Cumulative effect of lifetime smoking history on arterial stiffness and subclinical atherosclerosis in patients with arterial hypertension

Abstract

Abstract Introduction Although the effect of smoking status on blood pressure (BP) changes is well known an adverse association between cumulative smoke exposure (by pack-years) and functional and structural changes in arteries of patients with high BP has not been consistently demonstrated. Aim of the study was to explore the contributions of cumulative smoke exposure to the vascular consequences of arterial hypertension. Methods Indices of vascular function and structure including carotid-femoral pulse wave velocity (PWV), augmentation index (AIx) and carotid intima media thickness (cIMT) were measured in 485 adults aged less than 60 years old without a history of cardiovascular disease. The cohort was divided into three groups according to office systolic BP (SBP) and diastolic BP (DBP): normal (SBP <130 and DBP <85 mmHg, n=242), high normal (130≤SBP<140 or DBP 85≤DBP<90mmHg, n=96), and hypertension (SBP≥140 or DBP≥90mmHg, n=147). The cohort was subdivided according to pack-years of smoking history as never smokers (0.0 pack-years), light smokers (<20 pack-years), moderate smokers (20-40 pack-years), and heavy smokers (> 40 pack-years). Results The three BP groups had similar age and metabolic parameters (body mass index, fasting blood glucose and LDL-C). Figure shows PWV, AIx and carotid IMT by smoking exposure, stratified by BP level. The lowest PWV level was observed in never smokers with normal BP; whereas heavy smokers with hypertension exhibited the highest PWV. Also of note, heavy smokers with normal BP exhibited comparable PWV to light and never smokers with hypertension. Furthermore, in smokers with more than 20 pack-years tobacco exposure, PWV was higher among patients with high normal BP compared to subjects with normal BP (all P<0.01). In contrast to the monotonic increases in PWV and AIx by BP and pack-years smoking history, carotid IMT was generally similar among BP groups on the basis of cumulative exposure category. This finding may indicate a plateau in subclinical atherosclerotic burden over cumulative tobacco exposure for all BP categories. Conclusion Tobacco cumulative exposure adversely modify the effect of BP on arterial stiffness. Given that most adults who smoke start before the age 18 years, efforts to promote smoking cessation should continue to target younger adults with high BP.BP, tobacco exposure-vascular changes