Association Between Dietary Phosphorus Intake and Chronic Constipation in Adults: Evidence from the National Health and Nutrition Examination Survey

Background: Several studies suggest a link between micronutrients and constipation. However, the relationship between constipation and phosphorus has rarely been examined. Consequently, the main aim of this study was to investigate the link between changes in the prevalence of chronic constipation and changes in dietary phosphorus intake among adults in the NHANES (National Health and Nutritional Examination Survey). Methods: Data were extracted from the NHANES database from 2005–2010. In total, after inclusion and exclusion, 13 948 people were included in the analysis. Dietary information was collected using the respondents’ 24-hour dietary records. We conducted several multiple logistic regression analyses to examine the correlation between phosphorus intake and poor bowel movement. Results: After multi-variate adjustment in model Ⅲ, there was a statistically significant association between chronic constipation and each additional 0.1 g intake of dietary phosphorus (odds ratio (OR), 0.97; 95% confidence interval (CI), 0.95, 1.00; P=0.034 for stool consistency vs OR, 0.94; 95% CI, 0.90, 0.99; P=0.027 for stool frequency). After multi-variate adjustment in model Ⅲ, OR values and 95% CI from the second to fourth quartiles compared to the first quartile (reference group) were 0.92(0.66, 1.27), 0.73(0.47, 1.13), and 0.39(0.20, 0.76), respectively. Conclusions: This study revealed a negative correlation between phosphorus intake and chronic constipation. Further studies in different settings should be considered to verify these findings.