The prevalence of salt sensitivity in an African-American adolescent population

This study examined the prevalence of salt-sensitivity (SS) in 140 healthy African-American adolescents. SS was defined as an increase in mean blood pressure > or =5 mm Hg from a 5-day low salt (Na+) diet (50 mmol/24 hr) to a 10-day high Na+ diet (150 mmol/24 hr NaCl supplement); remaining subjects were classified as salt-resistant (SR). Dietary compliance was defined as Na+ excretion < or =50 mmol/24 hr for the low Na+ diet and > or =165 mmol/24 hr for the high NaCl supplement diet. 31 (22%) subjects were classified as SS and 109 (78%) as SR. There were no significant differences between SS and SR subjects on baseline characteristics, family history of hypertension, or on resting blood pressure or heart rate measures. As expected, SS subjects showed a greater increase in mean, systolic, and diastolic blood pressures (P<.001 for all) than SR subjects in response to the high NaCl supplement. There was a greater increase in weight (P<.01) and Quetelet Index (P<.05) for SS than SR subjects in response to Na+ loading. These results are the first to show that SS is prevalent in a subgroup of healthy African-American adolescents.