Lower dietary fibre intake, but not total water consumption, is associated with constipation: a population-based...

Associations between constipation and dietary fibre and water intake, as well as various lifestyle factors, have not been fully evaluated. The present study aimed to investigate associations between fibre and water intake and constipation, as well as other possible risk factors for constipation, in a large adult population.

Data obtained from 14 024 adults aged ≥20 years from three cycles of the National Health and Nutrition Examination Survey (NHANES) 2005-2010, who had completed a bowel health questionnaire, were included in this cross-sectional population-based study. Variables included demographics, lifestyle and dietary factors, comorbidities and laboratory parameters. Logistic regression analyses were performed to determine associations between potential risk factors and constipation.

Among 17 132 participants ≥20 years, 2401 (14%) did not complete bowel health questionnaires and were excluded, along with pregnant women (n = 461) and participants without dietary sample weight on day 1 (n = 246), leaving data from 14 024 participants available for analysis. Multivariate analysis revealed that black race/ethnicity [odds ratio (OR) = 1.380, 95% confidence interval (CI) = 1.054-1.809], a lower than 12th grade education (OR = 1.420, 95% CI = 1.154-1.749) or high school education (OR = 1.339, 95% CI = 1.057-1.697), lower income/poverty ratios (1.3-3.49 versus ≥3.5: OR = 1.261, 95% CI = 1.015-1.567), normal weight (OR = 1.913, 95% CI = 1.534-2.386) or overweight (OR = 1.536, 95% CI = 1.207-1.955), depression (OR = 1.610, 95% CI = 1.119-2.315) and poor teeth (OR = 1.441, 95% CI = 1.100-1.888) were associated with an increased risk for constipation. Lower dietary fibre intake was associated with a greater risk of constipation. Total water consumption was significantly associated an with an increased risk of constipation in univariate analysis, but not in multivariate analysis.

Lower dietary fibre intake, but not poor water consumption, was associated with a greater risk of constipation in US adults.