title: Secondary causes of restless legs syndrome in older people.
abstract: BACKGROUND
  Secondary causes of restless legs syndrome (RLS) have been reported to be more common in those with late-onset RLS. However, 'late-onset' in previous studies was defined as onset after 45 years.
  
  
  OBJECTIVE
  To determine the prevalence of secondary causes of RLS and the relationship between aetiological factors and age of symptom onset in an older population.
  
  
  METHODS
  Prospective study conducted over a 5-year period.
  
  
  METHODS
  80 consecutive non-related patients diagnosed with RLS.
  
  
  METHODS
  Patients were assessed according to a standard protocol. Age at symptom onset, severity of symptoms, neurological findings and laboratory tests were examined.
  
  
  RESULTS
  Iron deficiency (serum ferritin <50 ng/ml) was present in 22% of patients with onset before 50 years, 39% of those with onset at 50 to 64 years and 58% in those with onset after 64 years (P = 0.009). Clinical neuropathy was also more common in older-onset patients (P = 0.08). Family history was positive in 39%, 23% and 8% of these groups, respectively (P = 0.008).
  
  
  CONCLUSIONS
  Secondary causes of RLS become more common and a positive family history less common with increased age of symptom onset.
authors.affiliation: Department of Geriatric Medicine, Unit 4, Merlin Park Regional Hospital, Galway, Ireland. s.okeeffe@whb.ie
authors.forename: Shaun T
authors.initials: ST
authors.lastname: O'Keeffe
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D018798:Anemia, Iron-Deficiency / Q000150:complications* / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012148:Restless Legs Syndrome / Q000209:etiology*; D012307:Risk Factors