Frequent bowel movements a risk factor for diverticulitis

Men and women who move their bowels at least two times daily are at higher risk of developing subsequent diverticulitis, a study reports.

The study used medical history, lifestyle factors, and dietary data from individuals participating in the Nurses’ Health Study (NHS) and Health Professional Follow-up Study (HPFS). There were 5,214 incident cases of diverticulitis recorded over 24 years of follow-up encompassing 1,299,922 person-years in the NHS, and 390 cases documented over 14 years covering 368,661 person-years of follow-up in the HPFS.

Multivariable Cox proportional hazards regression models revealed an inverse association between the frequency of bowel movements and risk of diverticulitis.

In NHS, the risk was 30-percent higher among women with bowel movement frequency of at least two times daily than in those who had once-a-day bowel movements (hazard ratio [HR], 1.30, 95 percent confidence interval [CI], 1.19–1.42). Less frequent bowel movements appeared to have a protective effect (HR, 0.89, 95 percent CI, 0.82–0.95; p<0.0001 for trend).

Results were similar in the HPFS cohort. Compared with once daily, frequent bowel movements upped the risk of diverticulitis (HR, 1.29, 95 percent CI, 1.04–1.59) while less frequent bowel movements lowered the risk (HR, 0.61, 95 percent CI, 0.36–1.03; p=0.003 for trend).

The association between bowel movements and diverticulitis was independent of age, body mass index, physical activity, laxative use, or fibre intake.

More studies are needed to shed light on the potential mechanisms underlying the association.