Effect of lithium maintenance therapy on thyroid and parathyroid function.
OBJECTIVE
To assess changes induced by lithium maintenance therapy on the incidence of thyroid, parathyroid and ion alterations. These were evaluated with respect to the duration of lithium therapy, age, sex, and family history (whether or not the patient had a first-degree relative with thyroid disease).


METHODS
Prospective study.


METHODS
Affective Disorders Clinic at St. Mary's Hospital, Montreal.


METHODS
One hundred and one patients (28 men and 73 women) with bipolar disorder receiving lithium maintenance therapy ranging from 1 year's to 32 years' duration. The control group consisted of 82 patients with no psychiatric or endocrinological diagnoses from the hospital's out-patient clinics.


METHODS
Laboratory analyses of calcium, magnesium and thyroid-stimulating hormone levels performed before beginning lithium therapy and at biannual follow-up.


RESULTS
Hypothyroidism developed in 40 patients, excluding 8 patients who were hypothyroid at baseline. All patients having first-degree relatives affected by thyroid illness had accelerated onset of hypothyroidism (3.7 years after onset of lithium therapy) compared with patients without a family history (8.6 years after onset of lithium therapy). Women over 60 years of age were more often affected by hypothyroidism than women under 60 years of age (34.6% versus 31.9%). Magnesium levels in patients on lithium treatment were unchanged from baseline levels. After lithium treatment, calcium levels were higher than either baseline levels or control levels. Thus, lithium treatment counteracted the decrease in plasma calcium levels associated with aging.


CONCLUSIONS
Familial thyroid illness is a risk factor for hypothyroidism and hypercalcemia during lithium therapy.
Kusalic
M
M
Department of Psychiatry, McGill University, Montreal, Que.
Engelsmann
F
F
D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000097:blood / Q000188:drug therapy; D016022:Case-Control Studies; D005192:Family Health; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000097:blood / Q000139:chemically induced*; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D007037:Hypothyroidism / Q000097:blood / Q000139:chemically induced*; D008094:Lithium / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D010280:Parathyroid Glands / Q000187:drug effects* / Q000378:metabolism; D011446:Prospective Studies; D013961:Thyroid Gland / Q000187:drug effects* / Q000378:metabolism; D013972:Thyrotropin / Q000097:blood / Q000187:drug effects
D013972:Thyrotropin; D008094:Lithium