Smokers often crave a cigarette within minutes of waking, but a new study shows that lighting up immediately may increase their lung cancer risk.
Research published today in the Journal of the National Cancer Institute examined whether lung cancer risk is affected by how soon smokers have their first cigarette: within 5 minutes, from 6 to 30, 31 to 60, or more than 60 minutes after they wake up. The analysis is based on 3249 current or former smokers from a study in Italy; 1812 were patients with lung cancer and 1437 were control participants.
Of the participants with lung cancer, only 16% waited more than an hour for their first cigarette but 28% smoked within 5 minutes after waking. Among controls, about half didn’t smoke within the first hour after they awoke but 10% did so within 5 minutes.
Compared with waiting more than an hour, the risk of developing lung cancer increased by more than 2-fold among those who had their first cigarette either 6 to 30 or 31 to 60 minutes after waking. Among those who smoked within 5 minutes, the risk increased by 3.5-fold.
Increases in risk held up even after the researchers accounted for a number of factors, including sex, how long the participants had been smoking, how many cigarettes they smoked daily, lung tumor tissue structure, and whether or how long ago they had quit.
The researchers also analyzed similar data from a small number of smokers in a US cancer screening study. Results showed an increased lung cancer risk linked with how soon smokers had their first cigarette of the day, but the association was only borderline significant.
The study’s findings have clinical, public health, and research implications, the researchers noted. Having another way to evaluate risk could help improve lung cancer prediction models and the efficient use of spiral computerized tomography screening programs, they wrote.
Adding the time it takes smokers to have their first cigarette of the day to routine patient information on smoking “may also help smokers and clinicians better gauge lung cancer risk and thereby motivate smokers to quit,” the researchers noted.