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Hypothyroidism is common in older women treated with lithium
The background of the study. Lithium carbonate
therapy in patients with psychiatric disorders is often associated
with hypothyroidism. In this study, the frequency of thyroid dysfunction
was determined in patients treated with lithium.
How the study was done. Thyroid function was assessed once in 274 patients receiving long-term lithium therapy for bipolar or unipolar disorder, and repeatedly in 57 of these patients. The latter had normal thyroid function when first studied, and were followed prospectively for at least one year. Serum thyrotropin (TSH), free thyroxine (T4), and antithyroid peroxidase (anti-TPO) antibodies were measured in all patients.
The results of the study. Thirty-one of the 274
patients had onset of hypothyroidism during lithium therapy (Table).
The frequency of hypothyroidism was low before approximately 45
years of age in both women and men, and it increased to approximately
50 percent in women over 65 years of age, but only slightly in men.
Among the patients with thyroid dysfunction, 58 percent had high
serum anti-TPO antibody concentrations.
Table. Thyroid Dysfunction among Lithium-Treated Patients |
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Women (n = 159) |
Men (n = 115) |
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Hypothyroidism |
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During lithium therapy |
27 (17%) |
4 (3%) |
|
Before lithium therapy |
5 (3%) |
3 (3%) |
Hyperthyroidism |
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|
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During lithium therapy |
6 (4%) |
2 (2%) |
|
Before lithium therapy |
2 (1%) |
1 (1%) |
Among the patients followed prospectively (mean follow-up, 53 months, 4 of the 33 women (12 percent) had hypothyroidism and 1 (3 percent) hyperthyroidism caused by Graves’ disease (incidence rate of hypothyroidism among the women, 27 per 1000 person-years of follow-up). There were no cases among the 24 men.
The conclusions of the study. Hypothyroidism occurs with increasing frequency with age in women who are treated with lithium.
The original article. Kirov G, Tredget J, John R, Owen MJ, Lazarus JH. A cross-sectional and a prospective study of thyroid disorders in lithium-treated patients. J Affect Disord 2005;87:313-7.
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| Thyroid Digest Index | | | November 2005 Thyroid Digest |
