SLC6A3 and Parkinson disease: As for early-stage PD patients, we similarly found that lower DAT levels in the caudate and putamen were associated with a higher NLR (β = −0.41, p = 0.002 and β = −0.41, p = 0.002, respectively) and a lower lymphocyte count (β = 0.30, p = 0.028 and β = 0.27, p = 0.048, respectively) in the univariate linear regression models.