Discrimination and the Brain-Gut-Microbiome (BGM) Axis

Social Isolation and Discrimination as Stressors Influencing BGM Alterations

Obesity is a major public health problem related to a variety of illnesses such as heart disease and diabetes. Prior research indicates that social stressors contribute to risk for obesity, possibly through alterations in diet and physical activity. However, it is not fully clear how these alterations contribute to obesity. The purpose of this study is to examine how the stressors of social isolation and discrimination relate to eating behaviors and dietary patterns, and further, how these behaviors affect the brain-gut-microbiome (BGM) connections. This study will focus on Mexican and Filipina women because research shows that they encounter a high burden of obesity and exposure to social stressors. Approximately 300 Mexican and Filipina women will be screened and enrolled. They will then provide information about social stressors via food diaries, physical body measures (e.g. waist circumference), questionnaire data regarding diet and eating behaviors, and measures of physical activity. Stool and serum will be collected to analyze microbes and metabolomics, and MRI to assess brain changes in the reward network. Analytic techniques will be used to integrate data from these multiple data sources. This analysis will determine the unique differences associated with ethnicity and social stressors in moderating eating behaviors and dietary patterns. The results of this study will provide new information about a possible pathway whereby social stressors affect behavioral, neurological and microbiome mechanisms related to obesity risk and provide new information in BGM patterns in two understudied ethnic groups. In the long term, this research may suggest possible approaches for intervention that may help reduce inequalities in obesity and related health problems.

Study Overview

• Status: Recruiting
• Conditions: Stress; Discrimination, Racial; Social Isolation

• Study Type: Observational
• Enrollment (Anticipated): 270

Contacts and Locations

• Study Contact: Name: Allison Vaughan, MPH; Phone Number: 3108257206; Email: allisonvaughan@mednet.ucla.edu

Study Locations

• United States
  • California
    • Los Angeles, California, United States, 90095
      • Recruiting
      • University of California, Los Angeles
      • Contact: Allison Vaughan, MPH; Phone Number: 310-825-7206; Email: allisonvaughan@mednet.ucla.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 50 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

• Sampling Method: Non-Probability Sample

Study Population

Participants recruited from the greater Los Angeles Mexican & Filipina female population.

Description

Inclusion Criteria:

• Premenopausal females
• Ages 18-50
• Full Mexican or Filipino ancestry only
• BMI 19-40
• Fluent in English
• Right-handed

Exclusion Criteria:

Co-Morbidities including but not limited to:

• Type I diabetes (insulin dependent)
• Vascular disease
• Drastic weight loss (more than 10lbs over the preceding 2months)
• Frequent Strenuous exercise (i.e. marathon runners/heavy weight lifting)
• Abdominal surgeries including weight loss surgery, or partial/complete resection of the stomach or bowel
• Untreated thyroid disease
• Neurological disease
• Major medical condition that may put the subject at risk or interfere with data collection as determined by the PI/MD
• Chronic pain
• Diagnosed DSM IV active psychiatric illness including eating disorders. Must not be active or present for at least 2 years.
• Use of medications known to affect hunger, satiety, and/or appetite.
• Unable to safely participate in the MRI (claustrophobia, presence of devices affected by MRI such as pacemakers, neurostimulators, or any metallic foreign body, etc.)
• Pregnant, lactating, postpartum less than 6mo
• Women of childbearing age who are not practicing birth control or are planning to get pregnant during the study.
• Body weight at enrollment greater than 400lbs due to weight restrictions on the MRI table
• Use of oral/IV antibiotics within the last 3 months
• Use of probiotics in the last month
• Heavy use of tobacco, alcohol, and/or drug use/abuse
• Significant change in usual diet and/or weight loss of more than 10lbs in the last 2months
• Refugees or recent immigration of less than 2 years in the USA.
• Temporary workers/visitors/students
• Recent international travel if more than 3 weeks within the last 3 months.

