title: Age-related cataract, cataract surgery and subsequent mortality: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Changes in lens may reflect the status of systemic health of human beings but the supporting evidences are not well summarized yet. We aimed to determine the relationship of age-related cataract, cataract surgery and long-term mortality by pooling the results of published population-based studies.
  
  
  METHODS
  We searched PubMed and Embase from their inception till March, 2014 for population-based studies reporting the associations of any subtypes of age-related cataract, cataract surgery with all-cause mortality. We pooled the effect estimates (hazards ratios [HRs]) under a random effects model.
  
  
  RESULTS
  Totally, we identified 10 unique population-based studies including 39,659 individuals at baseline reporting the associations of any subtypes of cataract with all-cause mortality from 6 countries. The presence of any cataract including cataract surgery was significantly associated with a higher risk of death (pooled HR: 1.43, 95% CI, 1.21, 2.02; P<0.001; I(2) = 64.2%). In the meta-analysis of 9 study findings, adults with nuclear cataract were at higher risks of mortality (pooled HR: 1.55, 95% CI, 1.17, 2.05; P = 0.002; I(2) = 89.2%). In the meta-analysis of 8 study findings, cortical cataract was associated with higher risks of mortality (pooled HR: 1.26, 95% CI, 1.12, 1.42; P<0.001, I(2) = 29.7%). In the meta-analysis of 6 study findings, PSC cataract was associated with higher risks of mortality (pooled HR: 1.37, 95% CI, 1.04, 1.80; P = 0.03; I(2) = 67.3%). The association between cataract surgery and mortality was marginally non-significant by pooling 8 study findings (pooled HR: 1.27, 95% CI, 0.97, 1.66; P = 0.08; I(2)= 76.6%).
  
  
  CONCLUSIONS
  All subtypes of age-related cataract were associated with an increased mortality with nuclear cataract having the strongest association among the 3 cataract subtypes. However, cataract surgery was not significantly related to mortality. These findings indicated that changes in lens may serve as markers for ageing and systemic health in general population.
authors.affiliation: Lixiang Eye Hospital of Soochow University, Suzhou, China.
authors.forename: E
authors.initials: E
authors.lastname: Song
authors.affiliation: School of Public Health, Medical College of Soochow University, Suzhou, China.
authors.forename: Hongpeng
authors.initials: H
authors.lastname: Sun
authors.affiliation: School of Public Health, Medical College of Soochow University, Suzhou, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Xu
authors.affiliation: School of Public Health, Medical College of Soochow University, Suzhou, China.
authors.forename: Yana
authors.initials: Y
authors.lastname: Ma
authors.affiliation: School of Public Health, Medical College of Soochow University, Suzhou, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhu
authors.affiliation: School of Public Health, Medical College of Soochow University, Suzhou, China.
authors.forename: Chen-Wei
authors.initials: CW
authors.lastname: Pan
mesh_terms: D000375:Aging; D002386:Cataract / Q000401:mortality*; D002387:Cataract Extraction; D006801:Humans; D016016:Proportional Hazards Models; D016896:Treatment Outcome