An observational study in All Health Backgrounds to Determine a Baseline of Flatus Activity, sponsored by University of Maryland, College Park. Recruiting at 2 sites in United States. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-12-23.
Sponsored by University of Maryland, College Park · Observational
The goal of this observational study is to quantify the typical frequency of flatulence in healthy adults, normalized by fiber intake, using the Smart Underwear device. The study will enroll a maximum of 500 adults across the United States who will wear the device for three consecutive days while continuing their usual daily activities.
The main questions it aims to answer are:
Researchers will collect gas sensor data from the Smart Underwear device alongside dietary information logged in a mobile app to assess the relationship between diet and microbiome activity.
Participants will:
All study procedures will be conducted remotely. Data will be analyzed in de-identified form to evaluate baseline flatulence patterns, normalized to fiber intake, in the general adult population.
42 studies on the registry are indexed under Flatulence; 7 are open to participants now.
Browse Flatulence studies →University of Maryland, College Park is the lead sponsor of 62 studies on the registry; 15 are open to participants now.
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Residents of the US
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Exclusion Criteria:
American adults that are at least 18 years old, live in the United States, are not pregnant or lactating, and agree to wear the Smart Underwear device.
Microbiome Activity Index
The Microbiome Activity Index is a composite measure reflecting gut microbiome activity, calculated from both flatus frequency and hydrogen gas concentration. The index uses the absolute value of the first derivative of the hydrogen sensor signal to better capture flatus intensity, reduce baseline noise, and mitigate sensor saturation at high hydrogen levels. This composite approach ensures a more accurate representation of gut microbiome activity than relying on flatus count or hydrogen concentration alone. Data are collected using a wearable device ("Smart Underwear") and uploaded to the Human Flatus Atlas app.
Time frame: 12 hours each day for 3 days
Total flatus count
The total number of flatus events detected by the wearable device. Detection is based on hydrogen gas concentration changes and signal rate-of-change analysis.
Time frame: 12 hours each day for 3 days
Flatus Per Hour
The rate of flatus events normalized per hour, calculated from the total number of events and the total monitored time.
Time frame: 12 hours each day for 3 days
Microbiome Activity Index Comparative Score
A relative score comparing the participant's Microbiome Activity Index to aggregated anonymized results from other individuals in the Human Flatus Atlas study. Presented as a percentile rank or standardized score.
Time frame: 12 hours each day for 3 days
Fiber-Normalized Flatus Frequency
The participant's flatus frequency (events/day) normalized by self-reported dietary fiber intake (grams/day). Normalization will allow assessment of typical adult flatulence frequency in relation to fiber consumption.
Time frame: 12 hours each day for 3 days
Plan to share: Yes — We plan to share de-identified, aggregate individual participant data limited to total enrollment numbers and demographic characteristics (e.g., age range, sex distribution, and other baseline variables) collected during the study. No other data, including outcome or clinical data, will be shared. Supporting Information The shared dataset will not contain any information that could directly or indirectly identify participants. Data will be available in aggregate format only, and will be provided upon reasonable request from qualified researchers for the purposes of scientific transparency and verification of study population characteristics.
Supporting information: Study protocol
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University of Maryland, College Park