Impact of Olfactory Odour StimulatioN on Energy EXpenditure

Study Overview
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Brief Summary
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In this preliminary short-term study it is investigated, whether a short olfactory stimulation with distinct odours impacts energy expenditure in patients with obesity and lean patients.

Official Title
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SNEEX - Impact of Olfactory Odour StimulatioN on Energy EXpenditure

Conditions
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Obesity

Intervention / Treatment
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* Other: Olfactory Stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: • Age 18-55 years Obesity (BMI ≥30 kg/m2) and Lean (BMI 18-25 kg/m2) Written informed consent Normosmia (defined by sniffing Sticks test) Exclusion Criteria: • Chronic or acute sinusitis Surgical intervention of the nasal cavity or the paranasal sinus Known allergy to odors used in the study Smokers Current illicit drug abuse including daily marijuana and cannabidiol (CBD) consumption (alcohol ≤2 drinks per day allowed) Any kind of severe chronic disease (e.g. severe heart failure, active cancer disease) Diabetes mellitus Treatment with insulin sensitizing drugs including Glucagon-like Peptide (GLP)-1 analogues within the last 3 months History of neurodegenerative diseases, severe head trauma Severe renal impairment (e.g. estimated glomerular filtration rate <30 ml/min/m2) Known liver cirrhosis or other severe liver impairment Use of any kind of decongestant more than twice a week Use of cortisone-containing nasal spray within the last 3 months Acute upper respiratory tract infection Uncontrolled dysthyroidism Uncontrolled hypertension Regular use of psychopharmaceutic drugs Study participants aims to start a new diet or exercise program during the study Bariatric surgery Pregnancy/Lactation Onset of climacteric symptoms within one year (e.g. hot flashes and/or diaphoresis) OR initiation of hormonal replacement therapy in the last three months Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc. Participation in an interventional study within the last 3 months

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Obese<br>Age 18-55 years Obesity (BMI ≥30 kg/m2) Written informed consent Normosmia (defined by sniffing Sticks test) | Other: Olfactory Stimulation<br>* Participants are exposed to different odours and energy expenditure is assessed via indirect calorimetry.<br>* Other names: Different odours;|
| Other: Lean<br>Age 18-55 years Lean (BMI 18-25 kg/m2) Written informed consent Normosmia (defined by sniffing Sticks test) | Other: Olfactory Stimulation<br>* Participants are exposed to different odours and energy expenditure is assessed via indirect calorimetry.<br>* Other names: Different odours;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Energy Expenditure | change in energy expenditure as assessed via calorimetry after olfactory stimulation with different odours. | 6 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Energy Expenditure, Additional Odours | Change in energy expenditure as assessed via calorimetry after olfactory stimulation with Different odours | 6 hours | 
| Heart Rate | change in heart rate variability upon olfactory stimulation with different odors as assessed via continuous ECG | 6 hours | 
| Blood Pressure | Change in blood pressure upon olfactory stimulation with different odors as assessed via a blood pressure cuff at the upper arm according to Riva Rocci | 6 hours | 
| Metabolic Parameters | Change in metabolic blood parameters upon acute olfactory stimulation with different odours | 6 hours | 
| Glucose Levels | change in interstitial fluid glucose levels upon olfactory stimulation with different odours | 6 hours |