Several different formulae have been suggested to estimate
spot urinary sodium over 24-h. In this study the
INTERSALT formula provided the least bias information
regarding mean sodium intake when compared to the
Tanaka and Kawasaki formula. This finding is consistent
with the findings from Cogswell and colleagues who carried
out a validation study of predictive equations for 24-
h urinary sodium excretion in adults aged 18e64 years [9].