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NCT Number: NCT07474623

Effects of Nicotine Dependence on Multidimensional Health Outcomes

Nicotine, a major toxic component of cigarette smoke, together with carbon monoxide (CO), constitutes a significant environmental exposure with systemic effects. Beyond its addictive potential, chronic nicotine exposure may induce inflammation, oxidative stress, tissue hypoxia, and autonomic imbalance, potentially impairing respiratory muscle strength, functional capacity, and overall physical performance. Additionally, nicotine dependence has been associated with sleep disturbances, cognitive dysfunction, altered pain perception, and reduced quality of life.

Although previous studies have examined individual effects of smoking on specific health outcomes, research addressing these multidimensional impacts within a comprehensive framework remains limited. Therefore, this study aims to investigate the relationship between nicotine dependence level and respiratory muscle strength, functional capacity, cognitive functions, pain, quality of life, physical activity level, and sleep quality, in order to provide a more holistic understanding of the clinical consequences of nicotine dependence.

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Key information

Conditions

Tobacco Use Disorder Chemically-Induced Disorders Mental Disorders Nicotine Dependence, Cigarettes Substance-Related Disorders

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Betül TAŞPINAR

Konak, İ̇zmi̇r, Turkey (Türkiye)

About this study

One of the toxic components found in cigarette smoke, nicotine, together with carbon monoxide (CO), represents an important environmental exposure. Nicotine is the primary component responsible for the addictive potential of tobacco products and rapidly enters the systemic circulation, spreading to both the central and peripheral nervous systems. In addition, the systemic effects of nicotine may influence the oxygenation capacity of respiratory muscles and overall functional performance. Long-term nicotine exposure may trigger inflammatory and oxidative stress responses, which are thought to contribute to reduced respiratory muscle performance.

Sleep disturbances and attention-concentration problems associated with nicotine dependence negatively affect both quality of life and cognitive functions. Studies examining the effects of smoking status on functional capacity have shown that nicotine exposure plays a limiting role in exercise capacity and activities of daily living. One study reported that smokers had significantly lower exercise capacity and physical activity levels in daily life compared to non-smokers. The same study also demonstrated that smoking has a negative impact on the physical components of quality of life and may adversely affect functional independence.

Chronic tobacco exposure contributes to hyperalgesia through multidimensional mechanisms, including dysfunction of central pain modulation pathways, activation of proinflammatory processes, and tissue damage. Research has shown that nicotine dependence sensitizes pain perception, increases pain intensity, and complicates pain management processes. Nicotine has also been found to be directly associated with prolonged sleep latency, reduced total sleep time, and decreased slow-wave sleep, which has restorative properties. Considering that the pathophysiology of common sleep disorders has not yet been fully elucidated, we hypothesize that there may also be a relationship between CO exposure and sleep disturbances.

Chronic nicotine exposure may lead to tissue hypoxia, thereby reducing physical endurance and participation in daily activities. Furthermore, nicotine-induced mitochondrial dysfunction, oxidative stress, and autonomic imbalance may negatively affect general health perception and psychological well-being through symptoms such as fatigue, headache, and cognitive fog. Impaired sleep quality and the presence of cardiorespiratory symptoms may further limit social, occupational, and personal functioning.

Taken together, these effects suggest that nicotine dependence may lead to reductions in quality of life components and cognitive functions. Given the limited number of studies addressing the multifaceted effects of nicotine within a holistic framework, we anticipate that our study-investigating the relationship between nicotine dependence level and respiratory muscle strength, functional capacity, cognitive functions, pain, quality of life, physical activity level, and sleep quality-will contribute significantly to filling existing gaps in the literature.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Regular cigarette use for at least the past 6 months
  • No history of respiratory, cardiovascular, or neurological/psychiatric disease
  • No recent history of surgery or trauma that could affect respiratory muscles
  • No current acute infection (especially upper or lower respiratory tract infections)

Exclusion criteria

  • Presence of chronic respiratory diseases such as COPD or
  • History of cardiovascular disease
  • Diagnosed neurological or psychiatric disorders
  • history of surgery or trauma affecting the respiratory muscles within the last 3 months
  • Pregnancy or suspected pregnancy

Treatment and study plan

Comprehensive Clinical Assessment

Other

Participants will undergo a comprehensive clinical assessment including evaluation of nicotine dependence level (Fagerström Test for Nicotine Dependence), respiratory muscle strength (MIP, MEP), functional capacity (6-Minute Walk Test), cognitive function (MoCA), pain (VAS and SF-MPQ), quality of life (SF-36), physical activity level (IPAQ-SF), sleep quality (PSQI), addiction behavior model (SOCRATES), and health beliefs (Health Belief Model Scale). No therapeutic intervention will be administered.

Primary outcomes

  1. Assessment of Nicotine Dependence

    Time frame: At baseline

    Nicotine dependence will be assessed using the Fagerström Test for Nicotine Dependence (FTND). The test was originally developed by Karl O. Fagerström, and its Turkish validity and reliability study was conducted in 2003. The FTND consists of six items. The total score obtained from participants' responses determines the level of nicotine dependence. Scores of 0-2 indicate very low dependence, 3-4 low dependence, 5 moderate dependence, 6-7 high dependence, and 8-10 very high dependence. This evaluation provides an important criterion for determining the need for intervention related to cigarette dependence.

