• Of 162 patients with pernicious anemia whom we studied, 24.1% had clinical thyroid disease; 11.7% were hypothyroid and 8.6% were hyperthyroid. When abnormal serum thyroid-stimulating hormone (TSH) levels were also considered, thyroid disorders existed in 48.3% of 143 patients. Increased or decreased TSH levels as the sole dysfunction occurred in 14.7% and 6.3% of cases, respectively, and were often associated with thyroid antibodies. The high TSH group fits the picture of subclinical hypothyroidism. The nature of the low TSH group remains to be defined. We conclude that TSH screening in patients with pernicious anemia uncovers frequent abnormalities, which are superimposed on a higher coincidence of overt thyroid disease than previously described. Interestingly, also, eight of nine hyperthyroid patients and all seven patients with low TSH levels had blood type O, contrasting significantly with hypothyroid subjects, who more often had blood type A, and with patients without thyroid disorders.
(Arch Intern Med 1982;142:1465-1469)
Carmel R, Spencer CA. Clinical and Subclinical Thyroid Disorders Associated With Pernicious Anemia: Observations on Abnormal Thyroid-Stimulating Hormone Levels and on a Possible Association of Blood Group O With Hyperthyroidism. Arch Intern Med. 1982;142(8):1465–1469. doi:10.1001/archinte.1982.00340210057014
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