title: The relationship between sodium concentrations in spot urine and blood pressure increases: a prospective study of Japanese general population: the Circulatory Risk in Communities Study (CIRCS).
abstract: BACKGROUND
  Although several cross-sectional and intervention studies showed that sodium intake or excretion was associated with blood pressure levels, no prospective study has examined the long-term association between sodium excretion in spot urine and blood pressure changes.
  
  
  METHODS
  We conducted a prospective study of 889 normotensive subjects (295 men and 594 women, mean age 57.3 years) who underwent the baseline survey including spot urine test in 2005 and the follow-up survey in 2009 to 2011 (mean follow-up period: 5.8 years). We examined the association between sodium concentration in spot urine, a validated index of sodium excretion occurring over 24-h, and blood pressure changes between baseline and follow-up survey in all, non-overweight (body mass index(BMI) ≤ 25 kg/m(2)) and overweight normotensives.
  
  
  RESULTS
  For all subjects, sodium concentrations in spot urine were not associated with either systolic or diastolic blood pressure changes. When stratified by BMI at baseline survey, sodium concentrations were positively associated with systolic blood pressure changes in non-overweight subjects, but not in overweight subjects. After adjustment for age, sex, BMI, alcohol intake status, current smoking and estimated glomerular filtration rate, the multivariable-adjusted mean values of the systolic blood pressure change among non-overweight subjects was +7.3 mmHg in the highest quartiles of sodium concentrations, while it was +3.9 mmHg in the lowest quartile (P for difference = 0.021, P for trend = 0.040). After further adjustment of baseline blood pressure levels, the association was slightly weakened; the multivariable-adjusted mean values of the systolic blood pressure changes were +7.0 mmHg and +4.2 mmHg (P for difference = 0.047, P for trend = 0.071).
  
  
  CONCLUSIONS
  High sodium concentrations in spot urine were associated with subsequent systolic blood pressure increases among non-overweight normotensive individuals. (272 words).
authors.affiliation: Department of Public Health, Dokkyo Medical University, School of Medicine, 880 Kita-kobayashi, Mibu, Shimotsuga-gun, Tochigi, 321-0293, Japan. starlight-shower@nifty.com.|Department of Public Health Medicine, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan. starlight-shower@nifty.com.
authors.forename: Mitsumasa
authors.initials: M
authors.lastname: Umesawa
authors.affiliation: Department of Public Health Medicine, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan. yamagishi.kazumas.ge@u.tsukuba.ac.jp.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Yamagishi
authors.affiliation: Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, 565-0871, Japan. hiroyuki_noda@env.go.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Noda
authors.affiliation: Department of Public Health, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. a-noda@juntendo.ac.jp.
authors.forename: Ai
authors.initials: A
authors.lastname: Ikeda
authors.affiliation: Department of Public Health Medicine, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan. shinobu.sawachi@biogen.com.|Biogen Japan Ltd., 14th floor 1-4-1 Nihonbashi, Chuo-ku, Tokyo, 103-0027, Japan. shinobu.sawachi@biogen.com.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Sawachi
authors.affiliation: Osaka Center for Cancer and Cardiovascular Diseases Prevention, 1-3-2 Nakamichi, Higashinari-ku, Osaka, 537-0025, Japan. isao-muraki@umin.ac.jp.
authors.forename: Isao
authors.initials: I
authors.lastname: Muraki
authors.affiliation: Department of Public Health Medicine, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan. clchei@hotmail.com.
authors.forename: Choy-Lye
authors.initials: CL
authors.lastname: Chei
authors.affiliation: Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, 565-0871, Japan. cuirenzhe@hotmail.com.
authors.forename: Renzhe
authors.initials: R
authors.lastname: Cui
authors.affiliation: Department of Public Health, Dokkyo Medical University, School of Medicine, 880 Kita-kobayashi, Mibu, Shimotsuga-gun, Tochigi, 321-0293, Japan. nagao@dokkyomed.ac.jp.
authors.forename: Masanori
authors.initials: M
authors.lastname: Nagao
authors.affiliation: Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, 565-0871, Japan. fwge1119@mb.infoweb.ne.jp.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ohira
authors.affiliation: Department of Community Health, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan. sankai_tomoko@md.tsukuba.ac.jp.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Sankai
authors.affiliation: Department of Public Health, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. tt9178tt9178@gmail.com.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tanigawa
authors.affiliation: Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, 565-0871, Japan. kitamura@pbhel.med.osaka-u.ac.jp.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kitamura
authors.affiliation: Osaka Center for Cancer and Cardiovascular Diseases Prevention, 1-3-2 Nakamichi, Higashinari-ku, Osaka, 537-0025, Japan. kiyama@osaka-ganjun.jp.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kiyama
authors.affiliation: Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, 565-0871, Japan. iso@pbhel.med.osaka-u.ac.jp.
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Iso
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000652:urine; D001794:Blood Pressure; D015897:Comorbidity; D005260:Female; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology* / Q000652:urine*; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009318:Natriuresis; D009765:Obesity / Q000453:epidemiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D012964:Sodium / Q000652:urine*; D017673:Sodium Chloride, Dietary / Q000009:adverse effects*; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; D017673:Sodium Chloride, Dietary; D012964:Sodium