Age, Gender, Comorbidity, and the MDS-UPDRS: Results from a Population-Based Study

Understanding sources of variation in International Parkinson and Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) scores is essential for planning clinical trials in Parkinson's disease and interpreting studies of mild parkinsonian signs.

We describe the characteristics of the MDS-UPDRS in a population-based sample of individuals without parkinsonism. Multiple linear regression and Spearman's rank correlation coefficients were used to examine potential associations.

Among 194 consecutive individuals without parkinsonism, the mean total MDS-UPDRS score was 12.5 (SD 9.8). Sixty-nine percent (134/193) had motor examination (Part III) scores of 2 or more, 16% (30/194) had scores of 10 or more. Female sex, arthritis or spondylosis, diabetes mellitus, and essential tremor were found to be associated with statistically significant increases in MDS-UPDRS Part III scores. For every 10-year increase in age, the Part III score was greater on average by 2.2 (1.5-2.8).

Elevated MDS-UPDRS scores are common in the general population. The overall burden of motor signs of parkinsonism is especially high in older age groups, in women, and in those with particular comorbidities. Whether this represents evidence of a subclinical neurodegenerative process or the effect of comorbid conditions requires further examination.