Correlation between thyroid hormones and the need for reduced duration of sleep for patients with bipolar disorder

Objective To explore the correlation between the serum thyroid hormone level and the need for reduced duration of sleep for patients with bipolar disorder (BPD). Methods One hundred and twenty two BPD patients were assigned to two groups on the basis of whether the duration of sleep needed to be reduced. Demographic characteristics and thyroid hormone level were compared between two groups. Spearman[whitesquare]s analysis was used to analyze the correlation between the thyroid hormone level and clinical symptoms for two groups. Logistic regression analysis was employed to assess risk factors for the duration of sleep needed to be reduced. Results Compared with patients whose duration of sleep did not need to be reduced, patients whose duration of sleep needed to be reduced had a lower serum thyroid stimulating hormone (TSH) level [(2.46+ or -1.74) mU/L vs (3.47+ or -2.65) mU/L] and a higher tetraiodothyronine (T4) level [(90.91+ or -31.59) nmol/L vs (76.80+ or -38.55) nmol/L]. The differences were statistical