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.