The time it takes to reach for the first cigarette of the day may determine risk of lung cancer, according to a recent study.

Researchers found that the "time to first cigarette "of the day is a marker of addiction and may be associated with the risk of getting lung cancer in both heavy and light smokers. Standard markers of nicotine dependency include cigarettes smoked per day, duration of smoking, and cumulative exposure (pack years).

"Assessing [time to first cigarettes] may improve lung cancer risk prediction and could be useful in lung cancer screening and smoking cessation programs," researchers wrote in their study.

For the study, researchers analyzed questionnaire data from the Environment and Genetics in Lung Cancer Etiology (EAGLE) study of current and former smokers in Italy and the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer screening trial in the United States.

In these studies, subjects were asked about their smoking history and habits and to answer the question, "How soon after you wake up do you usually smoke your first cigarette of the day?" The responses were categorized as 5 or fewer, 6-30, 31-60, and more than 60 minutes.

Based on findings from the EAGLE study, which involved more than 3,000 smokers, the risk of lung cancer was statistically significantly higher in those with shorter time to fist cigarette. The association of time to first cigarette with lung cancer risk was stronger in current vs. former smokers and, surprisingly, in lighter vs. heavier smokers but not different between men and women. In analyses of the PLCO study, lung cancer risk increased in a borderline statistically significant trend.

Researchers said their study results support the association of time to first cigarette with lung cancer risk. However, they think more prospective and screening studies are needed.