OBJECTIVES:

Although the endogenous cannabinoid system modulates bowel function, our understanding of the impact of recreational marijuana (MJ) use on bowel motility is limited. This study examines the effect of MJ on self-reported bowel function among a large cohort of US adults.

METHODS:

We identified adults (age: 20–59 years) who completed both the drug use and bowel health questionnaires in the National Health and Nutrition Examination Survey over a 6-year period from 2005 to 2010 (n = 9,645). Constipation and diarrhea were defined according to stool form (Bristol Stool Form Scale) and/or frequency criteria. Adjusted odds ratios (AORs) for likelihood of constipation or diarrhea were estimated in a multinomial logistic model according to MJ use status.

RESULTS:

Overall, constipation prevalence was lower among those with recent MJ use compared with those with past/never use (7.5% vs 10.2%, P = 0.03). Recent MJ use was associated with a 30% decreased odds of constipation (crude odds ratio: 0.71 [0.56–0.98], P = 0.005), which persisted after stepwise adjustment for age and other demographic factors including sex, ethnicity, education, body mass index, and socioeconomic status (AOR: 0.64 [0.49–0.83], P = 0.001); comorbidities, substance use (alcohol, tobacco, heroin, and cocaine), constipating medications, general health condition, rigorous physical activity, and emotional disturbances (AOR: 0.68 [0.48–0.93], P = 0.016); and diet (AOR: 0.68 [0.52–0.89], P = 0.006). There was no association between recent MJ use and diarrhea.

DISCUSSION:

In a nationally representative sample of community-dwelling US adults, recent MJ use was associated with decreased odds of constipation, counter to the known physiologic effects of cannabinoids on colonic motility.