Chronic constipation not a risk factor for later colorectal cancer

Individuals with chronic constipation do not seem to be at increased risk of developing subsequent colorectal cancer (CRC) as compared with their peers who do not have the gastrointestinal condition, as reported in a study.

The nationwide case-control study involved 41,299 patients with CRC diagnosed by colorectal biopsy in Sweden and 203,181 age- and sex-matched controls from the general population. Researchers used logistic regression to compare the likelihood of earlier chronic constipation (defined as ≥2 laxative prescriptions in the Prescribed Drug Register with ≥6 months between first-last prescription) between CRC patients and controls.

The odds of earlier constipation were also compared between CRC patients and sibling comparators in a separate analysis, as was the earlier risk of having an inpatient/outpatient specialty diagnosis of chronic constipation prior to CRC.

In the patient cohort, 3,943 met the criteria for chronic constipation prior to CRC. The crude proportion of chronic constipation was slightly higher in CRC patients than in controls (9.5 percent vs 8.8 percent).

Multivariable logistic regression analysis revealed a modest association between chronic constipation and later CRC (odds ratio [OR], 1.10, 95 percent confidence interval [CI], 1.06–1.14), but this association disappeared when sibling comparators were used to control for residual confounding (OR, 1.04, 95 percent CI, 0.97–1.13).

A sensitivity analysis of 126,650 CRC patients diagnosed 1989–2016 showed no association between CRC and the odds of earlier chronic constipation diagnosed in inpatient/outpatient specialty clinics (OR, 0.88, 95 percent CI, 0.75–1.04).