Levels of a tobacco-specific carcinogen were highest among people who smoked the soonest upon waking “regardless of the frequency of smoking,” study author Steven Branstetter said.
The assistant professor of biobehavioural health at Penn State said the reason may be that people who smoke sooner after waking “inhale more deeply and more thoroughly,” he said.
That could explain the higher levels of NNAL — a metabolite of the carcinogen NNK —in their blood, as well as their higher risk of developing oral or lung cancer, he said.
As a result, the timing of that first cigarette “might be an important factor in the identification of high-risk smokers and in the development of interventions targeted toward early-morning smokers.”
Branstetter and his colleague Joshua Muscat, professor of public health sciences, examined data on 1,945 smoking adult participants.
Participants provided urine samples for analysis as well as information about their smoking behaviour, including how soon they typically smoked after waking.
The researchers found that around 32 per cent of the participants they examined smoked their first cigarette of the day within five minutes of waking; 31 per cent smoked within 6 to 30 minutes of waking; 18 per cent smoked within 31 to 60 minutes of waking; and 19 per cent smoked more than one hour after waking.