Sodium and potassium urinary excretion and their ratio in the elderly: results from the Nutrition UP 65 study

  • Pedro Moreira
  • Ana S. Sousa
  • Rita S. Guerra
  • Alejandro Santos
  • Nuno Borges
  • Cláudia Afonso
  • Teresa F. Amaral
  • Patrícia Padrão
Keywords: Sodium, potassium, sodium-to-potassium ratio, elderly, urinary excretion


Background: We aimed to describe urinary sodium and potassium excretion and their ratio in a representative
sample of Portuguese elderly population, according to sociodemographic characteristics and weight status.

Methods: A cluster sampling approach was used, representing older Portuguese adults (≥65 years) according
to age, sex, education level, and regional area within the Nutrition UP 65 study. This cross-sectional evaluation was conducted in 2015 and 2016. From a sample size of 1,500 participants, 1,318 were eligible for the present analysis, 57.3% were women, and 23.5% were aged ≥80 years. Sodium and potassium consumption was evaluated through one 24 h urinary excretion. Inadequate sodium intake was defined as ≥2,000 mg/day,
inadequate potassium intake was considered as <3,510 mg/day, and inadequate sodium-to-potassium ratio
was defined as >1, according to the World Health Organization cutoffs.

Results: The proportion of the participants with an inadequate intake was 80.0% in women and 91.5% in
men (sodium), 96.2% of women and 79.4% of men (potassium), and 98.4% of women and 99.1% of men (sodium-to-potassium ratio). Higher sodium adequacy was observed among the older elderly, unmarried, with
lower household income, and underweight/normal weight. Higher potassium adequacy was observed in the
younger elderly, married, and with higher income.

Conclusion: The majority of the Portuguese elderly population was classified as having inadequate sodium,
potassium, and sodium-to-potassium ratio urinary excretion. Therefore, strategies for reducing
sodium and increasing potassium intake are priorities in the Portuguese elderly population.


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How to Cite
Moreira P., Sousa A. S., Guerra R. S., Santos A., Borges N., Afonso C., Amaral T. F., & Padrão P. (2018). Sodium and potassium urinary excretion and their ratio in the elderly: results from the Nutrition UP 65 study. Food & Nutrition Research, 62.
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