title: Dietary sodium-to-potassium ratio as a risk factor for stroke, cardiovascular disease and all-cause mortality in Japan: the NIPPON DATA80 cohort study.
abstract: To evaluate the impact of dietary sodium and potassium (Na-K) ratio on mortality from total and subtypes of stroke, cardiovascular disease (CVD) and all causes, using 24-year follow-up data of a representative sample of the Japanese population.
  
  
  
  Prospective cohort study.
  
  
  
  In the 1980 National Cardiovascular Survey, participants were followed for 24 years (NIPPON DATA80, National Integrated Project for Prospective Observation of Non-communicable Disease And its Trends in the Aged). Men and women aged 30-79 years without hypertensive treatment, history of stroke or acute myocardial infarction (n=8283) were divided into quintiles according to dietary Na-K ratio assessed by a 3-day weighing dietary record at baseline. Age-adjusted and multivariable-adjusted HRs were calculated using the Mantel-Haenszel method and Cox proportional hazards model.
  
  
  
  Mortality from total and subtypes of stroke, CVD and all causes.
  
  
  
  A total of 1938 deaths from all causes were observed over 176 926 person-years. Na-K ratio was significantly and non-linearly related to mortality from all stroke (p=0.002), CVD (p=0.005) and total mortality (p=0.001). For stroke subtypes, mortality from haemorrhagic stroke was positively related to Na-K ratio (p=0.024). Similar relationships were observed for men and women. The observed relationships remained significant after adjustment for other risk factors. Quadratic non-linear multivariable-adjusted HRs (95% CI) in the highest quintile versus the lowest quintile of Na-K ratio were 1.42 (1.07 to 1.90) for ischaemic stroke, 1.57 (1.05 to 2.34) for haemorrhagic stroke, 1.43 (1.17 to 1.76) for all stroke, 1.39 (1.20 to 1.61) for CVD and 1.16 (1.06 to 1.27) for all-cause mortality.
  
  
  
  Dietary Na-K ratio assessed by a 3-day weighing dietary record was a significant risk factor for mortality from haemorrhagic stroke, all stroke, CVD and all causes among a Japanese population.
authors.affiliation: Research Institute of Strategy for Prevention, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Okayama
authors.affiliation: Department of Health and Nutrition, University of Human Arts and Sciences, Saitama, Japan.
authors.forename: Nagako
authors.initials: N
authors.lastname: Okuda
authors.affiliation: Department of Public Health, Shiga University of Medical Science, Shiga, Otsu, Japan Center for Epidemiologic Research in Asia, Shiga University of Medical Science, Shiga, Otsu, Japan.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Miura
authors.affiliation: Department of Preventive Medicine and Public Health, Keio University, Tokyo, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Okamura
authors.affiliation: Department of Hygiene and Preventive Medicine, Fukushima Medical University, Fukushima, Japan.
authors.forename: Takehito
authors.initials: T
authors.lastname: Hayakawa
authors.affiliation: Second Department of Internal Medicine, Sapporo Medical University, Sapporo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Akasaka
authors.affiliation: Second Department of Internal Medicine, Sapporo Medical University, Sapporo, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Ohnishi
authors.affiliation: Division of Medical and Behavioral Subjects, Sapporo Medical University School of Health Science, Sapporo, Japan.
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Saitoh
authors.affiliation: Department of Nutrition and Health, Chiba Prefectural University of Health Sciences, Chiba, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Arai
authors.affiliation: Department of Environmental Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kiyohara
authors.affiliation: Department of Public Health, Shiga University of Medical Science, Shiga, Otsu, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Takashima
authors.affiliation: Department of Food and Nutrition, Osaka City University, Osaka, Japan.
authors.forename: Katsushi
authors.initials: K
authors.lastname: Yoshita
authors.affiliation: Department of Public Health, Shiga University of Medical Science, Shiga, Otsu, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Fujiyoshi
authors.affiliation: Center for Epidemiologic Research in Asia, Shiga University of Medical Science, Shiga, Otsu, Japan.
authors.forename: Maryam
authors.initials: M
authors.lastname: Zaid
authors.affiliation: Department of Hygiene and Public Health, Teikyo University, Tokyo, Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ohkubo
authors.affiliation: Department of Public Health, Shiga University of Medical Science, Shiga, Otsu, Japan Center for Epidemiologic Research in Asia, Shiga University of Medical Science, Shiga, Otsu, Japan.
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Ueshima
mesh_terms: D000328:Adult; D000368:Aged; D002545:Brain Ischemia; D002318:Cardiovascular Diseases / Q000401:mortality; D002423:Cause of Death; D004032:Diet; D015930:Diet Records; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D020300:Intracranial Hemorrhages / Q000401:mortality; D007564:Japan; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000008:administration & dosage*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012982:Sodium, Dietary / Q000008:administration & dosage*; D020521:Stroke / Q000401:mortality*
chemical_list: D012982:Sodium, Dietary; D011188:Potassium
keywords: NUTRITION & DIETETICS; cardiovascular disease; potassium; prospective cohort; sodium