Association between weight-adjusted-waist index and bowel habits

Abstract

Obesity has become a global public health issue and is closely related to bowel habits. The Weight-Adjusted-Waist Index (WWI), a new indicator of obesity, provides a more accurate assessment of central obesity. This study aims to investigate the relationship between WWI and bowel habits. The 2005–2010 National Health and Nutrition Examination Survey (NHANES) dataset was used for the cross-sectional survey. Bowel habits were defined by self-report. Multiple logistic regression models were used to test the linear association of WWI with chronic diarrhea and constipation. Fitted smoothed curves and threshold effects analysis were used to characterize nonlinear relationships. Subgroup analyses and interaction tests were used to determine the heterogeneity and stability of the study. This population-based study included 14,238 adults (≥ 20 years). After adjusting for covariates, there was a significant positive association between WWI and chronic diarrhea (OR [95% CI] 1.27 [1.14, 1.41]). There was a non-linear association between WWI and chronic constipation, and we found a breakpoint of 9.77, with a positive correlation on the left side of the breakpoint and no statistical significance on the right side. Subgroup analyses and interaction tests showed stable and consistent results between WWI and bowel habits across the stratification factors. Elevated levels of WWI are associated with an increased risk of chronic diarrhea. A range of WWI < 9.77 is associated with an increased risk of chronic constipation. WWI is a stable valid indicator for assessing intestinal health in U.S. adults, and we should be mindful of the importance of maintaining good levels of body fat in our daily lives to maintain healthy bowel habits.