title: Low serum potassium levels and risk of type 2 diabetes: the Toranomon Hospital Health Management Center Study 1 (TOPICS 1).
abstract: OBJECTIVE
  Evidence has suggested that low serum potassium concentrations decrease insulin secretion, leading to glucose intolerance, and that hypokalaemia induced by diuretics increases the risk for diabetes in hypertensive individuals. However, no prospective study has investigated the association between serum potassium and the development of type 2 diabetes in a healthy cohort comprised of Asian individuals not being administered antihypertensive medications. This study aimed to investigate whether low serum potassium is associated with increased risk of type 2 diabetes in apparently healthy Japanese men.
  
  
  METHODS
  We followed 4,409 Japanese men with no history of diabetes, use of antihypertensives, renal dysfunction or liver dysfunction (mean ± SD age, 48.4 ± 8.4 years). Cox proportional hazards regression was used to estimate HRs for incident diabetes (fasting plasma glucose level ≥ 7.0 mmol/l, HbA(1c) ≥ 6.5% or self-reported) including serum potassium concentration as either a categorical or a continuous variable.
  
  
  RESULTS
  During a 5 year follow-up, 250 individuals developed type 2 diabetes. The lowest tertile of serum potassium (2.8-3.9 mmol/l) was independently associated with the development of diabetes after adjustment for known predictors (HR 1.57 [95% CI, 1.15-2.15]) compared with the highest tertile (4.2-5.4 mmol/l). Every 0.5 mmol/l lower increment in the baseline serum potassium level was associated with a 45% (12-87%) increased risk of diabetes.
  
  
  CONCLUSIONS
  Mild to moderately low serum potassium levels, within the normal range and without frank hypokalaemia, could be predictive of type 2 diabetes in apparently healthy Japanese men.
authors.affiliation: Department of Internal Medicine, University of Tsukuba Institute of Clinical Medicine, Ibaraki, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Heianza
authors.forename: S
authors.initials: S
authors.lastname: Hara
authors.forename: Y
authors.initials: Y
authors.lastname: Arase
authors.forename: K
authors.initials: K
authors.lastname: Saito
authors.forename: K
authors.initials: K
authors.lastname: Totsuka
authors.forename: H
authors.initials: H
authors.lastname: Tsuji
authors.forename: S
authors.initials: S
authors.lastname: Kodama
authors.forename: S D
authors.initials: SD
authors.lastname: Hsieh
authors.forename: N
authors.initials: N
authors.lastname: Yamada
authors.forename: K
authors.initials: K
authors.lastname: Kosaka
authors.forename: H
authors.initials: H
authors.lastname: Sone
mesh_terms: D000328:Adult; D044466:Asian People; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood*; D016016:Proportional Hazards Models; D012307:Risk Factors
chemical_list: D011188:Potassium