Early morning smokers at more risk of cancer

8th August 2011 --According to two new studies, smokers who take their first puffs soon after they wake up in the morning may be running a greater risk of developing lung and head and neck cancers than those who wait to have their first cigarette of the day.

The results of these studies, published in the American Cancer’s Society’s journal Cancer, may help identify smokers who have a particularly high risk of developing cancer and who would benefit from targeted intervention to reduce this risk.

It’s common knowledge that cigarette smoking increases the risk of developing various types of cancer, but why do some smokers get cancer and others are less at risk? The researchers from Penn State College of Medicine in the US investigated whether nicotine dependence, as characterised by the time taken for a smoker to light up after waking, affects their risk of developing cancer of the lung or head and neck, no matter how often and how long they smoked.

Lung cancer

The lung cancer study included 4,775 cases of lung cancer and 2,835 controls, all of whom were regular cigarette smokers. When compared with those who smoked more than 60 minutes after waking, individuals who had their first cigarette 31 to 60 minutes after waking were 1.31 times more likely to develop lung cancer, and those who smoked within 30 minutes were 1.79 times more likely to develop lung cancer.

Head and neck cancer

The head and neck cancer study included 1,055 people with head and neck cancer and 795 controls, all of whom had a history of cigarette smoking. When compared with those who smoked 60 minutes after waking, individuals who smoked 31 to 60 minutes after waking were 1.42 times more likely to develop head and neck cancer, while those who smoked within 30 minutes were 1.59 times more likely to develop these cancers.

These findings indicate that the need to smoke right after waking in the morning may increase smokers’ risk of getting cancer. "These smokers have higher levels of nicotine and possibly other tobacco toxins in their body, and may be more addicted than smokers who refrain from smoking for half an hour or more," according to Dr Joshua Muscat, one of the authors of the study, in a news release. It may be a combination of genetic and personal factors that cause a higher dependence on nicotine, he says.

A group who would benefit from intervention

Because smokers who light up first thing in the morning are a group at high risk of developing cancer, they would benefit from targeted smoking cessation programmes. The US researchers suggest this could help reduce the negative health effects of tobacco as well as the costs associated with its use.

Reacting to the findings in an emailed statement, Professor Robert West from Cancer Research UK says: "Smokers who light up soon after waking tend to smoke each cigarette more intensively. So the most likely explanation of this finding is that the sooner a smoker lights up, the more smoke is taken into the lungs, and the higher the level of exposure to cancer causing chemicals. This may help estimating levels of tobacco exposure more than just looking at the usual daily cigarette consumption."