Douglas K. Rex, MD

Clinicians should feel confident in communicating this message to patients who inquire.

Gastroenterologists are often asked whether constipation is a risk factor for colorectal cancer. In the current meta-analysis, investigators analyzed data from cross-sectional surveys, cohort studies, and case-control studies that evaluated the possible association between constipation and colorectal cancer.

Twenty-eight studies were considered eligible, including 8 cross-sectional, 3 cohort, and 17 case-control studies. In the cross-sectional surveys comprising 8866 patients who underwent diagnostic colonoscopy for symptoms, a primary indication of constipation versus other indications for colonoscopy was associated with a lower prevalence of colorectal cancer (pooled odds ratio, 0.56; 95% confidence interval, 0.36–0.89). In the three cohort studies comprising 189,038 patients, the pooled odds ratio for colorectal cancer in constipated patients versus non-constipated patients was 0.80 (95% CI, 0.61–1.04). In the 17 case-control studies comprising 62,594 patients, the pooled odds ratio for constipation in patients with versus without colorectal cancer was 1.68 (95% CI, 1.29–2.18); however, significant heterogeneity between studies was observed, and possible publication bias was a concern.

Citation(s):

Power AM et al. Association between constipation and colorectal cancer: Systematic review and meta-analysis of observational studies. Am J Gastroenterol 2013 Jun; 108:894.