Constipation - FunctionalNCT07797491
Breath Gases, Gut Flora, and Immunity in Children With Constipation
An observational study of Constipation - Functional, run by Ruijin Hospital at 1 site in China.
Trial summary
Constipation is a common problem in children that can affect their daily life, school performance, and social activities. Researchers have found that the bacteria living in our intestines (called "gut microbiome") may play an important role in constipation. Read more about this study
- Who is it for?
- Ages 6 to 14 yearsHealthy volunteers can take part
- Conditions the study is for
- Constipation - Functional
- How many people
- 200 participants
- Where
- 1 siteChina
- Study dates
- 1 Jan 2026to 31 Dec 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 6 to 14 years
- All sexes
- Healthy volunteers accepted
- Child
Study population: Children aged 6 to 14 years recruited from the outpatient clinic of the Department of Pediatrics at Ruijin Hospital (North Campus), Shanghai, China. The study population includes two groups: (1) children diagnosed with functional constipation according to Rome criteria, and (2) healthy children undergoing routine health check-ups with no chronic or acute digestive disorders. All participants must have no recent (within 4 weeks) exposure to antibiotics, probiotics, or medications affecting gastrointestinal motility. Informed consent is obtained from the legal guardian of each participant.
Who may be able to join
- Children aged 6 to 14 years, male or female.
- Legal guardian provides written informed consent.
- No use of antibiotics, probiotics, lactulose, antacids, or gastrointestinal prokinetic agents within 4 weeks prior to enrollment.
- For the constipation group: Clinical diagnosis of functional constipation according to Rome criteria, defined as meeting at least two of the following criteria for two consecutive months: (a) fewer than two bowel movements per week; (b) at least one episode of fecal incontinence per week; (c) history of massive fecal retention or posturing related to fecal retention; (d) history of painful or difficult defecation; (e) presence of a large fecal mass in the rectum; (f) passage of stools large enough to obstruct the toilet. Additionally, no enema or acute enteritis within 2 weeks prior to enrollment.
- For the healthy control group: No chronic digestive diseases or acute illnesses; no enema or acute enteritis within 2 weeks prior to enrollment.
Who cannot join
- Use of antibiotics, probiotics, lactulose, antacids, or gastrointestinal prokinetic agents within 4 weeks prior to enrollment (if not already excluded at screening).
- Clinically significant abnormalities in liver, kidney, neurological, respiratory, or coagulation function as determined by the investigator.
- Unstable vital signs.
- Presence of other underlying systemic diseases (e.g., metabolic, endocrine, or organic gastrointestinal disorders).
- Any other condition that, in the investigator's opinion, makes the participant unsuitable for enrollment.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Correlation Study on End-expiratory NO, H2S, H2, CH4, Intestinal Flora and Immune Function in Children With Constipation
Constipation is a common problem in children that can affect their daily life, school performance, and social activities. Researchers have found that the bacteria living in our intestines (called "gut microbiome") may play an important role in constipation. However, we still do not fully understand exactly how these bacteria affect constipation in children.
This study aims to explore whether the gases children breathe out-including nitric oxide (NO), hydrogen sulfide (H₂S), hydrogen (H₂), and methane (CH₄)-can tell us something about the bacteria in their guts. By comparing children with constipation to healthy children, we hope to find out:
Whether the gases in their breath are different Whether the types of bacteria in their guts are different Whether there is a relationship between breath gases and gut bacteria If we find clear connections, this could lead to a simple, non-invasive breath test that doctors can use to understand a child's gut health without the need for more invasive procedures.
Read the detailed description
Childhood functional constipation (FC) is a multifactorial syndrome with a global prevalence of approximately 9.5% among pediatric populations, accounting for up to 29% of functional gastrointestinal disorders. It significantly affects physical health, academic performance, and psychosocial development, with approximately 25% of affected children continuing to experience gastrointestinal symptoms into adulthood. While conventional factors such as diet, fluid intake, and psychological stress have been implicated, the precise pathophysiological mechanisms remain incompletely understood.
Emerging evidence highlights the critical role of the gut microbiome in regulating intestinal motility and visceral sensitivity through the microbiota-gut-brain axis. Microbial metabolites-including short-chain fatty acids (SCFAs), serotonin, bile acids, and gases (methane, hydrogen, hydrogen sulfide)-serve as key signaling molecules that influence enteric neurotransmission, smooth muscle contraction, and gastrointestinal transit time. Notably, hydrogen (H₂) and methane (CH₄) are exclusively of microbial origin (produced via anaerobic fermentation of carbohydrates by intestinal flora), while hydrogen sulfide (H₂S) is generated both endogenously and by sulfate-reducing bacteria. Nitric oxide (NO), though primarily endogenously produced, may also reflect intestinal inflammatory status and microbial metabolic activity.
