Higher levels of sodium intake are reported to be associated with higher blood pressure. Whether this relationship varies according to levels of sodium or potassium intake and in different populations is unknown. The researchers studied 102,216 adults from 18 countries. Estimates of 24-hour sodium and potassium excretion were made from a single fasting morning urine specimen and were used as surrogates for intake. They assessed the relationship between electrolyte excretion and blood pressure, as measured with an automated device.