Sex and ethnic differences associated with urinary sodium and potassium in African-American US white and Nigerian college students.

BP and urinary sodium and potassium were assessed in 183 African-American, 113 US white and 72 Nigerian college students. SBP was higher in African-American males compared with Nigerian and US white males (123.1, 117.6 and 115.7 mmHg, respectively, P < 0.05). There were no significant differences observed between African-American and white male students in overnight urinary excretion rates of sodium and potassium. In contrast, African-American females excreted more sodium (41.0 vs. 31.3 mEq per 8 hours, P < 0.01) and potassium (12.0 vs. 8.9 mEq per 8 hours, P < 0.05) compared with white females. Only among the white students was a significant sex difference observed in urinary electrolyte excretion rates, where males excreted at higher rates than females. Multiple regression models for the African-Americans revealed that potassium explained only 4% of the SBP variance. Among the US whites and Nigerians, sodium explained 4.9% and 6.8%, respectively, of the DBP variance.