Serum urate and probability of dopaminergic deficit in early “Parkinson's disease”§

Authors


  • Funding agencies: The present study was supported by the NIH (R01NS061858, K24NS060991), DoD (W81XWH-06-1-0679), and RJG Foundation.

  • Relevant conflicts of interest/financial disclosures: The present study is a secondary analysis of the database of a clinical trial PRECEPT, which was sponsored by Cephalon, Inc. (Frazer, PA), and H. Lundbeck A/S (Copenhagen, Denmark). Dr. Ira Shoulson had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Dr. Kenneth Marek is a consultant/AD board member for GE Healthcare, Alseres, EMD Serono, Lilly, Bayer Healthcare, Sanofi, and Biogen and has an ownership interest in Molecular NeuroImaging, LLC. Dr. John Seibyl is a consultant/AD board member for Bayer Healthcare, GE Healthcare, and Neurologica and has an equity interest in Molecular NeuroImaging, LLC.

  • §

    Full financial disclosures and author roles may be found in the online version of this article.

Abstract

The objective of this study was to investigate whether higher levels of urate, an antioxidant linked to a lower likelihood of developing Parkinson's disease, is also a predictor of having a dopamine transporter brain scan without evidence of dopaminergic deficit. In a cross-sectional study of 797 mildly affected, untreated parkinsonian subjects diagnosed with early Parkinson's disease in the Parkinson Research Examination of CEP-1347 Trial, we investigated the relationship at baseline between serum urate and striatal dopamine transporter density, determined by single-photon emission computed tomography of iodine-123-labeled 2-β-carboxymethoxy-3-β-(4-iodophenyl)tropane uptake. A scan without evidence of dopaminergic deficit was defined as lowest putamen iodine-123-labeled 2-β-carboxymethoxy-3-β-(4-iodophenyl)tropane > 80% age-expected putamen dopamine transporter density. The odds of having a scan without evidence of dopaminergic deficit rose across increasing quintiles of urate level, with an age- and sex-adjusted odds ratio of 3.2 comparing the highest to the lowest urate quintile (95% confidence interval, 1.5–7.2; P for trend = .0003), and remained significant after adjusting for potential confounding factors. The association was significant in men but not women, regardless of whether common or sex-specific quintiles of urate were used. Higher levels of urate were associated with a greater likelihood of a scan without evidence of dopaminergic deficit among subjects with early untreated parkinsonism in the Parkinson Research Examination of CEP-1347 Trial. The findings support the diagnostic utility of urate in combination with other determinants. © 2011 Movement Disorder Society

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