
  • Inflammation
  • Metabolomics
  • Microbiome diversity

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of South Florida on 2026-09-02.