title: The association of angiotensin-converting enzyme gene insertion/deletion polymorphisms with adaptation to high altitude: A meta-analysis.
abstract: BACKGROUND
  Fluid retention is linked to the physiology and pathophysiology of humans at high altitude (HA). The angiotensin-converting enzyme (ACE) gene plays a role in the regulation of plasma volume and vascular tone.
  
  
  METHODS
  In this meta-analysis, eligible studies published before 1 September 2015 that focused on the association between the ACE insertion/deletion (I/D) polymorphism and HA adaption were identified by searching the PubMed, Web of Science, Embase and Medline online databases. We used a fixed-effects model and assessed the study qualities multiple times.
  
  
  RESULTS
  The seven selected studies included a total of 582 HA-native individuals and 497 low-altitude controls, and these subjects were analyzed for the ACE I/D gene polymorphism. A significant association was found between the ACE DD genotype and HA maladaptation. The results for genotype DD versus ID + II were as follows: Odds ratio (OR) = 0.46; 95% CI 0.31-0.70; p = 0.0002. The results for genotype ID versus DD were as follows: OR = 1.97; 95% CI 1.27-3.06; p = 0.002.
  
  
  CONCLUSIONS
  Our findings suggested that the DD genotype of ACE is a risk factor for HA maladaptation and that the presence of fewer ACE DD allele carriers in a population indicates a greater ability of that population to adapt to HA.
authors.affiliation: Department of Military Medical Geography, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China Battalion 5 Cadet Brigade, Third Military Medical University, Chongqing, China Key Laboratory of High-altitude Medicine, Ministry of Education, Third Military Medical University, Chongqing, China.
authors.forename: Yuxiao
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Military Medical Geography, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China Battalion 5 Cadet Brigade, Third Military Medical University, Chongqing, China Key Laboratory of High-altitude Medicine, Ministry of Education, Third Military Medical University, Chongqing, China.
authors.forename: Hongxiang
authors.initials: H
authors.lastname: Lu
authors.affiliation: Key Laboratory of High-altitude Medicine, Ministry of Education, Third Military Medical University, Chongqing, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Military Medical Geography, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China Key Laboratory of High-altitude Medicine, Ministry of Education, Third Military Medical University, Chongqing, China luoyongjun2011@gmail.com.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Luo
mesh_terms: D000531:Altitude; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D054643:INDEL Mutation / Q000235:genetics*; D016254:Mutagenesis, Insertional / Q000235:genetics*; D007703:Peptidyl-Dipeptidase A / Q000235:genetics*
chemical_list: C488034:ACE protein, human; D007703:Peptidyl-Dipeptidase A
keywords: Adaptation; altitude; altitude disorders; altitude sickness; angiotensin-converting enzyme; deletion; genotype; high-altitude; hypoxia; insertion; meta-analysis; oxygen absorption; polymorphism