title: Association between Benzodiazepine Use and Dementia: A Meta-Analysis.
abstract: BACKGROUND
  The association between long-term benzodiazepine use and risk of dementia remains controversial. Therefore, current study aimed to quantify this association, and to explore a potential dose-response pattern.
  
  
  METHODS
  We searched PubMed, Embase and the Cochrane Library through August 17, 2014. We included nested case-control or prospective cohort studies that provided risk estimates on the association of benzodiazepine use with risk of dementia, and a clear definition of status of benzodiazepine use. Overall effect size was calculated using a random-effects model.
  
  
  RESULTS
  Six studies were eligible for inclusion, involving 11,891 dementia cases and 45,391 participants. Compared with never users, pooled adjusted risk ratios (RRs) for dementia were 1.49 (95% confidence interval (CI) 1.30-1.72) for ever users, 1.55 (95% CI 1.31-1.83) for recent users, and 1.55 (95% CI 1.17-2.03) for past users. The risk of dementia increased by 22% for every additional 20 defined daily dose per year (RR, 1.22, 95%CI 1.18-1.25). When we restricted our meta-analyses to unadjusted RRs, all initial significant associations persisted.
  
  
  CONCLUSIONS
  Long-term benzodiazepine users have an increased risk of dementia compared with never users. However, findings from our study should be treated with caution due to limited studies and potential reverse causation. Large prospective cohort studies with long follow-up duration are warranted to confirm these findings.
authors.affiliation: The Second Student Office of Chongqing Medical University, Chongqing, China.
authors.forename: GuoChao
authors.initials: G
authors.lastname: Zhong
authors.affiliation: The Second Student Office of Chongqing Medical University, Chongqing, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Public Health and Management, Chongqing Medical University, Chongqing, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Public Health and Management, Chongqing Medical University, Chongqing, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001569:Benzodiazepines / Q000008:administration & dosage* / Q000009:adverse effects*; D016022:Case-Control Studies; D003704:Dementia / Q000139:chemically induced* / Q000209:etiology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D016017:Odds Ratio; D011446:Prospective Studies; D012306:Risk; D013997:Time Factors
chemical_list: D001569:Benzodiazepines