Estimation of salt intake by questionnaire.

A questionnaire designed to assess salt intake was tested. This involved principal components analysis of responses from 155 subjects to find the underlying components related to the questions. Validation of the questionnaire used 7-day urinary sodium excretion for 33 subjects, along with table and cooking salt usage over 7-days. This gave comparatively good prediction for total intake (r = 0.66) and table salt use (r = 0.70) but not for cooking salt use (r = 0.17). Test-retest reliability for the estimate of total intake was r = 0.75. This method would therefore offer a useful estimate of total intake, especially where group means are required rather than accurate estimates of individual intakes.