Effects of L-thyroxine on gastric motility and ghrelin in subclinical hypothyroidism: a prospective study.

INTRODUCTION

Overt hypothyroidism affects the gastrointestinal system. Limited data are available regarding gastric motility in subclinical hypothyroidism (SCH).

OBJECTIVE

The aim of this study was to assess gastric motility-related gastric symptoms and levels of ghrelin in patients with SCH compared with those in healthy control subjects and to evaluate the potential effects of l-thyroxine replacement therapy.

METHODS

Twenty premenopausal women with SCH and 20 age- and body mass index-matched healthy control women were enrolled in the study. The gastroparesis cardinal severity index questionnaire was used to reveal gastrointestinal motility changes, and electrogastrographic activities were measured. Fasting and postprandial ghrelin levels at 30, 60, and 120 minutes were determined during a mixed meal test. All tests were repeated after 6 months when patients were in the euthyroid state.

RESULTS

The gastroparesis cardinal severity index score, fasting tachygastria ratio, and postprandial/fasting bradygastria ratio in electrogastrography were higher in patients with SCH compared with control subjects (P = .03, P = .04, and P = .04, respectively). All 3 parameters significantly improved after l-thyroxine replacement therapy (P < .001, P = .005, and P =.02 respectively) reaching levels similar to those of control subjects. Baseline and area under the curve for ghrelin during mixed meal tests did not show a difference between patients with SCH and control subjects and before and after l-thyroxine replacement in SCH.

CONCLUSION

Gastric dysmotility and the resultant upper gastrointestinal symptoms can be observed in SCH, and symptomatology related to dysmotility and parameters appear to be improved with thyroid hormone replacement. Our results also suggest that ghrelin levels in response to a meal are similar between women with SCH and healthy women and that normalization of thyroid function by l-thyroxine does not modulate these levels.