EFFECTS OF SMOKING ON CENTRAL BLOOD PRESSURE

Abstract

Abstract Objective: Smoking is known to induce systemic vascular damage, leading to cardiovascular diseases. Recent studies demonstrated that central blood pressure has a greater impact on cardiovascular events than brachial blood pressure. We investigated effects of habitual smoking on central systolic blood pressure (CSBP) in the general population. Design and method: A total of 5630 subjects (male = 2622, 51.7 ± 12.0 year-old at baseline), who visited our hospital for a physical check-up at least twice during the last 10 years and underwent CSBP measurement at each visit, were enrolled, and effects of smoking on the average and yearly changes of CSBP (median follow-up 5 years) were analyzed. Brachial blood pressure (oscillometer) and radial artery pressure waveforms (tonometer) were recorded using an automated device, and the pressure corresponding to the second systolic peak of radial pressure waveforms was taken as CSBP (HEM-9000AI, Omron Healthcare, Kyoto). Hypertension was defined as brachial BP > = 140/90mmHg or the use of antihypertensive medications. A yearly change in CSBP was calculated in each subject by linear regression analysis using longitudinal data. Results: The average CSBP during the follow-up was higher in habitual smokers than in non-smokers when analyzed in normotensive (n = 4634, 109.1 ± 11.7 vs. 107.6 ± 12.8 mmHg, p < 0.001) and non-treated hypertensive subjects (n = 91, 150.7 ± 14.8 vs. 142.8 ± 16.7 mmHg, p < 0.05), whereas in hypertensive subjects under medication the average CSBP was lower in smokers than in non-smokers (n = 905, 124.6 ± 12.4 vs. 127.8 ± 13.6 mmHg, p < 0.01). Although smoking status did not affect yearly changes of CSBP in both normotensive (habitual smokers vs. non-smokers; 1.38 ± 6.00 vs. 1.44 ± 6.04 mmHg/year) and treated hypertensive subjects (-0.16 ± 7.08 vs. -0.66 ± 8.24 mmHg/year), the unfavorable effect of smoking on yearly increase of CSBP was found in non-treated hypertensive subjects (4.09 ± 15.1 vs. -0.53 ± 10.3 mmHg/year). Conclusions: Habitual smoking increases CSBP especially in subjects with hypertension, however, antihypertensive medications counteract the unfavorable effects of smoking on CSBP. These results imply a new pathway underlying the development of cardiovascular diseases in smokers. Unfavorable changes in the cardiovascular system caused by smoking may quite slowly progress that short period of observation in the present study could not have detected enhanced yearly increases of CSBP by smoking.