Abstract
AIMS: The aim of this study was to investigate the relationship between thyroid hormones and chronic constipation in the elderly. Methods: This pilot study was conducted at the Center of Gerontology and Geriatrics, West China Hospital. A total of 267 inpatients aged 60 years or older were enrolled from January 2015 to May 2016. All the patients were evaluated whether or not chronic constipation. Thyroid-stimulating hormone (TSH), triiodothyronine (T3), tetraiodothyronine (T4), free triiodothyronine (FT3), and free tetraiodothyronine (FT4) were detected using radioimmunity. We assessed associations between TSH and other thyroid hormones. Results: Our study included 93 patients (34.83%) with chronic constipation, and 174 patients (65.17%) without chronic constipation. At baseline, Compared with the non-constipation patients, the patients with constipation had significantly lower levels T3 (1.38 ± 0.29 nmol/L vs 1.23 ± 0.38 nmol/L; P = 0.01), and FT3/FT4 ratio (0.26 ± 0.05 vs 0.24 ± 0.06; P =0.04). There was no significant difference in TSH, T4, FT3, and FT4. In the constipation patients, none of the correlations between TSH and T3, T4, FT3, and between TSH and FT4, FT3/FT4 was significant. However, in the non-constipation patients, TSH was significantly correlated with T4 (R = -0.298; P = 0.001) and FT3 (R = 0.473; P = 0.01), and between TSH and FT4, FT3/FT4 ratio was significant. Conclusion: Among hospitalized elderly patients with chronic constipation, there is a decreased T4 to T3 conversion, and abnormal biofeedback regulations in thyroid axis. These changes in thyroid hormone production may contribute to chronic constipation in the elderly.