Mortality, and cardiovascular events with respect to urinary sodium and potassium excretion

The optimal range of sodium intake with respect to cardiovascular health remains controversial.     The Canadian and multinational scientists from 17 countries obtained morning fasting urine samples from 101,945 people (24-hour sodium and potassium excretion). They examined the association between urinary Na+ and K+ excretion and the relationship with respect to outcome (death) and major cardiovascular events.     Estimated average sodium and potassium excretion was 4.93 gr and 2.12 gr per day, respectively. With a mean follow-up of 3.7 years, the composite outcome occurred in 3,317 participants. As compared with an estimated sodium excretion of 4 - 6 gr per day, a higher estimated sodium excretion (>/= 7 gr per day) was associated with an increased risk of the composite outcome, as well as increased risks of death and major cardiovascular events considered separately. The association between a high estimated sodium excretion and the composite outcome was strongest among participants with hypertension, with an increased risk at an estimated sodium excretion of 6 gr or more per day. As compared with the reference range, an estimated sodium excretion that was below 3 gr per day was also associated with an increased risk of the composite outcome. As compared with an estimated potassium excretion that was less than 1.50 gr per day, higher potassium excretion was associated with a reduced risk of the composite outcome.     In this study in which sodium intake was estimated on the basis of measured urinary excretion, an estimated sodium intake between 3 gr per day and 6 gr per day was associated with a lower risk of death and cardiovascular events than was either a higher or lower estimated level of intake. As compared with an estimated potassium excretion that was less than 1.50 gr per day, higher potassium excretion was associated with a lower risk of death and cardiovascular events.