Increased risk of Parkinson disease with diabetes mellitus in a population-based study

This nationwide population-based study investigated the risk of Parkinson disease (PD) in relation to diabetes mellitus (DM) through the National Health Insurance Research Database in Taiwan. A retrospective study was conducted, consisting of 36,294 patients who were newly diagnosed with DM between January 1, 2000 and December 31, 2006 and 108,882 individuals without DM as healthy controls from insurance claims data from Taiwan's National Health Research Institutes Dataset. The subjects were followed up until December 31, 2011 or until the first manifestation of PD. The hazard ratio (HR) of DM for PD incidence was estimated by Cox proportional hazard regression model. Compared with the non-DM cohort, the incidence density rate of PD was 1.36-fold higher in the DM cohort (1.53 vs 2.08 per 1000 person-years) with an adjusted HR of 1.19 (95% confidence interval = 1.08–1.32) after adjusting for age, sex, comorbidities, and medication use. The adjusted HR of PD for DM with a larger magnitude was observed in females (1.29, 1.12–1.49); individuals age 65 years and older (1.20, 1.06–1.35); those without schizophrenia (1.20, 1.08–1.33), bipolar disorder (1.20, 1.08–1.33), hypertension (1.18, 1.06–1.32), hyperlipidemia (1.21, 1.09–1.34), chronic obstructive pulmonary disease (1.19, 1.06–1.32), coronary artery disease (1.22, 1.09–1.36), stroke (1.23, 1.10–1.37), asthma (1.20, 1.08–1.34), flunarizine use (1.21, 1.08–1.35), zolpidem use (1.16, 1.04–1.30), Charlson comorbidity index score of 0 (1.23, 1.08–1.40), and those using metoclopramide (1.35, 1.14–1.60) and zolpidem (1.46, 1.12–1.90). DM increased the risk of PD during a mean follow-up of 7.3 years. Further mechanistic research on the effect of DM on PD is needed.