title: The natural history of insomnia in the Ibadan study of ageing.
abstract: OBJECTIVE
  To determine the incidence and risk factors for insomnia among an under-studied population of elderly persons in Sub-Saharan Africa.
  
  
  METHODS
  Eight contiguous predominantly Yoruba-speaking states in south-west and north-central Nigeria representing about 22% of the national population.
  
  
  METHODS
  1307 elderly community-dwelling persons, aged 65 years and older.
  
  
  METHODS
  Face-to-face assessment with the Composite International Diagnostic Interview, version 3 (CIDI.3) in 2007 and 12 months later in 2008 to determine the occurrence and risk factors of incident and persistent insomnia, defined as syndrome or symptom.
  
  
  RESULTS
  The incidence of insomnia syndrome in 2008 at 12 months was 7.97% (95% CI, 6.60-9.60), while that of insomnia symptom was 25.68% (22.68-28.66). Females were at elevated risk for both syndrome and symptom. Among persons with insomnia symptom or syndrome at the baseline, 47.36% (95% CI 43.07-51.68) continued to have it one year later. Decreasing economic status was associated with increasing incidence of insomnia. Persons with chronic medical conditions at baseline were at increased risk for new onset of insomnia. Compared to persons with the lowest body mass index (BMI) (< 18.5), those with higher BMI were at elevated risk for persistence of their insomnia, with those in the obese range (≥ 30) having a 4-fold risk.
  
  
  CONCLUSIONS
  There is a high incidence and chronicity of insomnia in this elderly population. Persons with chronic health conditions are particularly at risk of new onset as well as persistence of insomnia.
authors: Department of Psychiatry, University of Ibadan, University College Hospital, Ibadan, Nigeria. ogureje@comui.edu.ng
authors: Oye
authors: O
authors: Gureje
authors: Bibilola Damilola
authors: BD
authors: Oladeji
authors: Taiwo
authors: T
authors: Abiona
authors: Victor
authors: V
authors: Makanjuola
authors: Oluyomi
authors: O
authors: Esan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D015992:Body Mass Index; D002908:Chronic Disease / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009549:Nigeria / Q000453:epidemiology; D012307:Risk Factors; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology*; D012923:Social Class