If every cell in your body is replaced roughly in 7 years, why do the affects of smoking and other bad habits still affect people who quit?

Question

If every cell in your body is replaced roughly in 7 years, why do the affects of smoking and other bad habits still affect people who quit?

In: Biology

Answer 1

Somewhat relevant to your question, if you quit smoking by the age of 40 you reduce your risk of dying from a smoking-related illness by 90%. Source: a seminar by Richard Peto quite a few years ago.