HIGH SODIUM, LOW POTASSIUM INTAKE AND CHANGES OF BLOOD PRESSURE CATEGORY DURING 7.5 YEARS FOLLOW-UP PERIOD

Abstract

Objective: Our aim was to analyze association of sodium and potassium intake on clinical course i.e. changes of blood pressure (BP) category in general population during the 7.5 years of follow up. Design and method: Out of 1582 subjects (random rural sample) enrolled in ENAH study conducted in 2008–2010, 739 were invited for the second visit in 2015 and 377 subjects with reliable both urine samples (urine creatinine in normal ranges) were included in further analyses s (80m 297w; average age 52 ± 13.5). Blood pressure was measured three times (Omron M6) and mean values were calculated. Fasting blood and first morning (spot) urine samples were collected. Sodium and potassium were determined using Tanaka, Kawasaki and Intersalt equations. Potassium intake was further adjusted for intestinal intake (77%) and renal excretion (92%). Optimal, normal, high normal BP, untreated and treated hypertension (HT) were diagnosed in 20.9%, 15.3%, 12.9%, 19.1% and 31.5%, respectively. Results: Out of 377 subjects 185 (49%) worsened (WBP) and 47 (12.5%) improved BP (IBP) category. We failed to find differences between WBP and IBP in gender, BMI and eGFR. OBP and untreated HT worsened BP and treated HT improved BP more frequently than others. At basal there were no differences in sodium and potassium intake between WBP and IBP category. At the follow up visit sodium and potassium intake were higher in WBP than in IBP group (Tanaka 175.8 ± 39.3 vs 132.8 ± 33.6; p = 0.061, 38.6 ± 8.3 vs 35.6 ± 7.4; p = 0.027) with no differences in potassium intake and Na/K ratio. Salt intake >10 g/day was significantly more frequently found in WBP than in IBP (51% vs. 34.7%; X2 = 4.918; p = 0.047). Conclusions: Worsened BP category was associated with higher salt intake. Subjects with optimal BP and untreated hypertension most frequently worsened BP and changed BP category. Very low average potassium intake (<1.5 g/day in the whole group) is plausible explanation why beneficial effect of potassium intake on BP clinical course was not observed. To lower salt intake and to increase potassium intake should be recommended to general population and not only to hypertensives.