Background and purpose: Cigarette smoking would post threats to physical health. Even though studies suggested that long-term cigarette smoking would lead to cardiovascular diseases, pulmonary diseases, or even cancer development, the smoking population all around the world was still common. Before progressing into the disease stage, cigarette smokers might have presented decreasing exercise capacity, skeletal muscle function, and cardiac autonomic function as early signs of physiological function decline. The purposes of this study are (1) to investigate the difference in exercise capacity, skeletal muscle function, and cardiac autonomic function between smokers and never smokers, and (2) to test the hypothesis that cigarette smoking is an independent factor associated with exercise capacity. Methods: This is a cross-sectional observational study. This study will invite 150 participants from community in Taipei City. The body composition will be analyzed by bioelectrical impedance analysis, and resting heart rate variability will be evaluated by the heart rate variability monitor. Besides, grip strength, exhale carbon monoxide concentration, pulmonary function test, respiratory muscle performance will be measured. Moreover, subject will have to fill up the Fagerström Test for Nicotine Dependence and Seven-Day Physical Activity Recall Questionnaire. Last will be the cardiopulmonary exercise testing. Statistical analyses will be performed by statistical software for social sciences (SPSS) statistical package v.21.0 for Windows. (IBM SPSS Statistics for Windows, Version 21.0. Armonk, NY: IBM Corp.) Between-group comparisons of exercise capacity, skeletal muscle function and heart rate variability parameters will be performed using independent Student's t-test. Pearson's correlation coefficient will be used to test the correlations between outcome parameters. Stepwise regression analysis will be used to examine the independent association between smoking and exercise capacity after controlling for confounders. The α level will be set at 0.05. The results of this study would provide the early effects of cigarette smoking on physical function, and highlight the importance of early detection and intervention.
Study Type
OBSERVATIONAL
Enrollment
52
The subjects should lie in the supine position on a non-conducting surface for 5 min. 4 surface electrodes with cables will be attached to the right hand and ankle of subjects.
After supine quietly for 20 min, a lead I electrocardiogram will be taken for 5 min.
The participants will squeeze the hand dynamometer as hard as possible with the dominant hand. 3 successive measurements will be taken.
Subjects in sitting position, performing 1 inspiration, then exhale to carbon monoxide meter.
Subjects should be in a sitting position with a nose clip, then perform pulmonary function test. Participants should perform at least 3 acceptable attempts, but no more than 8 attempts in total.
Subject will perform both maximal inspiratory pressure and maximal expiratory pressure for 3 times in sitting position with the nose clip.
Fagerström Test for Nicotine Dependence Traditional Chinese version will be adopted. It is a 6-item questionnaire that could help quantify the smoking frequency, amounts, and level of dependence.
Physical activity will be measured by the Chinese Version of the Seven-Day Physical Activity Recall Questionnaire. Participants will need to recall the time (hours) they spent in various leisure activities in the past 7 days.
Bruce protocol as the treadmill evaluation protocol will be adopted for cardiopulmonary exercise testing.
National Taiwan University, College of Medicine, Department of Physical Therapy
Taipei, Zhongzheng, Taiwan
Maximal oxygen uptake
Maximal oxygen uptake, VO2max (ml/kg/min), as an indicator of exercise capacity. Cardiopulmonary exercise testing will be used to evaluate the maximal exercise capacity by a computer-controlled breath-by-breath metabolic measurement system (Carefusion Corporation, Yorba Linda, CA, USA) base on the treadmill. Bruce protocol, which is a graded treadmill evaluation protocol will be adopted.
Time frame: After finishing all the other measurement. The measurement will be lasted 15 minutes.
Skeletal muscle function
Skeletal muscle function will be assessed by measuring the grip strength of the dominant hand using a hand dynamometer (Jamar, Jackson, MI, USA).
Time frame: After finishing heart rate variability and body composition measurement. The measurement will be lasted 5 minutes.
Cardiac autonomic function
Heart rate variability will be measured by HRV monitor (8Z11, Wegene Technology Inc., Taiwan) in this study.
Time frame: After body composition measurement. The measurement will be lasted 20 minutes.
Skeletal muscle mass
Skeletal muscle mass (kilogram, kg) will be measured by a bioelectrical impedance analyzer (BIA). (Maltron BioScan 920, Maltron International Ltd., Esgender, UK). The subjects should lie in the supine position on a non-conducting surface for 5 min. Skeletal muscle mass will be calculated by the equation of Janssen and colleagues.
Time frame: After collecting basic data of subjects. The measurement will be lasted 5-10 minutes.
Exhale carbon monoxide concentration
Exhale carbon monoxide will be measured by the carbon monoxide meter (CO Check+, MD Diagnostics LTD) for current smoking status evaluation.
Time frame: After finishing heart rate variability and body composition measurement. The measurement will be lasted 1-3 minutes.
Forced expiratory volume in one second
Pulmonary function will be measured by a portable MicroLab® Spirometer (CareFusion, Basingstoke, UK). The outcome measure will include: forced expiratory volume in one second (FEV1, unit: liter).
Time frame: The pulmonary function measurement will be lasted 15 minutes.
Forced vital capacity
Pulmonary function will be measured by a portable MicroLab® Spirometer (CareFusion, Basingstoke, UK). The outcome measure will include: forced vital capacity (FVC, unit: liter)
Time frame: The pulmonary function measurement will be lasted 15 minutes.
FEV1/FVC ratio
Pulmonary function will be measured by a portable MicroLab® Spirometer (CareFusion, Basingstoke, UK). The outcome measure will include: FEV1/FVC ratio, which is useful for detecting possible dysfunction of the respiratory system in clinical practice.
Time frame: The pulmonary function measurement will be lasted 15 minutes.
Respiratory muscle function
Maximal inspiratory pressure (PImax, unit: cmH2O) and maximal expiratory pressure (PEmax, unit: cmH2O) will be measured by a respiratory pressure meter, which could represent the respiratory muscle strength.
Time frame: After pulmonary function test measurement. The measurement will be lasted 10 minutes.
Level of nicotine dependence
Fagerström Test for Nicotine Dependence (FTND) Traditional Chinese version will be adopted for quantifying the level of nicotine dependence. FTND is a 6-item questionnaire. The minimum value is 0 points and maximum values is 6 points. The higher score represents the greater nicotine dependence.
Time frame: After respiratory muscle function measurement. The measurement will be lasted 3-5 minutes.
Seven-day physical activity recall questionnaire
Physical activity will be measured by the Chinese Version of the Seven-Day Physical Activity Recall Questionnaire. Participants will need to recall the time (hours) they spent in various leisure activities in the past 7 days. The energy expenditure (kcal/day) = metabolic equivalents (METs)\*time (hour)\*body weight (kg)/7 days.
Time frame: After respiratory muscle function measurement. The measurement will be lasted 3-5 minutes.
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