Supplementary Material for: Association between 19 Allergens and Chronic Constipation in Adults: NHANES 2005–2006

<b><i>Introduction:</i></b> There are increasing reports of a link between chronic constipation and allergies in children. However, similar epidemiological evidence is limited in the general adult population. Therefore, in this study, we attempted to assess the association between chronic constipation and allergy in adults aged ≥20 years in the USA. <b><i>Methods:</i></b> We established a logistic regression model to test the relationship between chronic constipation and 19 specific immunoglobulin E (sIgE) types in adults aged ≥20 years using large-sample data from the National Health and Nutrition Examination Survey database (2005–2006). The weekly defecation times of the allergic and non-allergic groups were compared using the <i>t</i> test. <b><i>Results:</i></b> We found that sIgE-sensitized participants had a 0.723 lower risk of chronic constipation than the general population (95% confidence interval (CI) = 0.566–0.923). There was a negative association between chronic constipation and sensitizations to peanut (odds ratio (OR) = 0.579, 95% CI = 0.381–0.935), egg (OR = 0.335, 95% CI = 0.134–0.838), dog (OR = 0.723, 95% CI = 0.522–0.965), and cockroach (OR = 0.540, 95% CI = 0.373–0.784). In addition, the frequency of defecation per week increased significantly in people allergic to peanuts and cockroaches (<i>p</i> &lt; 0.05). <b><i>Discussion/Conclusion:</i></b> The results of this study demonstrate an inverse relationship between sIgE sensitization and chronic constipation in adults. However, the specific association mechanism needs to be further studied.