Smokers who have their first cigarette sooner after waking are at higher risk for lung cancer, researchers at Pennsylvania State University found. Those who smoke immediately after waking have higher blood levels of NNAL, a breakdown product of a carcinogen present in tobacco, compared to those who smoke their first cigarette later in the day. The results hold even for those who do not smoke more cigarettes overall. The researchers suggest that smoking soon after waking may reflect greater tobacco dependence, which could lead those smokers to inhale more deeply and absorb more carcinogens. Based on these findings, some future anti-smoking interventions may focus on early-morning, high-risk smokers. Research paper: