Risk of Parkinson disease onset in patients with diabetes: A 9-year population-based cohort study with age and sex stratifications

OBJECTIVE - We retrospectively assessed the age- and sex-specific incidence and relative risk of Parkinson disease (PD) in Taiwan's diabetic population. RESEARCH DESIGN AND METHODS - Study cohort included 603,416 diabetic patients and 472,188 nondiabetic control subjects. Incidence rate and relative risk of PD (ICD-9-CM 332.0) were evaluated. RESULTS - The incidence of PD was 3.59 and 2.15 per 10,000 person-years for the diabetic and control group, respectively, representing a covariate adjusted hazard ratio (HR) of 1.61 (95% CI 1.56-1.66), which was substantially reduced to 1.37 (1.32-1.41) after adjusting for medical visits. Diabetes was associated with a significantly elevated risk of PD in all sex and age stratifications except in young women, with the highest HR noted for young men aged 21-40 years (2.10 [1.01-4.42]), followed by women aged 41-60 (2.05 [1.82-2.30]) and >60 years (1.65 [1.58-1.73]). CONCLUSIONS - Diabetes is associated with an increased risk of PD onset in a Chinese population, and the relation is stronger in women and younger patients.