title: Sleep apnea and the risk of dementia: a population-based 5-year follow-up study in Taiwan.
abstract: BACKGROUND
  Sleep apnea (SA) has been associated with cognitive impairment. However, no data regarding the risk of dementia in patients with SA has been reported in the general population. This retrospective matched-control cohort study was designed to estimate and compare the risk of dementia in SA and non-SA patients among persons aged 40 and above over a 5-year period follow-up.
  
  
  METHODS
  We conducted a nationwide 5-year population-based study using data retrieved from the Longitudinal Health Insurance Database 2005 (LHID2005) in Taiwan. The study cohort comprised 1414 patients with SA aged 40 years who had at least 1 inpatient service claim or 1 ambulatory care claim. The comparison cohort comprised 7070 randomly selected patients who were matched with the study group according to sex, age, and index year. We performed Cox proportional-hazards regressions to compute the 5-year dementia-free survival rates after adjusting for potentially confounding factors.
  
  
  RESULTS
  The SA patients in this study had a 1.70-times greater risk of developing dementia within 5 years of diagnosis compared to non-SA age- and sex-matched patients, after adjusting for other risk factors (95% confidence interval (CI) = 1.26-2.31; P < .01). For the gender-dependent effect, only females with SA were more likely to develop dementia (adjust HR: 2.38, 95% CI =1.51-3.74; P < .001). For the age-dependent effect of different genders, males with SA aged 50-59 years had a 6.08 times greater risk for developing dementia (95% CI = 1.96-18.90), and females with SA aged ≥ 70 years had a 3.20 times greater risk of developing dementia (95% CI =1.71-6.00). For the time-dependent effect, dementia may be most likely to occur in the first 2.5 years of follow-up (adjusted HR:2.04, 95% CI =1.35-3.07).
  
  
  CONCLUSIONS
  SA may be a gender-dependent, age-dependent, and time-dependent risk factor for dementia.
authors.affiliation: Department of Healthcare Management, Yuanpei University, HsinChu, Taiwan.
authors.forename: Wei-Pin
authors.initials: WP
authors.lastname: Chang
authors.forename: Mu-En
authors.initials: ME
authors.lastname: Liu
authors.forename: Wei-Chiao
authors.initials: WC
authors.lastname: Chang
authors.forename: Albert C
authors.initials: AC
authors.lastname: Yang
authors.forename: Yan-Chiou
authors.initials: YC
authors.lastname: Ku
authors.forename: Jei-Tsung
authors.initials: JT
authors.lastname: Pai
authors.forename: Hsiao-Ling
authors.initials: HL
authors.lastname: Huang
authors.forename: Shih-Jen
authors.initials: SJ
authors.lastname: Tsai
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D003704:Dementia / Q000150:complications* / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012307:Risk Factors; D012727:Sex Characteristics; D012737:Sex Factors; D012891:Sleep Apnea Syndromes / Q000150:complications*; D013624:Taiwan / Q000453:epidemiology; D013997:Time Factors