In 2025, X. Zhang and a team analyzed 467,200 adults aged 37–73 from the UK Biobank, tracking them for Parkinson’s disease (PD). They defined metabolic syndrome (MetS) as having at least three of: big waist (≥40 inches men, ≥34.6 inches women), high blood pressure, low HDL cholesterol, high triglycerides, or high blood sugar. They checked medical records for 3,222 PD cases.