Latest research published in the New England Journal of Medicine reports that smoking does really cut years off of a person's life. The study was conducted by Prebhat Jha MD, Chinthanie Ramasudnarahettige MSc, Victoria Landsman PhD, Brian Rostron PhD, Michael Thun MD, Robert N. Anderson PhD, Tim McAfee MD, and Richard Peto FRS and found that the death rate due to any cause of current smokers was three times greater than those who had never smoked. This "excess mortality" was found to be due to neoplastic, respiratory, vascular, and other health issues resulting from smoking. Additionally, the life expectancy of current smokers was at least 10 years shorter than those who had never smoked or quit smoking before the age of 40.
The study also concluded that smokers who quit between the ages of 25 to 34 added 10 years to their lives, those who quit between 35 to 44 added 9 years to their lives, and those who quit between the ages of 45 to 54 years added another 6 years to their lives.
The data used for this study was based upon interviews conducted by the U.S. National Health Interview Study including 113,752 women and 88,496 men over the age of 25 from 1997 through 2004.
For more, go here