A lead series of cohorts has been run by the American Cancer
Society (ACS) which has led U.S. prospective studies documenting the
link between smoking cigarettes and lung cancer from the first study of
over 188,000 men , to the Cancer Prevention Study 1, follow-up
of 1 million men and women and also documenting the benefits
of stopping smoking where after more than one year the risk was lower
than current smokers and took more than 10 years to return to the
risk of never smokers . Subsequent follow-up data informed the
estimates of tobacco smoking to cancer mortality in the USA providing
essential input to the report by Doll and Peto on the potential to
prevent cancer . Further updates of the ACS cohorts refined our
understanding of the burden of tobacco across decades . The
Cancer Prevention Study cohorts have also contributed leadership to
documenting the burden due to overweight and obesity setting
the stage for the International Agency for Research on Cancer report
on this topic and global estimates . Like other cohorts studying