Age of smoking initiation is defined as the age at which a person first uses cigarettes. Age of smoking initiation is an important indicator of health due to increased risks of becoming addicted, difficulties quitting, and the development of tobacco-related health problems the younger a person is when he or she begins smoking .
Examples of health problems associated with early smoking initiation include a higher risk of lung cancer  and, a higher susceptibility to lung damage , among many others. In Canada, out of the population aged 12 and over who reported being either a current smoker or former smoker, the majority of people initiated smoking between the ages of 15 and 19 (50%), followed by those in the 12-14 age range (29%). Eight percent try cigarettes for the first time between the ages of 5 and 11 . Smoking initiation before the age of 13 years of age is especially problematic as it has been linked with significant health risks and premature mortality .