ABSTRACT
BACKGROUND: Although smoking is the major risk factor for atherosclerosis under the age of 40, the smoking rate of adolescent and young adult has been is increasing. In case of young adults, there is no available clinical indices reflecting harmful effects of smoking. The aim of this study was to investigate whether any second derivative of photoplethysmogram (SDPTG) index can be used as a clinical index of acute effects of smoking. METHODS: Twenty smoking and eighteen never-smoking males ages between 20-39 without medical history of atherosclerotic disease nor peripheral vascular diseases were selected for this study. We investigated the life styles and risk factors of atherosclerosis through a questionnaire, laboratory test and physical examination. We measured SDPTG at baseline, 3, 5, 10, 15, and 20 minutes for smokers after smoking and walking and for never-smokers after walking. Repeated measures ANOVA and ANCOVA were used for analysing the changes of SDPTG according to time. RESULTS: The heart rate and blood vessel tension (BVT) were different between the smokers and never-smokers after adjusting age, fasting blood sugar, body mass index, depression, and exercise (P < 0.05, P < 0.05, respectively). In contrast to never-smokers, heart rate of smokers at 3 minutes after smoking was increased for 10.1 per minute (P < 0.001) and higher than never-smokers until 15 minutes (P < 0.05). BVT in smokers was decreased at 3 minutes (P < 0.05) from baseline and lower than never-smokers at 3 minutes (P < 0.05). Differential pulse wave index, stress power, remained blood volume, and the changes of these indices according to time were not significantly different between the two groups. CONCLUSION: BVT and heart rate reflected the acute effect of smoking on blood vessels and could be used to provide motivation to quit smoking and make people more concerned about their own health especially to the young smokers who has no symptoms yet.