OBJECTIVES:

This study determined the life extension obtained from stopping smoking at various ages.

METHODS:

We estimated the relation between smoking and mortality among 877,243 respondents to the Cancer Prevention Study II. These estimates were applied to the 1990 US census population to examine the longevity benefits of smoking cessation.

RESULTS:

Life expectancy among smokers who quit at age 35 exceeded that of continuing smokers by 6.9 to 8.5 years for men and 6.1 to 7.7 years for women. Smokers who quit at younger ages realized greater life extensions. However, even those who quit much later in life gained some benefits: among smokers who quit at age 65 years, men gained 1.4 to 2.0 years of life, and women gained 2.7 to 3.7 years.

CONCLUSIONS:

Stopping smoking as early as possible is important, but cessation at any age provides meaningful life extensions.