Study finds stronger nicotine dependency associated with higher risk of lung cancer

People who are highly addicted to nicotine -- those who smoke their first cigarette within five minutes after awakening -- are at higher risk of developing lung cancer than those who wait for an hour or more to smoke. Researchers at NCI found this simple measure of nicotine dependency improved lung cancer risk prediction beyond standard smoking measures, such as cigarettes per day, age, gender, history of chronic obstructive pulmonary disease and other lung cancer risk factors. The results of this study were published online in the Journal of the National Cancer Institute, June 19, 2014.

Neil E. Caporaso, M.D., senior investigator, and Fangyi Gu, M.Med., Sc.D., postdoctoral fellow, Genetic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, NCI, and their colleagues, analyzed data from about 1,800 lung cancer patients and 1,400 people without cancer from five cities in the Lombardy region in Italy. The researchers observed that people who had smoked their first cigarette within five minutes of waking up had more than three times the risk of lung cancer compared with those who waited longer than an hour before smoking their first cigarette of the day, after taking into account other smoking characteristics, age and gender. The increased risks were observed for each category of cigarette per day, as well as each category of smoking history. Assessing time to a first cigarette may help clinicians quickly assess lung cancer risk. The findings underscore the need for even light smokers to quit, because even light smokers who are, or who become dependent smokers, can be at substantial risk for developing lung cancer. The researchers plan to investigate the effect of nicotine addiction on risk for other health outcomes in future studies.