20 cigarettes a day effects How Many Increase Cancer Risk? Even 1 Cigarette Is Harmful Chart: The Effects of Quitting

In this case, tobacco smoking seems to accelerate the speed of a cellular clock that mutates DNA prematurely

Smoking also raises blood pressure, reduces oxygen supply to the heart, and promotes the formation of fatty plaques in the arteries, all of which contribute to the development of heart disease

A study in The BMJ that assessed approaches to smoking cessation found that there was not much difference between the success of people who decided to quit smoking abruptly and those who decided to follow a step-down approach (reducing the number of cigarettes smoked over time), as long as they had committed to a quit date

What About Vaping The use of electronic cigarettes is undoubtedly safer than the use of standard tobacco-based cigarettes

Merchants of doubt: How a handful of scientists obscured the truth on issues from tobacco smoke to global warming (Bloomsbury Publishing USA, 2011)