Relationships between red cell cation contents and blood pressure level.

Abstract

Red cell sodium (R-Na), potassium (R-K) and sodium to potassium ratio (R-Na/K) were studied in 2,542 adults participating in periodic medical examinations. The mean values of R-Na and R-Na/K in untreated borderline (n = 406) and definite hypertensives (n = 485) were higher than those in normotensives (n = 1,651), but that of R-K was not different among the groups. The increased R-Na and R-Na/K in the hypertensives were observed only in those under 50 years, but not in those 50 years and over. In the normotensive subjects, age and sex affected the intraerythrocyte cation contents, but a positive family history of hypertension did not. Although a few characteristics correlated with both R-Na and mean blood pressure, and with both R-Na/K and mean blood pressure, multiple regression analyses revealed that R-Na and R-Na/K independently and significantly contributed to the variation in mean blood pressure. It was also indicated that these relations of R-Na and R-Na/K to mean blood pressure were significant in those under 50 years, but not in those 50 years and over. While several characteristics confound the relationships between red cell cation contents and blood pressure, these results suggest that the contributions of R-Na and R-Na/K to the mechanisms of human hypertension still persist in young to middle-aged people.