The integration of breath gas analysis and metagenomic profiling offers a promising, non-invasive approach to elucidate host-microbe interactions in FC. However, systematic evaluations linking these four exhaled gases (NO, H₂S, H₂, CH₄) to the taxonomic and functional composition of the gut microbiome in constipated children remain scarce. This study is designed to bridge this knowledge gap, providing mechanistic insights and potentially establishing breath testing as a surrogate marker for gut dysbiosis in pediatric constipation.
- Conditions
- Constipation - Functional
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Constipation Group | Children aged 6 to 14 years diagnosed with functional constipation according to Rome criteria (at least two of the following for two consecutive months: fewer than two bowel movements per week; at least one episode of fecal incontinence per week; history of massive fecal retention or posturing related to fecal retention; history of painful or difficult defecation; presence of a large fecal mass in the rectum; passage of stools large enough to obstruct the toilet). Participants have not used antibiotics, probiotics, lactulose, antacids, or prokinetic agents within 4 weeks prior to enrollment, and have not received enema or had acute enteritis within 2 weeks. Intervention: Non-interventional; participants undergo a one-time breath test (end-expiratory NO, H₂S, H₂, CH₄), stool collection (within 2 days), and blood draw (2 mL). | |
| Control Group | Healthy children aged 6 to 14 years with no chronic digestive diseases or acute illnesses, recruited from routine health check-up visits. Participants have not used antibiotics, probiotics, lactulose, antacids, or prokinetic agents within 4 weeks prior to enrollment. Intervention: Non-interventional; participants undergo a one-time breath test (end-expiratory NO, H₂S, H₂, CH₄), stool collection (within 2 days), and blood draw (2 mL). |
What is being measured
The primary outcome is the main question the study is designed to answer.
End-expiratory concentrations and peak values of H2
Comparison of the fasting end-expiratory concentrations (ppm) and peak values of hydrogen (H2) between children with functional constipation and healthy controls. Breath samples are collected during a single morning session after an overnight fast using a validated portable breath analyzer.
Measured: Measured at baseline (single time point) after an overnight fast, during a single methane-hydrogen breath test session.
Secondary outcomes (3)
End-expiratory concentrations and peak values of H2S
Comparison of the fasting end-expiratory concentrations (ppm) and peak values of hydrogen sulfide (H2S) between children with functional constipation and healthy controls. Breath samples are collected during a single morning session after an overnight fast using a validated portable breath analyzer.
Measured: Measured at baseline (single time point) after an overnight fast, during a single methane-hydrogen breath test session.
End-expiratory concentration and peak value of methane (CH₄)
Comparison of fasting end-expiratory CH₄ concentration (ppm) and peak values between children with functional constipation and healthy controls. CH₄ is exclusively produced by methanogenic archaea in the gut and is not metabolized by mammalian cells. Elevated CH₄ levels (e.g., ≥10 ppm) are associated with prolonged colonic transit time and increased constipation severity. The analysis will compare intergroup differences in both baseline concentration and maximum peak values during the breath test.
Measured: Measured at baseline (single time point) after an overnight fast, during a single methane-hydrogen breath test session.
End-expiratory concentration and peak value of nitric oxide (NO)
Comparison of fasting end-expiratory NO concentration (ppb) and peak values between children with functional constipation and healthy controls. End-expiratory NO reflects systemic and intestinal inflammatory status. Alterations in NO levels may indicate mucosal barrier dysfunction or low-grade inflammation associated with constipation. The analysis will compare intergroup differences in both baseline concentration and maximum peak values.
Measured: Measured at baseline (single time point) after an overnight fast, during a single methane-hydrogen breath test session.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Sep 2026
- Study start1 Jan 2026
- Primary completion31 Dec 2027 (estimated)
- Study completion31 Dec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Constipation - FunctionalStudies of the same condition, open and under way.
