title: Individual and joint prevalence of three nonmotor symptoms of PD in the US general population.
abstract: BACKGROUND
  Some nonmotor symptoms may precede the clinical diagnosis of Parkinson's disease (PD) by years.
  
  
  METHODS
  We examined the individual and joint prevalence of depression, daytime sleepiness, and infrequent bowel movement among 10,477 participants of the US National Health and Nutrition Examination Surveys 2005-2008.
  
  
  RESULTS
  For all symptoms, the prevalence was higher in women than in men. Importantly, few participants had two or more symptoms: 1.3% at ages 20 to 29, 1.0% at 30 to 39, 1.2% at 40 to 49, 3.5% at 50 to 59, 1.7% at 60 to 69, 1.1% at 70 to 79, and 1.2% at ages 80 years or older in men; the corresponding prevalence in women was 3.1%, 5.2%, 5.7%, 4.1%, 3.1%, 2.3%, and 1.2%, respectively. In both men and women, depression was correlated with infrequent bowel movement and daytime sleepiness, but the latter two were mutually independent.
  
  
  CONCLUSIONS
  The presence of multiple nonmotor symptoms was uncommon in the general population and the prevalence was higher in women than in men.
authors.affiliation: Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA.
authors.forename: Honglei
authors.initials: H
authors.lastname: Chen
authors.forename: Xuemei
authors.initials: X
authors.lastname: Huang
authors.forename: Xuguang
authors.initials: X
authors.lastname: Guo
authors.forename: Shyamal
authors.initials: S
authors.lastname: Peddada
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D003248:Constipation / Q000453:epidemiology*; D003863:Depression / Q000453:epidemiology*; D006970:Disorders of Excessive Somnolence / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000453:epidemiology*; D015995:Prevalence; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: Parkinson's disease; constipation; daytime sleepiness; depression; nonmotor symptoms; prevalence