Risk factors of thyroid abnormalities in bipolar patients receiving lithium: a case control study.
BACKGROUND
Lithium-induced thyroid abnormalities have been documented in many studies. They may occur despite normal plasma lithium levels. The objectives of this study were: 1) to determine possible relationship between lithium ratio, defined as erythrocyte lithium concentrations divided by plasma lithium concentrations, and thyroid abnormalities in bipolar patients receiving lithium and 2) to find other possible risk factors for developing thyroid abnormalities in the subjects.


METHODS
Sixty-eight bipolar patients receiving lithium therapy were enrolled in a cross-sectional evaluation of thyroid function test and thyroid size. Patients were divided into two groups based on their thyroid function tests and thyroid sizes. Erythrocyte and plasma lithium concentrations were determined by atomic absorption spectrometry for each patient. Lithium ratio was then calculated.


RESULTS
No significant differences were found between age, positive family history of affective disorder, plasma lithium concentration, erythrocyte lithium concentration, and lithium ratio comparing the two groups. Thyroid abnormalities was significantly higher in women than in men (p < 0.05).


CONCLUSIONS
Lithium ratio does not appear to have a predictive role for thyroidal side effects of lithium therapy. Female gender was the main risk factor. We suggest more frequent thyroid evaluation of bipolar women who are treated with lithium.
Ahmadi-Abhari
Seyed-Ali
SA
Department of Psychiatry, Roozbeh Academic and Referral Psychiatric Center. ahmadiab@sina.tums.ac.ir
Ghaeli
Padideh
P
Fahimi
Fanak
F
Esfahanian
Fatemeh
F
Farsam
Hasan
H
Dehpour
Ahmad Reza
AR
Jahanzad
Issa
I
Hatmi
Zinat-Nadya
ZN
Dashti
Simin
S
D000328:Adult; D001714:Bipolar Disorder / Q000097:blood / Q000188:drug therapy*; D016022:Case-Control Studies; D004912:Erythrocytes / Q000737:chemistry; D005260:Female; D006801:Humans; D008094:Lithium / Q000009:adverse effects* / Q000097:blood / Q000627:therapeutic use; D008297:Male; D012307:Risk Factors; D012737:Sex Factors; D013054:Spectrophotometry, Atomic; D013959:Thyroid Diseases / Q000097:blood / Q000139:chemically induced* / Q000453:epidemiology; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000033:anatomy & histology / Q000187:drug effects
D008094:Lithium