title: Association Between Small Decrease in Serum Sodium Concentration within the Normal Range and All-Cause and Cardiovascular Mortality in Elderly Adults over 5 Years.
abstract: OBJECTIVE
  To determine the importance of a decrease in serum sodium concentration within the normal range in elderly adults.
  
  
  METHODS
  Prospective cohort.
  
  
  METHODS
  The Korean Longitudinal Study on Health and Aging.
  
  
  METHODS
  Randomly selected, community-based elderly population with a corrected serum sodium level between 135.0 and 145.0 mEq/L (N = 949).
  
  
  METHODS
  Survival status was determined during 63.3 ± 16.6 months of follow-up.
  
  
  RESULTS
  Participants were divided into corrected sodium groups as follows: 73 (7.7%) in Group 1 (sodium 135.0-138.0 mEq/L), 635 (66.9%) in Group 2 (sodium 138.1-142.0 mEq/L), and 241 (25.4%) in Group 3 (sodium 142.1.0-145.0 mEq/L). There were 34 (46.6%) deaths in Group 1, 124 (19.5%) in Group 2, and 52 (21.6%) in Group 3 (P < .001). In a Cox proportional hazards analysis, a 2-mEq/L higher sodium level reduced the risk of death by 14.9% (95% confidence interval (CI) = 0.1-27.4%, P = .048). Group 1 had risk of mortality that was 2.7 times as high as that of Group 2 (95% CI = 1.76-4.11, P < .001). Participants with a measured sodium level of 138.0 mEq/L or less and a corrected sodium level greater than 138.0 mEq/L had a better survival rate than those with a measured sodium level of 138.0 mEq/L or less and a corrected sodium level of 138.0 mEq/L or less.
  
  
  CONCLUSIONS
  A slightly lower serum sodium concentration within the normal range was a major risk factor for mortality in elderly adults. Sodium level corrected according to serum glucose concentration was a more meaningful risk factor than measured sodium level.
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seong-Nam, Korea.|Department of Immunology, Postgraduate School, Seoul National University, Seoul, Korea.
authors.forename: Shin Y
authors.identifier: http://orcid.org/0000-0002-6844-0614
authors.initials: SY
authors.lastname: Ahn
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seong-Nam, Korea.
authors.forename: Yoon S
authors.initials: YS
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seong-Nam, Korea.
authors.forename: Seong W
authors.initials: SW
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seong-Nam, Korea.
authors.forename: Seon H
authors.initials: SH
authors.lastname: Baek
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seong-Nam, Korea.
authors.forename: Sejoong
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seong-Nam, Korea.|Department of Internal Medicine, Seoul National University, Seoul, Korea.
authors.forename: Ki Y
authors.initials: KY
authors.lastname: Na
authors.affiliation: Department of Psychiatry, Seoul National University, Seoul, Korea.
authors.forename: Ki W
authors.initials: KW
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seong-Nam, Korea.|Department of Internal Medicine, Seoul National University, Seoul, Korea.
authors.forename: Dong-Wan
authors.initials: DW
authors.lastname: Chae
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seong-Nam, Korea.|Department of Immunology, Postgraduate School, Seoul National University, Seoul, Korea.|Department of Internal Medicine, Seoul National University, Seoul, Korea.|Renal Institute, Clinical Research Center, College of Medicine, Seoul National University, Seoul, Korea.
authors.forename: Ho J
authors.initials: HJ
authors.lastname: Chin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000032:analysis; D002318:Cardiovascular Diseases / Q000097:blood / Q000401:mortality*; D002423:Cause of Death; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000097:blood / Q000401:mortality*; D008137:Longitudinal Studies; D008297:Male; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012016:Reference Values; D056910:Republic of Korea; D012307:Risk Factors; D012964:Sodium / Q000097:blood*; D015996:Survival Rate
chemical_list: D001786:Blood Glucose; D012964:Sodium
keywords: elderly population; mortality; sodium