Cancer Society lists cigarettes too fat alcohol as the top 3
https://www.dailymail.co.uk/health/article-13623683/study-cancers-linked-factors-cigarettes.html
“ According to a new report, which was published the American Cancer Society, four in 10 cancer cases and nearly half of cancer deaths in Americans over 30 are linked to smoking cigarettes, being overweight, using alcohol, being inactive, eating a poor diet and getting too much sun. ”