Secondhand smoke exposure and cardiovascular disease

Exposure to secondhand tobacco smoke (SHS) is associated with an increased risk of coronary heart disease (CHD) among nonsmokers, which has been estimated to be 20% to 30%. SHS may also increase the risk of stroke; however, the link is equivocal compared with that for CHD. In addition, data from clinical and animal studies support the biologic plausibility of the association between SHS exposure and CHD. Recent experimental evidence has provided further insights into the pathophysiology of the cardiovascular damage associated with SHS exposure. Specifically, it has become clear that short-term, intense exposure to SHS may function as an important trigger of clinical manifestations of CHD via multiple mechanisms such as endothelial dysfunction, platelet activation, oxidative stress, inflammation, and alterations of the autonomic nervous system. This notion is further supported by recent studies suggesting that the risk of CHD associated with SHS exposure is likely to be reduced in the absence of high levels of recent exposure to SHS.