Smoking behavior and addiction are assessed by the Fagerström Test for Nicotine Dependence (FTND), a six-item questionnaire that queries about smoking behaviors, including the number of cigarettes smoked per day and difficulty in refraining from smoking in certain situations [11]. TTFC, the first item of FTND, reflects nicotine dependence and is related to the ability to quit [12]. Most epidemiologic studies take into account cigarettes per day and duration, but there is strong evidence that TTFC provides additional information which may be important in assessing smoking-related disease risk.
