Lead author Edoardo Botteri of the European Institute of Oncology in Milan, Italy, performed the analysis of 42 independent observational studies.

Senior author Dr. Albert B. Lowenfels of New York Medical College in Valhalla, N.Y., said the meta-analysis showed smokers had a 13 percent increased risk of polyps for every additional 10 pack-years smoked in comparison to people who never smoked.

Lowenfels said an individual who smoked one pack of cigarettes per day for 50 years or two packs a day for 25 years had almost twice the probability for developing colorectal polyps compared to an individual who never smoked.

"While the harmful health effects of tobacco smoking are well known, smoking has not been considered so far in the stratification of patients for CRC screening," Lowenfels said in a statement. "Our findings could support lowering the recommended age for smokers to receive colorectal cancer screening."