Elevated plasma homocysteine level in patients with Parkinson disease: motor, affective, and cognitive associations.
BACKGROUND
An elevated plasma homocysteine (Hcy) level has been prospectively associated with an increased risk of vascular and degenerative dementias. An Hcy elevation is prevalent in patients with Parkinson disease (PD) in part because levodopa metabolism produces Hcy. The clinical relevance of an elevated Hcy level in patients with PD is unknown.


OBJECTIVE
To determine if hyperhomocysteinemia in patients with PD is associated with depression or with cognitive or physical impairments.


METHODS
Ninety-seven people with a mean (SD) PD duration of 3.6 (1.6) years completed the Beck Depression Inventory, a battery of 11 cognitive tests, and the motor and function components of the Unified Parkinson's Disease Rating Scale. Normalized scores for the affective, cognitive, and physical measures were compared between those with a normal Hcy level (n = 66) and those with hyperhomocysteinemia (n = 31) (Hcy level, >1.89 mg/L [>14 micro mol/L]), controlling for age, sex, disease duration, and treatment.


RESULTS
Subjects with an elevated Hcy level were slightly older (68 vs 62 years), but had similar plasma concentrations of vitamin B(12) and folate. Hyperhomocysteinemic patients were more depressed (P =.02) and had worse cognition (P<.01), but the physical measure did not differ.


CONCLUSIONS
Patients with PD and hyperhomocysteinemia are more likely to be depressed and to perform worse on neuropsychometric tasks compared with normohomocysteinemic patients. Further research is warranted to see if hyperhomocysteinemia is a reversible risk factor for neuropsychiatric burden in patients with PD.
O'Suilleabhain
Padraig E
PE
Department of Neurology, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA. Padraig.osuilleabhain@UTSouthwestern.edu
Sung
Victor
V
Hernandez
Carlos
C
Lacritz
Laura
L
Dewey
Richard B
RB
Bottiglieri
Teodoro
T
Diaz-Arrastia
Ramon
R
D000368:Aged; D003072:Cognition Disorders / Q000097:blood* / Q000523:psychology; D003863:Depression / Q000097:blood / Q000523:psychology; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019964:Mood Disorders / Q000097:blood* / Q000523:psychology; D019957:Motor Skills Disorders / Q000097:blood / Q000523:psychology; D010300:Parkinson Disease / Q000097:blood* / Q000523:psychology; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data
D006710:Homocysteine