Light and intermittent smoking carry nearly the same risk for cardiovascular disease as daily heavier smoking. The relationship between the amount of tobacco and cardiovascular mortality is not linear. Low levels of tobacco exposure as in light smoking (4 to 7 cigarettes per day) has about 70% of the effect of smoking more than 20 cigarettes a day. The risks of developing lung cancer for light smokers are somewhat lower than heavier smokers, but women between the ages of 35 and 49 years who smoke 1 to 4 cigarettes per day have 5 times the risk of developing lung cancer and men have 3 times the risk as nonsmokers.
1. Bjartveit K, Tverdal A. Health consequences of smoking 1–4 cigarettes per day. Tob Control. 2005;14:315–320.
2. Pope CA III, et.al. Cardiovascular mortality and exposure to airborne fine particulate matter and cigarette smoke: shape of the exposure-response relationship. Circulation. 2009;120:941–948.