title: Risk factors for insomnia in a rural population.
abstract: OBJECTIVE
  This study compared in one data set the relative importance of most previously examined risk factors for different symptoms of insomnia.
  
  
  METHODS
  Data were obtained from personal interviews of 1,588 adults in a rural area. Statistical methods evaluated the association of 42 risk factors with any insomnia and each of four insomnia subtypes: difficulty with initiating sleep (DIS), difficulty maintaining sleep (DMS), early morning awakening (EMA), and restless sleep (RS).
  
  
  RESULTS
  Insomnia rates were greater in this rural population than most U.S. studies and greater in the United States than other countries. The correlations between insomnia subtype and energy level was highest for RS, -0.29, and lowest for EMA, -0.11. All sleep disturbances increased monotonically with depressive symptoms, but the increase was greatest for RS (r = 0.57) and weakest for EMA (r = 0.24). Anxiety and pain also were independently associated with each insomnia subtype. Insomnia problems of spouses were uncorrelated. Other risk factors were independently associated with some insomnia subtypes but not others. For example, the association of age with difficulty maintaining sleep was independent of health measures.
  
  
  CONCLUSIONS
  The results suggest that different insomnias have different rates and risk factors and therefore possibly different etiologies and management strategies.
authors.affiliation: Department of Family Medicine, The University of Iowa, Iowa City, IA, USA. arthur.hartz@hci.utah.edu
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Hartz
authors.forename: Jeanette M
authors.initials: JM
authors.lastname: Daly
authors.forename: Neal D
authors.initials: ND
authors.lastname: Kohatsu
authors.forename: Ann M
authors.initials: AM
authors.lastname: Stromquist
authors.forename: Gerald J
authors.initials: GJ
authors.lastname: Jogerst
authors.forename: Oladipo A
authors.initials: OA
authors.lastname: Kukoyi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003863:Depression / Q000453:epidemiology; D005260:Female; D006801:Humans; D007484:Iowa / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012044:Regression Analysis; D012307:Risk Factors; D012424:Rural Population; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology*