how do cigarettes affect your health Why smoking is a harmful habit Smoking and Your Heart -

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[Los Angeles: Warner Brothers, 1942]

[26] on the other hand, only examined current e-cigarette use, without accounting for prior smoking history: had there been a significant association between e-cigarette use and onset of respiratory symptoms, it could be due to prior cigarette smoking, in which case adjusting for pack-years would be necessary (though not necessarily sufficient) to account for this [14]

For the fourth year in a row, e-cigarettes are the most commonly used tobacco product among both middle and high school students, while slightly more high school students now smoke cigars than cigarettes