People who smoke their first cigarette within minutes after waking up have much higher levels of cotinine, a by-product of nicotine when processed by the body, than those who wait to smoke, regardless of the number of cigarettes smoked according to the results of a study published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.

"Since cotinine levels appear to reflect the risk of lung cancer, our results suggest that smokers who smoke immediately after waking may be especially at risk for lung cancer," said researcher Joshua E. Muscat, professor of public health sciences at Penn State College of Medicine.

"These people may require a more intensive intervention than other smokers to help them quit smoking on a sustained or permanent basis."

Nicotine levels in the blood can be measured biochemically by the concentration of the metabolite cotinine. Muscat and colleagues conducted a community-based study to examine whether the amount of time to the first cigarette after waking up affects the bodily uptake of nicotine.

This in turn may affect one’s success in quitting smoking and have multiple health effects, such as lung cancer.

"Not all smokers are the same and approaches to smoking reduction may need to account for individual smoking behaviours such as the intensity and frequency of puffing, cravings and physiological symptoms," said Muscat.

"It is unclear why smokers who take their first puff immediately after waking have higher cotinine levels, but this may reflect a more intense pattern of smoking. We need to find out why this is."

The researchers are currently conducting follow-up studies to investigate levels of additional nicotine metabolites that will further confirm this association and help determine the impact of time to first cigarette as a novel risk factor for lung cancer.