“…Exact matching was performed to match this cohort in a 1:10 fashion to controls without diagnoses of neither PD and related diseases nor OCD before the enrollment on the bases of age (±1 year), sex, enrollment time, medical comorbidities, income level (levels 1-3 per month: ≤15,840 New Taiwan dollars [NTD] or 528 United States dollars [USD], 15,841-25,000 NTD or 528-833 USD, and ≥25,000 NTD or ≥833 USD), and urbanization level of residence (levels 1-5, most to least urbanized), a proxy for healthcare availability in Taiwan (15). Medical comorbidities included cerebrovascular diseases, traumatic brain injury, hypertension, dyslipidemia, and diabetes mellitus because those medical conditions may be related to PD risk (16,17). In addition, Charlson Comorbidity Index (CCI) and all-cause clinical visits were provided for the OCD and the matched-control cohorts.…”