- More trials run by Ruijin HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Prospective
- Enrolment
- 200 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Ruijin Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07797491
- Sponsor's protocol ID
- C001
- Status last verified
- Aug 2026
- First submitted
- 17 Aug 2026
- Last updated
- 1 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data (IPD) will not be shared publicly due to the following reasons: (1) This is a single-center observational study with a relatively small sample size (N=200), and the data are collected specifically for the exploratory objectives of this protocol; (2) The study involves pediatric participants (ages 6-14), and the informed consent form, approved by the institutional ethics committee, does not include provisions for sharing individual-level data with external investigators; (3) The data include sensitive genomic (metagenomic sequencing) and metabolomic profiles, which may carry re-identification risks; (4) The research team lacks the infrastructure and funding to support data anonymization, transfer, and external curation at this time. Summary-level results will be disseminated through peer-reviewed publications and conference presentations.
Study at a glance
From the registry record, last updated by the sponsor on 1 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Correlation Study on End-expiratory NO, H2S, H2, CH4, Intestinal Flora and Immune Function in Children With Constipation
- ClinicalTrials.gov ID
- NCT07797491
- Acronym / sponsor ID
- C001
- Conditions
- Constipation - Functional
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 200 participants (estimated)
- Lead sponsor
- Ruijin HospitalUniversity, hospital or other
- Study start
- 1 Jan 2026 (actual)
- Primary completion
- 31 Dec 2027 (estimated)
- Study completion
- 31 Dec 2027 (estimated)
- First posted
- 1 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Constipation is a common problem in children that can affect their daily life, school performance, and social activities. Researchers have found that the bacteria living in our intestines (called "gut microbiome") may play an important role in constipation. However, we still do not fully understand exactly how these bacteria affect constipation in children.
This study aims to explore whether the gases children breathe out-including nitric oxide (NO), hydrogen sulfide (H₂S), hydrogen (H₂), and methane (CH₄)-can tell us something about the bacteria in their guts. By comparing children with constipation to healthy children, we hope to find out:
Whether the gases in their breath are different Whether the types of bacteria in their guts are different Whether there is a relationship between breath gases and gut bacteria If we find clear connections, this could lead to a simple, non-invasive breath test that doctors can use to understand a child's gut health without the need for more invasive procedures.
Detailed description
Childhood functional constipation (FC) is a multifactorial syndrome with a global prevalence of approximately 9.5% among pediatric populations, accounting for up to 29% of functional gastrointestinal disorders. It significantly affects physical health, academic performance, and psychosocial development, with approximately 25% of affected children continuing to experience gastrointestinal symptoms into adulthood. While conventional factors such as diet, fluid intake, and psychological stress have been implicated, the precise pathophysiological mechanisms remain incompletely understood.
Emerging evidence highlights the critical role of the gut microbiome in regulating intestinal motility and visceral sensitivity through the microbiota-gut-brain axis. Microbial metabolites-including short-chain fatty acids (SCFAs), serotonin, bile acids, and gases (methane, hydrogen, hydrogen sulfide)-serve as key signaling molecules that influence enteric neurotransmission, smooth muscle contraction, and gastrointestinal transit time. Notably, hydrogen (H₂) and methane (CH₄) are exclusively of microbial origin (produced via anaerobic fermentation of carbohydrates by intestinal flora), while hydrogen sulfide (H₂S) is generated both endogenously and by sulfate-reducing bacteria. Nitric oxide (NO), though primarily endogenously produced, may also reflect intestinal inflammatory status and microbial metabolic activity.
The integration of breath gas analysis and metagenomic profiling offers a promising, non-invasive approach to elucidate host-microbe interactions in FC. However, systematic evaluations linking these four exhaled gases (NO, H₂S, H₂, CH₄) to the taxonomic and functional composition of the gut microbiome in constipated children remain scarce. This study is designed to bridge this knowledge gap, providing mechanistic insights and potentially establishing breath testing as a surrogate marker for gut dysbiosis in pediatric constipation.
