Brakedal B, et al. - The authors embraced this study to investigate if the use of glitazone drugs was correlated with a lower incidence of Parkinson's disease (PD) among diabetic patients. In populations with diabetes, the use of glitazones was associated with a decreased risk of incident PD. To confirm and understand the role of glitazones in neurodegeneration, further studies were warranted.

• The incidence of PD was compared among individuals with diabetes who used glitazones, with or without metformin, and individuals using only metformin in the Norwegian Prescription Database.
• This database contains all prescription drugs dispensed for the entire Norwegian population.
• During a 10-year period, 94,349 metformin users and 8396 glitazone users were identified.
• The authors compared the incidence of PD in the 2 groups using Cox regression survival analysis, with glitazone exposure as a time-dependent covariate.

• Compared with metformin-only use, glitazone use was correlated with a significantly lower incidence of PD (hazard ratio, 0.72; 95% confidence interval, 0.55-0.94; P = 0.01).