Smokers who light up soon after waking may be at especially high risk for lung cancer.
In a new study published in Cancer Epidemiology, Biomarkers & Prevention, people who smoked within five minutes of waking had much higher urine levels of NNAL, a by-product of the carcinogen NNK (which is found only in tobacco), than smokers who waited. This held true even when they smoked the same number of cigarettes per day.
Even relatively small increases in NNAL levels are associated with increased lung cancer risk.
Smokers who crave a cigarette first thing in the morning may be more dependent on nicotine and may inhale more deeply.