Salt preference according to a questionnaire vs. dietary salt intake estimated by a spot urine method in participants at a health check-up center.

OBJECTIVE: Salt intake restriction is important to health maintenance in subjects tending toward excessive intake. For convenience salt intake is ordinarily estimated at health check up centers using a salt-preference questionnaire, but whether or not the questionnaire identifies excessive salt consumers is unclear.
METHODS: Daily salt intake in 725 subjects including 452 men examined at our health-check center was estimated by a spot urine method developed by Kawasaki et al (Clin Exp Pharmacol Physiol 20:7-14, 1993). Results from the questionnaire were used to divide into salt preference and non-salt preference groups.
RESULTS: Daily salt intake estimated by the spot urine method was 13.5+/-3.5 g in male subjects and 12.4+/-3.1 g in female subjects. Salt preference subjects included 42% men and 24% of women. As a daily salt intake of less than 10 g is recommended for the general population in Japan, subjects whose salt intake exceeded 10 g were considered excessive salt consumers. Among men, excessive salt consumers comprised 85% of the salt preference group and 84% of the non-salt preference group. Among women, 88% of the salt preference group and 76% of the non-salt preference group were excessive consumers.
CONCLUSIONS: A simple questionnaire for salt preference was not effective in identifying excessive salt consumers. Convenient, reliable methods for the estimation of salt intake, such as the spot urine method, are recommended in place of the questionnaire.