Quitting by 30 'cuts female smokers' risk of early death'
27 October 2012 Last updated at 13:04 BST
Women who give up smoking by the age of 30 will almost completely reduce the risks of dying young from tobacco-related diseases, according to research published in the Lancet.
The study of 1.2 million women suggests that those who stopped smoking by 40 died a year younger than non-smokers and those who stopped by 30 lost, on average, a month of life.
Health experts have warned that this was not a licence for the young to smoke.
Branwen Jeffreys reports.