The relationship between thyroid function tests and sleep quality: cross-sectional study

INTRODUCTION: The relationship between sleep and hormones have long been recognized. Studies indicated that sleep quality is one of the major modulatory effects on the endocrine system. In this study, we aimed to assess the serum concentration of thyroid hormones in individuals who suffered from low quality sleep. MATERIAL AND METHODS: Based on the Pittsburgh Sleep Quality Index and ISMA Stress questionnaire, we divided 83 participants into two groups. Forty-one individuals with low quality sleep group and 42 with good quality sleep group, all from the male students of a medical school in Tehran, Iran, participated in this descriptive and cross-sectional study. Then, serum levels of thyroid hormones including free T(3), free T(4), and TSH were assessed and compared between two groups. RESULTS: There were a significant increase in serum levels of FT(4) (p=0.01) and TSH (p=0.02). There were also meaningful correlations between sleep score and stress score (p=0.008) as well as stress score and FT(4) (p=0.03) in the case group. CONCLUSIONS: The current study showed that thyroid function tests (T(4) and TSH) significantly rose in the poor sleep condition. We also found correlations between sleep score, stress score, and FT(4) in the poor sleep condition group that suggest low sleep quality can affect thyroid hormones.