The effects of dietary selenium intake on specific bowel habits (i.e., constipation or diarrhea) in the general population are not well understood. This study aims to evaluate the associations of selenium intake with the risk of chronic constipation and chronic diarrhea in adults aged ≥ 20 years using data from the 2007-2008 and 2009-2010 continuous National Health and Nutritional Examination Surveys (NHANES) (N = 9585). Chronic constipation and chronic diarrhea were defined by Bristol Stool Form Scale (BSFS) types 1 and 2 and BSFS types 6 and 7 as the "usual or most common stool type," respectively, and frequent laxative users were also defined as having chronic constipation. Dietary selenium intake was obtained from 24-h dietary recall. Multivariable logistic regression models were performed controlling for confounding factors (dietary, lifestyle, psychological, and health conditions). No significant associations between selenium intake and chronic diarrhea were found. However, selenium intake was inversely associated with the risk of chronic constipation. Compared with quartile 1, the multivariate-adjusted ORs (95% CI) of chronic constipation across quartiles 2 to 4 of selenium intake were 0.81 (0.64-1.03), 0.74 (0.58-0.95), and 0.54 (0.33-0.89), respectively. This association was significant among men, but not significant among women in subgroup analyses. Generally, there was an inverse association between selenium intake and chronic constipation in adults that modified by sex.
Keywords: Chronic constipation; Chronic diarrhea; National Health and Nutrition Examination Survey; Selenium.