Association Between the Inflammatory Potential of Diet and Constipation Among Adults in the United States: A Cross-sectional Study.

Objective: To investigate the potential association between Dietary Inflammatory Index (DII) scores and constipation among a sample of adults in the United States.

Methods: This cross-sectional study used data from adult participants in the 2005 to 2010 National Health and Nutrition Examination Survey (ie, "NHANES"). Self-reported information was used to identify cases of constipation. The DII was used to assess inflammatory potential of the diet. Odds ratios (ORs) and corresponding 95% CIs for the association between the DII and constipation were determined using multivariate logistic regression modeling. Stratified analyses explored whether there was effect modification to influence the relationship between DII and constipation.

Results: Of 8272 subjects, 759 reported constipation, and 7513 did not, corresponding to a prevalence of 9.2%. After adjusting for age, gender, race/ethnicity, marital status, education level, smoking status, alcohol consumption, physical activity, body mass index (BMI), cardiovascular diseases (CVD), hypertension, stroke, diabetes, energy intake, carbohydrate intake, and selective serotonin reuptake inhibitor (SSRI) use. Compared with lower DII scores group T1 (-5.28 to ≤0.72), the adjusted OR values for DII scores and constipation in T2 (>0.72 to ≤2.50) and T3 (>2.50 to 5.24) were 1.27 (95% CI: 1.02-1.58, P=0.029) and 1.43(95% CI: 1.14-1.8, P=0.002). Subgroup analyses showed that there were effect modification of gender and physical activity factors on DII scores and constipation.

Conclusions: Results of this cross-sectional study suggest that a higher dietary inflammatory index score was associated with increased risk of constipation after adjustment for confounding in a multivariable analysis. gender and physical activity were found to be an effect modifier of this relationship.