Study design
- Observational model
- Case-control
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Constipation Group | – | –Children aged 6 to 14 years diagnosed with functional constipation according to Rome criteria (at least two of the following for two consecutive months: fewer than two bowel movements per week; at least one episode of fecal incontinence per week; history of massive fecal retention or posturing related to fecal retention; history of painful or difficult defecation; presence of a large fecal mass in the rectum; passage of stools large enough to obstruct the toilet). Participants have not used antibiotics, probiotics, lactulose, antacids, or prokinetic agents within 4 weeks prior to enrollment, and have not received enema or had acute enteritis within 2 weeks. Intervention: Non-interventional; participants undergo a one-time breath test (end-expiratory NO, H₂S, H₂, CH₄), stool collection (within 2 days), and blood draw (2 mL). |
| Control Group | – | –Healthy children aged 6 to 14 years with no chronic digestive diseases or acute illnesses, recruited from routine health check-up visits. Participants have not used antibiotics, probiotics, lactulose, antacids, or prokinetic agents within 4 weeks prior to enrollment. Intervention: Non-interventional; participants undergo a one-time breath test (end-expiratory NO, H₂S, H₂, CH₄), stool collection (within 2 days), and blood draw (2 mL). |
Who may qualify
- Ages
- 6 to 14 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
- Study population
- Children aged 6 to 14 years recruited from the outpatient clinic of the Department of Pediatrics at Ruijin Hospital (North Campus), Shanghai, China. The study population includes two groups: (1) children diagnosed with functional constipation according to Rome criteria, and (2) healthy children undergoing routine health check-ups with no chronic or acute digestive disorders. All participants must have no recent (within 4 weeks) exposure to antibiotics, probiotics, or medications affecting gastrointestinal motility. Informed consent is obtained from the legal guardian of each participant.
Key inclusion criteria (5 listed)
- Children aged 6 to 14 years, male or female.
- Legal guardian provides written informed consent.
- No use of antibiotics, probiotics, lactulose, antacids, or gastrointestinal prokinetic agents within 4 weeks prior to enrollment.
- For the constipation group: Clinical diagnosis of functional constipation according to Rome criteria, defined as meeting at least two of the following criteria for two consecutive months: (a) fewer than two bowel movements per week; (b) at least one episode of fecal incontinence per week; (c) history of massive fecal retention or posturing related to fecal retention; (d) history of painful or difficult defecation; (e) presence of a large fecal mass in the rectum; (f) passage of stools large enough to obstruct the toilet. Additionally, no enema or acute enteritis within 2 weeks prior to enrollment.
- For the healthy control group: No chronic digestive diseases or acute illnesses; no enema or acute enteritis within 2 weeks prior to enrollment.
Key exclusion criteria (5 listed)
- Use of antibiotics, probiotics, lactulose, antacids, or gastrointestinal prokinetic agents within 4 weeks prior to enrollment (if not already excluded at screening).
- Clinically significant abnormalities in liver, kidney, neurological, respiratory, or coagulation function as determined by the investigator.
- Unstable vital signs.
- Presence of other underlying systemic diseases (e.g., metabolic, endocrine, or organic gastrointestinal disorders).
- Any other condition that, in the investigator's opinion, makes the participant unsuitable for enrollment.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
End-expiratory concentrations and peak values of H2
Time frame: Measured at baseline (single time point) after an overnight fast, during a single methane-hydrogen breath test session.
Comparison of the fasting end-expiratory concentrations (ppm) and peak values of hydrogen (H2) between children with functional constipation and healthy controls. Breath samples are collected during a single morning session after an overnight fast using a validated portable breath analyzer.
3 secondary outcomes
End-expiratory concentrations and peak values of H2S
Time frame: Measured at baseline (single time point) after an overnight fast, during a single methane-hydrogen breath test session.
End-expiratory concentration and peak value of methane (CH₄)
Time frame: Measured at baseline (single time point) after an overnight fast, during a single methane-hydrogen breath test session.
End-expiratory concentration and peak value of nitric oxide (NO)
Time frame: Measured at baseline (single time point) after an overnight fast, during a single methane-hydrogen breath test session.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 Sep 2026.
- Individual participant dataSharing planned: No. Individual participant data (IPD) will not be shared publicly due to the following reasons: (1) This is a single-center observational study with a relatively small sample size (N=200), and the data are collected specifically for the exploratory objectives of this protocol; (2) The study involves pediatric participants (ages 6-14), and the informed consent form, approved by the institutional ethics committee, does not include provisions for sharing individual-level data with external investigators; (3) The data include sensitive genomic (metagenomic sequencing) and metabolomic profiles, which may carry re-identification risks; (4) The research team lacks the infrastructure and funding to support data anonymization, transfer, and external curation at this time. Summary-level results will be disseminated through peer-reviewed publications and conference presentations.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Constipation - Functional, run by Ruijin Hospital at 1 site in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 1 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
End-expiratory concentrations and peak values of H2 (time frame: Measured at baseline (single time point) after an overnight fast, during a single methane-hydrogen breath test session.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 Sep 2026.