Thyroid function and autoimmunity in Parkinson's disease: a study of 101 patients

Thyroid disease is the endocrine dysfunction most frequently reported in as sociation with idiopathic Parkinson's disease (PD). The aim of this study w as to assess thyroid autoimmunity and function in PD, and to verify the eff ect of long term L-dopa and/or dopamine therapy on thyroid function. We studied 101 consecutive PD outpatients and seventy age- and sex-matched neurological non-PD patients as controls. They were evaluated for free thyr oid hormones, TSH and thyroid autoantibodies. No significant difference in the prevalence of thyroid autoimmunity and dysfunction was found between PD patients and neurological controls (10.8% in PD patients vs 10% in neurolo gical controls). Further, treatment with L-dopa and/or dopaminergic drugs a nd the stage of Parkinson's disease did not affect thyroid function. In conclusion, the prevalence of thyroid autoimmunity in Pn patients appear ed similar to that as described in the general population, though thyroid d ysfunction was observed in over than 10% of PD patients. Indeed, neurologis ts should be alerted to the possible complications arising from thyroid dys function in Parkinson's disease, but thyroid function tests should be perfo rmed only when justified on clinical grounds. (C) 1999 Published by Elsevie r Science Ltd. All rights reserved.