Effects of chronic cigarette smoking on vascular function, sympathetic activation and cognitive function

Individuals with a history of cigarette smoking are at an increased risk of developing cardiovascular disease (CVD) and typically perform lower on cognitive performance tests compared with never smokers. Although high blood pressure (BP) is a strong risk factor for the development of CVD, the relation between cigarette smoking and BP remains unclear. Furthermore, large artery stiffness, a predicator of future CVD events is greater among young/middle-aged (Y/MA) current cigarette smokers compared with never smokers. However, besides smoking cessation there are no known treatments to reduce large artery stiffness in Y/MA smokers. Therefore, Chapter 2 of this dissertation will assess the effects of acute sildenafil treatment on large artery stiffness and Chapter 3 will determine the longitudinal association between BP and cigarette smoking. The risk of developing CVD and the accelerated decline in cognitive performance is even more pronounced among older smokers and especially among individuals that have developed chronic obstructive pulmonary disease (COPD). Large artery stiffness is associated with lower cognitive performance among older, chronic smokers with and without COPD, however this relation has not been assessed among individuals with COPD who also have obstructive sleep apnea. Therefore, this association will be assessed in Chapter 4 of this dissertation. Despite the evidence that individuals with a history of smoking have greater large artery stiffness, the mechanisms that contribute to this greater arterial stiffening are unclear. Chapter 5 of this dissertation will explore the contribution of lung hyperinflation on large artery stiffness and sympathetic nerve activation among individuals with COPD.