Swiss Medical Weekly (Feb 2017)

Associations of sodium, potassium and protein intake with blood pressure and hypertension in Switzerland

  • Nicolas Glatz,
  • Aline Chappuis,
  • David Conen,
  • Paul Erne,
  • Antoinette Péchère-Bertschi,
  • Idris Guessous,
  • Valentina Forni,
  • Luca Gabutti,
  • Franco Muggli,
  • Augusto Gallino,
  • Daniel Hayoz,
  • Isabelle Binet,
  • Paolo Suter,
  • Fred Paccaud,
  • Murielle Bochud,
  • Michel Burnier,
  • Swiss Medical Weekly

DOI
https://doi.org/10.4414/smw.2017.14411
Journal volume & issue
Vol. 147, no. 0708

Abstract

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BACKGROUND Nutritional factors play an important role in the regulation of blood pressure and in the development of hypertension. In this analysis, we explored the associations of 24-hour urinary Na+, K+ and urea excretion with blood pressure levels and the risk of hypertension in the Swiss population, taking regional linguistic differences into account. METHODS The Swiss Survey on Salt is a population based cross-sectional study that included 1336 subjects from the three main linguistic regions (French, German and Italian) of Switzerland. Blood pressure was measured with a validated oscillometric Omron HEM 907 device. Hypertension was defined as current antihypertensive treatment or a mean systolic blood pressure >140 mm Hg and/or diastolic >90 mm Hg, based on eight blood pressure measurements performed at two visits. Na+, K+ and urea excretion were assessed in 24-hour urine collections. We use multiple logistic/linear regressions to explore the associations of urine Na+, K+ and urea with blood pressure / hypertension, taking into account potential confounders and effect modifiers. RESULTS The prevalence of hypertension was 30%, 26% and 17% in the German-, French- and Italian- speaking regions respectively, (p-value across regions <0.001). In the Swiss adult population, besides age, sex, and body mass index, urinary Na+ excretion was positively associated with systolic blood pressure and hypertension. Urinary K+ excretion tended to be negatively associated with blood pressure but this was not significant (p = 0.08). Hypertensive people had a higher 24-hour urinary Na+/K+ ratio than normotensive people (p = 0.003). Urinary urea excretion was associated with neither blood pressure nor hypertension. Participants from the German-speaking region had a higher likelihood of having a high systolic blood pressure. CONCLUSIONS We confirm a high prevalence of elevated blood pressure in Swiss adults, including regional differences. In Switzerland, urinary Na+ excretion is associated positively with blood pressure and hypertension, independently of urinary K+ and urea excretion. The observed differences in blood pressure levels across linguistic regions are independent of the urinary Na+, K+ and urea excretion.

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