VARIABILITY IN SALT SENSITIVITY CLASSIFICATIONS IN BLACK-MALE VERSUS FEMALE ADOLESCENTS

Salt sensitivity (changes in blood pressure in response to alterations in salt intake) may be a risk factor for hypertension:In the present study, we examined the prevalence of salt sensitivity based on two dif ferent classifications in healthy black male and female adolescents (a ged 13 to 16 years). A total of 135 black adolescents participated in a 50 mmol/24 h low sodium diet for 5 days and a 150 mmol/24 h NaCl sup plement for 10 days. Dietary compliance was defined as sodium excretio n less than or equal to 50 mmol/24 h for the low sodium diet and great er than or equal to 165 mmol/24 h for the high NaCl supplement. Salt s ensitivity was defined by two classifications: (1) as a decrease in me an blood pressure greater than or equal to 5 mm Hg from baseline to th e low sodium diet, and (2) as an increase in mean blood pressure great er than or equal to 5 mm Hg from the low sodium diet to the high NaCl supplement. With classification 1, 14% of boys were identified as salt sensitive compared with 22% of girls. With classification 2, however, 31% of boys were identified as salt sensitive compared with 18% of gi rls. Analyses based on changes in systolic pressure demonstrated simil ar findings across sex, although overall classifications based on syst olic pressure yielded a greater percentage of salt-sensitive subjects. These sex differences in classification patterns were not due to diff erences in other important variables, such as changes in sodium excret ion, potassium excretion, or Quetelet index. These results suggest tha t the prevalence of salt sensitivity differs by sex depending on the t ype of protocol used for the classification of salt sensitivity in a b lack pediatric population.