Colorectal Cancer Risk Elevated in Men and Smokers
Male gender and current smoking are significant risk factors for advanced colorectal neoplasia and colorectal cancer, according to 
two studies published in the June issue of Clinical Gastroenterology and Hepatology.
In one study, Kelvin K.F. Tsoi, M.D., of the Chinese University of Hong Kong, and colleagues conducted a meta-analysis of 28 cohort studies which included 1,463,796 subjects in America, Europe, and Asia who were followed for a median of 13 years. Compared to never smokers, they found that current smokers had an increased risk of colorectal cancer and rectal cancer (relative risks, 1.20 and 1.36, respectively). They also found that male smokers had a higher risk of colorectal cancer than female smokers (relative risks, 1.38 and 1.06, respectively).
In another study, Stephen P. Nguyen, M.D., of the University of California in San Francisco, and colleagues conducted a systematic review and meta-analysis of 17 studies which included 924,932 subjects. Across all age groups from 40 to older than 70 years, they found that men had a significantly higher risk for advanced colorectal neoplasia than women (pooled relative risk estimate, 1.83).
“We believe that the current data are robust enough to support a critical reassessment of current screening guidelines,” Nguyen and colleagues conclude. “The magnitude of the sex-specific differences in the risk for advanced colorectal neoplasia we found, for example, is very similar to that seen between patients with and without a family history of colorectal neoplasia.”
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