Explanation of male excess risk of advanced colorectal neoplasms by known risk factors

A study among 15,985 participants of screening colonoscopy aged 55-79 years in Germany found that in age-adjusted comparisons, men had a twofold risk fo advanced neoplasia (AN, i.e. CRC or advanced adenoma) compared to women (OR 1.98; 95% CI 1.79-2.19). After adjustment for medical, lifestyle, and dietary factors the OR was reduced to 1.52 (95% CI 1.30-1.77), suggesting that these factors accounted for 47% of male excess risk. Male excess risk increased from proximal colon (age-adjusted OR 1.63) to distal colon (2.13) and rectum (2.36) with proportion of excess risk explained by covariates being lower for AN in the rectum (26%) than in the proximal (52%) or distal colon (46%). The authors conclude that most of male excess risk remains to be explored by further research.