Background: Bowel movement frequency has been related to a variety of cardiovascular risk factors such as inflammation and metabolism of gut microbiota. However, few studies have examined the relations of bowel movement frequency with risk of coronary heart disease (CHD) and mortality in prospective cohorts.
Objectives: To investigate the prospective associations between bowel movement frequency, incident CHD, and mortality in a large cohort of US women, the Nurses’ Health Study.
Methods: Bowel movement frequency was self-reported at baseline in 1982 by 85,976 women who were free from cardiovascular disease and cancer. Incident CHD including symptomatic nonfatal myocardial infarction or fatal CHD was subsequently identified. Deaths were reported by the next of kin or the postal authorities or identified by searching the National Death Index. Multivariable Cox proportional hazards models were used to assess the associations of bowel movement frequency with risk of CHD, total mortality, and mortality due to cardiovascular disease.
Results: During follow-up, we documented a total of 5,805 incident CHD cases (1982-2010) and 20,972 deaths (1982-2012). After adjustment for potential confounders and CHD risk factors at baseline (age, ethnicity, multivitamin use, aspirin use, family history of heart disease, hypertension, hypercholesterolemia, or diabetes at baseline, menopausal status and postmenopausal hormone therapy use, smoking status, alcohol consumption, physical activity, BMI, dietary fiber intake, and AHEI score), having a bowel movement more than once daily was significantly associated with increased risk of CHD, total mortality, and cardiovascular mortality. As compared with women with bowel movement frequency of once daily (reference), the hazard ratios (HRs) for those with more than once daily were 1.09 (95% confidence interval [CI]: 1.01-1.18) for incident CHD; 1.08 (95% CI: 0.99-1.18) for cardiovascular mortality; and 1.13 (95% CI: 1.08-1.18) for total mortality. Less frequent bowel movements were not significantly related to risk of CHD or mortality. Similar findings were observed in sensitivity analyses that excluded participants who had ulcerative colitis history or excluded those who used laxatives.
Conclusions: Compared to those with daily bowel movements, women with more frequent bowel movements had a modestly increased risk of CHD incidence and total mortality. These associations should be examined in other populations.