"Happiness is very nice," said Mr. Peto, who was relieved to have finished the study after two decades. "I had some of it myself when I was young."
"Globally, about half of all young men and one in 10 of all young women become smokers and, particularly in developing countries, relatively few quit," Mr. Peto said, in AOL Money. "If they keep smoking, about half will be killed by it. But if they stop before 40, they'll reduce their risk of dying form tobacco by 90 percent."