Smoking Soon After Waking Increases Risk Of Lung Cancer
New study from the USA shows that smoking soon after waking increases risk of lung cancer, because the shorter the time between waking and having a first cigarette, no matter how many you smoke a day, the higher is your levels of circulating cotinine, a derivative of nicotine that is made in the body and which has been linked to higher risk of lung cancer.
The scientists said that smoking cessation programs should take into account the time smokers waits before they have their first cigarette of the day because it could make a significant difference to their nicotine uptake.
The leader of the research is Dr Joshua E Muscat, professor of public health sciences at Penn State College of Medicine in Hershey, Pennsylvania. “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 Dr Joshua E Muscat. “These people may require a more intensive intervention than other smokers to help them quit smoking on a sustained or permanent basis.”
The blood concentration of the metabolite cotinine is a nice indicator of how well our organism absorbs nicotine when we smoke cigarettes.
Previous researches have shown there is a wide variation in cotinine levels per cigarette smoked, and the researchers assumed that it depends on how often a smoker smokes, and there might be other nicotine dependence behaviors that affect cotinine levels, such as time to first cigarette after waking. This in turn affects a smoker’s chances of quitting as well as impacting smoker’s health.
There were recruited 252 healthy black and white community-dwelling daily cigarette smokers for the study and examined a number of behaviours that are believed to reflect the urge to smoke. They also measured their plasma and urinary cotinine levels.
The results showed that:
- Among one pack per day smokers, there was a 74-fold difference in plasma cotinine levels: from 16 to 1,180 ng/mL
- There were observed two types of nicotine-dependence: low and high
- The “low” dependent participants smoked their first cigarette more than 30 minutes after waking, and they nearly all smoked 20 or less cigarettes a day. Cotinine levels in the low dependent group increased in line with how many cigarettes they smoked per day.
- The “high” dependent participants smoked their first cigarette of the day within 30 minutes of waking but had a wide range (from 6 to 70) in how many cigarettes they smoked per day. The cotinine levels in the high dependent participants group varied little by cigarette frequency compared with the low dependent group, with a plateau effect appearing for heavy smokers (more than 30 per day).
The conclusion of the research could be transmitted with the words of Dr Joshua E Muscat: “These findings suggest that the time to first cigarette is a strong predictor of nicotine uptake and should be considered in the design of smoking interventions. 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.”
Dr Joshua E Muscat and his team are now trying to find out if time the first cigarette affects levels of other nicotine metabolites. If they find a similar link, then time to first cigarette may become another risk factor for lung cancer.