Use of the following medications is exclusionary:

• Opiates/narcotics
• Chronic daily use of high dose OTC analgesics
• Anti-seizure medications
• Medications for appetite suppression
• Chronic use of laxatives/antidiarrheals, medications affecting GI motility
• Insulin
• Bile Acid Sequestrants
• Centrally acting medications that will interfere with the neuroimaging testing
• Thyroid replacement medications (OK if stable for at least 3mo)
• Heavy use of tobacco/cannabis
• Heavy use of alcohol ( >7/week for women)
• Antidepressants (5HT3's/Tricyclics) (OK if stable for at least 3mo)

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Mexican Women; Mexican, premenopausal women ages 18-50.
Filipina Women; Filipina, premenopausal women ages 18-50.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Multimodal Brain Signatures	Neuroimaging of participants brain via MRI procedure.	Measured once at Visit 2. Scan lasts about 1.5 hour.
Microbiome - Stool	Measurement of 16S RNA, shotgun metagenomics, and metabolomics via stool specimen.	Collected twice by the participant at home between Visit 1 and Visit 2, lasting no more than 2 weeks after the first appointment.
Microbiome - Blood	Measurement of 16S RNA, shotgun metagenomics, and metabolomics via blood specimen.	Collected once at Day1.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Systolic and Diastolic Blood Pressure	Measurement of the pressure of circulating blood at rest.	Measured once at Day 1.
Questionnaire Data - Diet	Use of validated surveys including the Food Frequency questionnaire, Food choice questionnaire.	Self-reported by the participant at home between Visit 1 and Visit 2, lasting no more than 2 weeks after the first appointment.
Questionnaire Data - Stressors	Use of validated surveys including, Social isolation scale, Social network engagement, Family cohesion, Acculturative stress, Perceived stress scale, Everyday Discrimination, and major discrimination.	Self-reported by the participant at home between Visit 1 and Visit 2, lasting no more than 2 weeks after the first appointment.
Anthropometrics - waist & hip circumference	Measurement of waist and hip circumference(cm).	Measured once at Day 1.
Anthropometrics - BMI	Measurement of height(in) and weight(lbs), used to calculate BMI.	Measured once at Day 1.
Questionnaire Data - Physical Activity	Use of validated surveys including the international physical activity questionnaire.	Self-reported by the participant at home between Visit 1 and Visit 2, lasting no more than 2 weeks after the first appointment.
Questionnaire Data - Health	Use of validated surveys including the health eating index.	Self-reported by the participant at home between Visit 1 and Visit 2, lasting no more than 2 weeks after the first appointment.
Questionnaire Data - Ingestive Behaviors	Use of validated surveys including the Yale food addiction scale, Three-Factor Eating questionnaire, Reward-based eating drive, General food craving questionnaire - trait-reduced, Cravings and Want to eat Assessments to food cues.	Self-reported by the participant at home between Visit 1 and Visit 2, lasting no more than 2 weeks after the first appointment.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Differences in Multimodal Brain Signatures	Neuroimaging of participants brain via MRI procedure.	Measured at optional follow up visit at 3 and/or 6 month mark. Scan lasts about 1.5 hour.
Differences in Microbiome - Stool	Measurement of 16S RNA, shotgun metagenomics, and metabolomics via stool specimen.	Collected twice by the participant at home before the 3 and/or 6 month follow up appointment, occurring approximately 3 and 6 months after the second (MRI) appointment.
Differences in Microbiome - Blood	Measurement of 16S RNA, shotgun metagenomics, and metabolomics via blood specimen.	Collected once at the 3 and/or 6month follow up appointment, occurring approximately 3 and 6months after the second (MRI) appointment.

Collaborators and Investigators

• Sponsor: University of California, Los Angeles

Study record dates

Study Major Dates

• Study Start (Actual): August 24, 2021
• Primary Completion (Anticipated): December 1, 2024
• Study Completion (Anticipated): December 1, 2024

Study Registration Dates

• First Submitted: October 21, 2021
• First Submitted That Met QC Criteria: November 2, 2021
• First Posted (Actual): November 16, 2021

Study Record Updates

• Last Update Posted (Estimate): January 10, 2023
• Last Update Submitted That Met QC Criteria: January 9, 2023
• Last Verified: January 1, 2023

More Information

Terms related to this study

• Keywords: MRI; Overweight; Obese; Mexican Women; Filipina Women; Brain-Gut Microbiome; Metabolome
• Other Study ID Numbers: IRB # 20-002326

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No
• IPD Plan Description: At this time there is no plan to make the de-identified data available for sharing with other researchers.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No