Gut changes studied in people with untreated Parkinson's disease
Studies gut structure, function and bacteria in untreated Parkinson's patients and healthy controls.
Plain-language title generated from the registry record
Registry title: Untreated Parkinson's Disease Work-up Assessing Resident Microbiota and Duodenal Barrier Function
Key facts
- Where
- Leuven, BelgiumSee the site
Could this be for you?
Answer for yourself. This is not a decision: only the study team can say whether you can take part.
- Are you between 18 and 75 years old?
Source: NCT07418658, who can take part
Where in Belgium
- UZ LeuvenLeuven, BelgiumNo longer taking part
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Trial details
- Who runs it
- Universitaire Ziekenhuizen KU Leuven
- Trial code
- NCT07418658
- Record updated
- 18 February 2026
- Original description
The UPWARD study is a prospective hypothesis-generating study in individuals with untreated Parkinson's disease (PD) and age-matched healthy controls (HCs). The objective of the study is to characterise disease-driven gastrointestinal (GI) changes that occur prior to initiation of treatment.Read full original descriptionShow less
Multimodal Characterization of Gastrointestinal Structure, Function, and Microbiome in Drug-Naïve Parkinson's Disease
The UPWARD study is a prospective hypothesis-generating study in individuals with untreated Parkinson's disease (PD) and age-matched healthy controls (HCs). The objective of the study is to characterise disease-driven gastrointestinal (GI) changes that occur prior to initiation of treatment.
The main questions this study aims to answer are:
1. Are there changes in duodenal permeability in people with untreated PD? 2. Are there changes in the gut microbiome in people with untreated PD? 3. Are these gut changes linked to prodromal features, or movement and non-movement symptoms of PD?
The study consists of a screening visit, followed by a six-day home phase and one subsequent study visit at UZ Leuven. During the home phase, participants collect a stool sample, ingest radiopaque markers to assess gut transit time, and complete questionnaires. During the study visit, participants undergo an abdominal X-ray, a clinical assessment, and blood sampling. An upper GI endoscopy with duodenal biopsies is offered as an optional component of the study.
This study does not test a therapeutic intervention. Examinations as part of the study are not standard clinical care. The findings are expected to improve understanding of early GI involvement in PD and to inform future mechanistic and clinical research.
Inclusion criteria:; Patients eligible for inclusion in this study must meet all of the following criteria:; Diagnosis of Parkinson's Disease by a neurologist according to the Movement Disorder Society Clinical Diagnostic Criteria for PD; Signed informed consent form; Aged 18-75 years old; Able to understand the study and questionnaires, and comply with study requirements; Controls eligible for inclusion in this study must meet all of the following criteria:; Aged 40-75 years old; Signed informed consent form; Able to understand the study and questionnaires, and comply with study requirements; Exclusion criteria:; Participants eligible for this study must not meet any of the following criteria:; Patients and controls:; Gastrointestinal: diagnosis of organic gastrointestinal diseases potentially affecting the assessments during the study (e.g. inflammatory bowel disease (IBD), celiac disease, eosinophilic diseases of the gastro-intestinal tract, gastro-intestinal cancer, diverticulitis in the last 6 months, GI infection in the last 3 months, …); Surgery: major abdominal surgery (including, but not limited to: cholecystectomy, colectomy, hiatal hernia repair, …) except for uncomplicated appendectomy, splenectomy and inguinal hernia repair; Medication use:; Any previous exposure to medication used in the treatment of motor symptoms of Parkinson's disease (levodopa, dopamine agonists, MAO-B inhibitors, COMT-inhibitors, NMDA-receptor antagonists, anticholinergics); Antibiotics use in the last 3 months; Use of PPI in the last month; Use of NSAID in the last month; Use of anticoagulation4 (including vitamin K antagonists (VKA), direct oral anticoagulants (DOAC) or low-molecular weight heparins (LMWH)) or dual antiplatelet therapy4 (DUAPT; Acetylsalicilic acid (Asaflow®) + P2Y12-inhibitor (Clopidogrel®)); Pregnancy and breastfeeding; Other: Cancer and/or adjuvant treatment within the last 6 months; Exposures:; Food intoxication in the last 3 months; Consumptom of more than 2 standard units of alcohol per day; Patients (additional criteria); Neurological: any major neurological disorder other than Parkinson's disease; Controls (additional criteria); Neurological:; A diagnosis of Parkinson's disease or any other major neurological disorder other than Parkinson's disease; Clinical signs of parkinsonism; First degree relative(s) with Parkinson's disease; Gastrointestinal: subjects fulfilling a clinical diagnosis of either Functional dyspepsia, Functional constipation, or Irritable bowel syndrome based on the ROME-IV diagnostic criteria.