The following is a summary of “Association Between Indices of Thyroid Hormone Resistance and Constipation Prevalence in the US Population: NHANES 2007–2010,” published in the November 2024 issue of Gastroenterology by Li et al.       

Chronic constipation is common and impacts QoL. Hypothyroidism is often implicated, but studies on thyroid hormone resistance (THR) and constipation are limited. 

Researchers conducted a retrospective study to examine the association between THR and constipation. 

They analyzed data from 6354 participants in the National Health and Nutrition Examination Survey (NHANES) 2007–2010. Chronic constipation was defined by a Bristol Stool Form Scale (BSFS) of 1–2 or less than 3 bowel movements weekly, THR was assessed using several indices. Weighted logistic regression (WLR), restricted cubic splines (RCS), subgroup analysis, and sensitivity analysis were applied. 

The results showed that 10% of participants had chronic constipation, with a nonlinear relationship between the Thyroid Feedback Quantile-based Index of Free Thyroxine (TFQIFT4) and constipation, showing inflection points at −0.25 and 0.376. A negative association with constipation was observed in females above a TFQIFT4 value of −0.25 (OR=0.21; 95% CI: 0.10–0.44), but no such association was found in males. 

They concluded that THR, particularly TFQIFT4, was associated with constipation in females, with gender-specific differences observed. Further research is needed to explore the mechanisms involved. 

Source: journals.lww.com/jcge/fulltext/9900/association_between_indices_of_thyroid_hormone.382.aspx