Chronic constipation is negatively associated with colonic diverticula

Constipation has been considered the key risk factor for diverticulosis occurrence, but the underlying mechanism is unclear. We investigated the factors associated with diverticulosis, focusing on the association of constipation severity with the localization and number of diverticula.
We analyzed consecutive patients who underwent colonoscopy between March and December 2019. Chronic constipation was diagnosed as constipation meeting Rome IV criteria or as that requiring laxative therapy for more than 6 months. The degree of constipation was scored using the Constipation Scoring System (CSS).
We assessed 1014 patients. Multivariate analysis revealed that age, alcohol consumption, and hypertension were positively associated with diverticulosis, whereas chronic constipation was negatively associated with diverticulosis (odds ratio [OR] = 0.74; 95% confidence interval [CI], 0.55–0.99). When assessed according to the location of diverticula, right-sided diverticula were significantly associated with a lower incidence of constipation (OR = 0.94; 95% CI, 0.89–0.98), whereas neither left-sided nor bilateral diverticula was associated with constipation. This negative association of diverticula with constipation was stronger in patients with a high CSS score. In stratified analysis, the number of diverticula decreased with increasing degree of constipation (p for trend <.01), and a high CSS score was associated with a decreased prevalence of ≥3 diverticula (OR = 0.64; 95% CI, 0.44–0.99).
Chronic constipation was negatively associated with colonic diverticulosis. The association increased with the degree of constipation and was strong only in cases with right-sided diverticula and those with ≥3 diverticula.