Hypertension and sodium transport in 390 healthy adults in Chicago

A total of 390 people undergoing routine examinations at the Portes Center, a screening center in Chicago, and at the Northwestern Memorial Hospital employee health service, underwent an in-depth battery of tests designed to explore the relationships of both intracellular erythrocyte sodium and sodium-lithium countertransport with age, race, gender, body mass index, pattern of alcohol intake, exogenous hormone use and the presence of hypertension. Erythrocyte sodium was significantly higher in blacks than in whites and in men than in women aged 20-39 years. Relationships of erythrocyte sodium with race and gender, as well as inverse associations with alcohol intake in men, and positive associations with age and the presence of hypertension in women were significant on multivariate analysis after control for other variables. Sodium-lithium countertransport was significantly higher in whites than in blacks and in men than in women aged 20-59 years. Associations of sodium-lithium countertransport with race and gender as well as positive associations of sodium-lithium countertransport with body mass index in men and women were significant on multivariate analysis after control for other variables. Age-related gender differences in both sodium-lithium countertransport and erythrocyte sodium, as well as the association of erythrocyte sodium with the presence of hypertension in women but not in men, suggest a hormonal interaction with sodium transport in the development of hypertension.