title: Insomnia, depression, and physical disorders in late life: a 2-year longitudinal community study in Koreans.
abstract: OBJECTIVE
  To investigate prevalence, incidence, and persistence of insomnia, and their bidirectional longitudinal associations with depression and physical disorders.
  
  
  METHODS
  A community based longitudinal study.
  
  
  METHODS
  Elders living in private households in South Korea.
  
  
  METHODS
  1204 people > or = 65 years of age were evaluated at baseline; 909 of them (75%) were re-interviewed after 2 years.
  
  
  RESULTS
  Insomnia was defined as difficulty in initiation or maintenance of sleep > or = 3 nights per week over the last month. Diagnosis of depression (Geriatric Mental State) and number of physical disorders were ascertained. Sociodemographic and clinical covariates included age, gender, education, housing, past occupation, current employment, living area, life events, social deficit, physical activity, cognitive impairment, anxiety, and daily drinking. Of those (27%) with insomnia at baseline, 40% had insomnia at follow-up. Of those without insomnia at baseline, 23% had insomnia at follow-up. Baseline depression was significantly associated with prevalence and incidence of insomnia. Baseline number of physical disorders was significantly associated with prevalence, incidence, and persistence of insomnia. Baseline insomnia was independently associated with incident depression and an increase in reported physical disorders.
  
  
  CONCLUSIONS
  Insomnia was common and often persistent in this population. Insomnia was closely and reciprocally related to depression and physical disorders.
authors.affiliation: Department of Psychiatry & Depression Clinical Research Center, Chonnam National University Medical School, Kwangju, Korea.
authors.forename: Jae-Min
authors.initials: JM
authors.lastname: Kim
authors.forename: Robert
authors.initials: R
authors.lastname: Stewart
authors.forename: Sung-Wan
authors.initials: SW
authors.lastname: Kim
authors.forename: Su-Jin
authors.initials: SJ
authors.lastname: Yang
authors.forename: Il-Seon
authors.initials: IS
authors.lastname: Shin
authors.forename: Jin-Sang
authors.initials: JS
authors.lastname: Yoon
mesh_terms: D000368:Aged; D000375:Aging / Q000523:psychology; D015897:Comorbidity; D003866:Depressive Disorder / Q000453:epidemiology* / Q000523:psychology*; D005260:Female; D005500:Follow-Up Studies; D015577:Geriatric Assessment / Q000379:methods* / Q000706:statistics & numerical data; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D007723:Korea / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D009043:Motor Activity; D016017:Odds Ratio; D015995:Prevalence; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D012111:Residence Characteristics; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology* / Q000523:psychology*