SLC6A3 and Parkinson disease: After excluding factors strongly correlated to each other and including only strictly significant factors (at the p < 0.005 level) in a multivariable model, older age at baseline, prevalent mild cognitive impairment, higher PIGD score, hyposmia, reduced DAT uptake in the caudate, and an inflammatory reaction (leukocytosis) in the CSF were independent clinical and biomarker predictors of reduced survival in PD.