Effects of CO Level on Pain, Sensory Function, and Subjective Health
Trial statusNot yet recruiting
Trial phaseNot listed
Trial typeObservational
Biological sexAll
Age18-65
SponsorIzmir Democracy University
About this trial
Carbon monoxide (CO) is a colorless and odorless gas that can enter the human body through environmental exposure and especially tobacco use. CO binds to hemoglobin with a much higher affinity than oxygen, thereby reducing oxygen transport to tissues. This condition may lead to various physiological and psychological effects, particularly on the nervous system.
In the literature, CO exposure has mainly been investigated in the context of acute poisoning cases and smoking-related effects. However, studies evaluating the effects of low-level and chronic CO exposure-more commonly encountered in the general population-on pain perception, sensory functions, and psychological status are limited.
Tobacco smoke is an important source of CO, and exhaled CO levels have been shown to be significantly higher in smokers and associated with various neurocognitive changes. Evidence suggests that CO exposure may influence anxiety, depression, attention, and cognitive functions. In addition, some studies indicate that CO may affect brain regions involved in pain perception and emotional regulation.
However, there is insufficient research examining the relationship between low-level carbon monoxide exposure and pain threshold, sensory functions, anxiety, depression, and subjective health complaints within the same study framework.
This study aims to evaluate the relationship between exhaled carbon monoxide (CO) levels and pain threshold, sensory functions, anxiety, depression, and subjective health complaints in healthy adults. By examining the multidimensional effects of low-level CO exposure, the study seeks to fill an important gap in the literature and provide a more comprehensive understanding of this issue.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Being between the ages of 18 and 65
Disqualifiers
None
Trial population
This study will include healthy adult participants aged 18-65 years with a history of regular smoking for at least the past 6 months. Participants will be free of respiratory, cardiovascular, neurological, and psychiatric diseases, and will not have any acute infection or recent surgery affecting respiratory muscles.
Trial design
Design model
Cohort
Time perspective
Prospective
Treatments tested in this trial
Not listed
Trial groups
70 Participants
are grouped into 1 trial groupGroup A: Healthy Adults - CO Exposure
Trial outcomes
Primary outcomes
1
Exhaled Carbon Monoxide (CO) Level
Exhaled carbon monoxide levels will be measured using a Bedfont Smokerlyzer-piCO+ device. Participants will be instructed to take a deep breath, hold their breath for 15 seconds, and then exhale slowly and completely into the device mouthpiece. The measured CO values will be classified as follows: 0-6 ppm: non-smoker 7-10 ppm: light exposure 11-15 ppm: regular smoker 16-25 ppm: heavy smoker 25 ppm: very heavy smoker
Time frame
June 2026- July 2026Secondary outcomes
1
Pain Threshold Measurement
Pressure pain thresholds will be assessed using an algometer, which is a validated and reliable tool for measuring muscle and soft tissue sensitivity. The device consists of a 1 cm diameter rubber-tipped metal probe attached to a pressure gauge measuring force in kilograms and pounds. Pressure pain thresholds will be measured bilaterally at the upper, middle, and lower portions of the trapezius muscle
Time frame
June 2026- July 20262
Beck Anxiety Inventory (BAI)
Anxiety levels will be assessed using the Beck Anxiety Inventory, a 21-item self-report questionnaire. Each item will be scored between 0 and 3, with total scores ranging from 0 to 63. Higher scores will indicate greater anxiety severity.
Time frame
June 2026- July 20263
Beck Depression Inventory (BDI)
Depressive symptoms will be evaluated using the Beck Depression Inventory, a 21-item self-report scale assessing cognitive, emotional, motivational, and somatic symptoms of depression. Each item will be scored from 0 to 3, with total scores ranging from 0 to 63. Higher scores will indicate more severe depressive symptoms.
Time frame
June 2026- July 20264
Semmes-Weinstein Monofilament Test
Sensory function will be assessed using the Semmes-Weinstein monofilament test, a widely used method for evaluating light touch and pressure perception. Monofilaments ranging from 0.086 gm to 448 gm will be applied in ascending order. Testing will be performed from distal to proximal regions, including the anterior and posterior surfaces of all fingers. The smallest detectable monofilament will be recorded. When the filament bends, the applied force will be considered constant, and participants' perception will be recorded accordingly
Time frame
June 2026- July 2026Locations
Sponsors and contacts
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Source ClinicalTrials.gov
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