  2. Maximal Inspiratory Pressure (MIP)

    Time frame: At baseline

    Maximal inspiratory pressure will be measured using the Pony-Fx pulmonary function testing device according to ATS/ERS standards. Assessments will be performed in the seated position with a nose clip. At least three maneuvers will be obtained, and the highest value will be used for analysis. Unit of measure: cmH2O.

  3. Maximal Expiratory Pressure (MEP)

    Time frame: At baseline

    Maximal expiratory pressure will be measured using the Pony-Fx pulmonary function testing device according to ATS/ERS standards. Assessments will be performed in the seated position with a nose clip. At least three maneuvers will be obtained, and the highest value will be used for analysis. Unit of measure: cmH2O.

  4. Assessment of Functional Capacity

    Time frame: At baseline

    Functional capacity will be assessed using the 6-Minute Walk Test (6MWT) in accordance with American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines. Participants will perform the test in a 30-meter corridor. Two tests will be conducted, and the longer walking distance will be used for analysis. Rest periods will be permitted and included in the total test duration. The walked distance will be expressed in meters (m). Predicted walking distance values will be calculated using standard reference equations.

  5. Assessment of Cognitive Functions

    Time frame: At baseline

    Cognitive functions will be evaluated using the Montreal Cognitive Assessment (MoCA). MoCA is a comprehensive screening tool that assesses attention, concentration, memory, language skills, executive functions, visuospatial abilities, abstraction, calculation, and orientation. The total score ranges from 0 to 30, and scores of 21 and above will be considered indicative of normal cognitive function. The Turkish version has established validity and reliability.

  6. Assessment of Pain

    Time frame: At baseline

    Pain will be evaluated using the Short-Form McGill Pain Questionnaire (SF-MPQ) to assess both qualitative and quantitative aspects of pain. The scale consists of three sections. The first section includes 15 descriptors (11 sensory and 4 affective). Participants rate each descriptor from 0 (none) to 3 (severe). The second section evaluates overall pain intensity using a visual comparison scale. The third section assesses present pain intensity on a scale from 0 (no pain) to 5 (unbearable pain). Scores will be analyzed separately as sensory, affective, and total pain scores. The Turkish version has demonstrated validity and reliability.

  7. Assessment of Quality of Life

    Time frame: At baseline

    Quality of life will be assessed using the Short Form-36 (SF-36) Health Survey. This scale evaluates general health status across eight domains: physical functioning, role limitations due to physical problems, social functioning, role limitations due to emotional problems, vitality, pain, mental health, and general health perception. Each domain is scored from 0 to 100, with higher scores indicating better quality of life. The Turkish version has established validity and reliability.

  8. Assessment of Physical Activity Level

    Time frame: At baseline

    Physical activity level will be assessed using the International Physical Activity Questionnaire - Short Form (IPAQ-SF). This questionnaire collects information about walking, moderate-intensity activity, vigorous-intensity activity, and sedentary time during the past seven days. It consists of seven items grouped into four sections.

    Based on participants' responses, weekly physical activity levels will be calculated and classified as low, moderate, or high. Metabolic equivalent (MET) values will be used in the calculation (vigorous activity: 8 METs; moderate activity: 4 METs; walking: 3.3 METs), and weekly MET-minutes will be determined for each activity type.

  9. Assessment of Sleep Quality

    Time frame: At baseline

    Sleep quality will be evaluated using the Pittsburgh Sleep Quality Index (PSQI). The scale consists of 24 items, 19 of which are self-rated and 5 rated by a bed partner or roommate. It includes seven components: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. Each component is scored between 0 and 3, yielding a total score ranging from 0 to 21. Items completed by a partner or roommate are not included in the total score calculation. Lower total scores indicate better sleep quality. The Turkish version has demonstrated acceptable reliability.

  10. Addiction Behavior Model

    Time frame: At baseline

    Addiction behavior will be evaluated using the Stages of Change Questionnaire (SOCRATES). This 19-item self-report scale assesses readiness to change and motivation for treatment. The Turkish version has established validity and reliability.

  11. Assessment of Health Behaviors

    Time frame: At baseline

    Health behaviors will be assessed using the Health Belief Model Scale (HBM). The Health Belief Model is a psychosocial framework developed to understand health-related behaviors. It examines perceived susceptibility, perceived severity, perceived benefits, perceived barriers, self-efficacy, and cues to action. The Health Belief Model Scale is used to measure these perceptions, and adaptations for smoking cessation behavior are available in Turkey.

Study contacts

Contact information is provided by the study sponsor or research team.

Betül Taşpınar, Prof.Dr.

CONTACT

[email protected]

+90 506 680 44 26

Özge Kuşçu, Pt.

CONTACT

[email protected]

+90553 105 86 54

Sponsors and collaborators

Lead sponsor

Izmir Democracy University

Other

Registry information

Official study title

The Relationship Between Nicotine Addiction Level and Respiratory Muscle Strength, Functional Capacity, Cognitive Functions, Pain, Quality of Life, Physical Activity Level, and Sleep Quality

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Mar 16, 2026
Registry last updated
Mar 16, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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