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