A review of 42 previously published studies concludes that current smokers are twice as likely to develop colon polyps, which sometimes can become cancerous, Reuters reported Feb. 12.

Researcher Edoardo Botteri of the European Institute of Oncology and colleagues said the findings provide "strong evidence" that smoking contributes to both high-risk polyp formation and their progression to cancer. Former smokers also have an elevated risk of developing polyps, but not as high as current smokers, suggesting that people can lower their risk of colon cancer if they stop smoking.

The study did not clarify whether smokers develop polyps at a younger age than nonsmokers.

The study was published in the February 2008 issue of the journal Gastroenterology.