title: Prospective study on the components of metabolic syndrome and the incidence of Parkinson's disease.
abstract: BACKGROUND
  Inconsistent results regarding the association between the components of metabolic syndrome and Parkinson's disease (PD) have been reported. We investigated whether the metabolic syndrome or its components, or serum total cholesterol, predict PD incidence in a prospective cohort study design.
  
  
  METHODS
  The study was based on the Mini-Finland Health Survey including 6641 individuals aged 30-79 and free from PD at baseline (1978-1980). During 30 years of follow-up, 89 incident PD cases occurred.
  
  
  RESULTS
  After adjustment for sociodemographic and lifestyle factors, the relative risk (RR) of PD was 0.50 (95% confidence interval (CI): 0.30, 0.83) for individuals with the metabolic syndrome compared to those without. This association was especially due to elevated serum triglyceride concentration (≥1.7 vs.<1.7 mmol/L, RR = 0.52, 95%CI: 0.30-0.89, P for trend 0.02) and elevated plasma fasting glucose concentration (≥5.6 vs.<5.6 mmol/L, RR = 0.56 0.32, 0.98, P for trend 0.05). Elevated serum triglyceride and plasma fasting glucose concentration predicted lower PD risk even after excluding the first 10 years of follow-up. After this exclusion and further adjustment for other components of the metabolic syndrome, a suggestively increased PD risk was observed in overweight individuals (≥25 kg/m(2) vs.<25 kg/m(2), RR = 1.75, 95%CI: 1.00, 3.07, P for trend 0.22). Blood pressure, serum HDL cholesterol, or serum total cholesterol carried no prediction of PD risk.
  
  
  CONCLUSIONS
  Elevated serum triglyceride and plasma fasting glucose concentrations predict low PD incidence whereas high BMI seems to be suggestively related to an increased PD risk.
authors.affiliation: The Health Monitoring Unit, Department of Health, National Institute for Health and Welfare, P.O. Box 30, FI-00271 Helsinki, Finland. Electronic address: katri.saaksjarvi@thl.fi.
authors.forename: Katri
authors.initials: K
authors.lastname: Sääksjärvi
authors.affiliation: The Health Monitoring Unit, Department of Health, National Institute for Health and Welfare, P.O. Box 30, FI-00271 Helsinki, Finland. Electronic address: paul.knekt@thl.fi.
authors.forename: Paul
authors.initials: P
authors.lastname: Knekt
authors.affiliation: The Chronic Disease Prevention Unit, Department of Health, National Institute for Health and Welfare, P.O. Box 30, FI-00271 Helsinki, Finland. Electronic address: satu.mannisto@thl.fi.
authors.forename: Satu
authors.initials: S
authors.lastname: Männistö
authors.affiliation: Department of Neurology, Helsinki University Central Hospital, P.O. Box 100, FI-00029 HUS, Finland. Electronic address: jukka.lyytinen@hus.fi.
authors.forename: Jukka
authors.initials: J
authors.lastname: Lyytinen
authors.affiliation: The Health Monitoring Unit, Department of Health, National Institute for Health and Welfare, P.O. Box 30, FI-00271 Helsinki, Finland. Electronic address: markku.heliovaara@thl.fi.
authors.forename: Markku
authors.initials: M
authors.lastname: Heliövaara
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D005387:Finland / Q000453:epidemiology; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology*; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D014280:Triglycerides
chemical_list: D001786:Blood Glucose; D014280:Triglycerides
keywords: Biological markers; Cohort studies; Metabolic syndrome; Parkinson's disease; Risk factors