Effects of smoking on arterial stiffness and haemodynamics in male adolescents in Lusaka

Abstract

Background: Cigarette smoking causes changes in the cardiovascular system including changes resulting from alterations in peripheral resistance such as increase in blood pressure. Increase in Pulse Wave Velocity (PWV), suggesting an increased arterial stiffness has been demonstrated in white smokers. An increase in plasma catecholamines and an impaired Nitric Oxide production are the likely cause of the endothelial dysfunction. The aim of this study was to determine the effects of smoking on arterial stiffness and haemodynamics in black male adolescents using PWV and Arterial Stiffness Index (ASI) and haemodynamic measurements. Methodology: Twenty-two black, male adolescents; age range 19-25 years, who were active-smokers were included in this observational study. Complior Analyze Unit protocol was used to obtain the carotid-femoral PWV (cfPWV) and the carotid-radial PWV (crPWV) 15 minutes before smoking, and an hour after smoking. The Diasys Ambulatory machine was used to determine blood pressure and heart rate for 15 minutes before, 15 minutes during and the hour after smoking. Results: Smoking caused a significant increase in mean PWV and ASI from their baseline values (cfPWV - 7.9 ± 1.94 m/s, cfASI - 26.1 ± 6.0 m/s, crPWV - 11.0 ± 1.62 m/s and crASI - 22.9 ± 3.52 m/s) to cfPWV- 8.5±1.87 m/s, cfASI - 28.6±6.19 m/s, crPWV- 11.5±1.75 m/s and crASI- 24.3±3.53 m/s. cfPWV and cfASI reverted to baseline 15 minutes post smoking while it took over 45 minutes for crPWV and crASI to return to baseline. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) significantly increased during smoking. SBP increased from 113.5±13.15 mmHg to 127.9±13.80 mmHg and returned to baseline after 30 minutes while DBP increased from 79.5±8.79 mmHg to 85.6±10.92 mmHg, retuning to baseline immediately after smoking. HR had a significant increase during smoking from a baseline of 74.3±13.75 bpm to 95.2 ± 16.72 bpm taking 15 minutes to return to baseline. Conclusion: Smoking causes an acute increase in PWV and ASI in African, male adolescents signifying an increase in arterial stiffness in both the elastic and muscular arteries. Smoking also causes a significant rise in haemodynamics (SBP, DBP and HR), which are indices for risk factors for cardiovascular complications such as stroke and heart failure.