Even healthy-looking smokers have early cell damage which destroys necessary genetic programming

However, researchers at Weill Cornell Medical College have found that even smokers who seem healthy have damaged airway cells, with characteristics similar to cells found in aggressive lung cancer.

http://www.sciencedaily.com/releases/2013/07/130716102056.htm?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily%2Fhealth_medicine%2Fsmoking+%28ScienceDaily%3A+Health+%26+Medicine+News+--+Smoking%29