Association between hypothyroidism and constipation: A cross- sectional study from the PERSIAN Guilan cohort study

Background: Thyroid disorders, particularly hypothyroidism, can affect the movement of the digestive system. The aim of this study was to investigate the association between hypothyroidism and constipation. Methods: In this cross-sectional study that was conducted on the PERSIAN Guilan Cohort Study (PGCS), all individuals between the ages of 35 and 70 years, irrespective of gender, were included. The questionnaires were completed using dedicated online software that included demographic data, clinical characteristics, and nutritional information. Hypothyroidism was defined based on taking levothyroxine medicine as stated by the patient and diagnosis of chronic constipation was based on self-report. Individuals were divided into two groups based on their constipation status and compared with respect to the desired variables. The relationship between hypothyroidism and constipation was examined using logistic regression analysis. Odds ratio (OR) and 95% confidence interval (CI) were calculated. Results: The prevalence of hypothyroidism and constipation were 5.1% and 4.4% respectively, and both were more common in women than in men. In unadjusted model, there was no significant association between hypothyroidism and constipation (OR=1.28, 95% CI: 0.88–1.87, P=0.201). Similar result was obtained in fully adjusted model (OR=1.03, 95% CI: 0.70–1.53, P=0.875). Conclusion: There was no significant association between hypothyroidism and constipation in this study. Since nutrition and the type of fruits and vegetables and the type of substances consumed have an effective role in eliminating constipation, we recommend that these items be considered in future studies.