Self-monitoring of urinary salt excretion as a method of salt-reduction education: a parallel, randomized trial involving two groups.

OBJECTIVE: The present study aimed to evaluate salt-reduction education using a self-monitoring urinary salt-excretion device. DESIGN: Parallel, randomized trial involving two groups. The following parameters were checked at baseline and endline of the intervention: salt check sheet, eating behaviour questionnaire, 24 h home urine collection, blood pressure before and after urine collection. SETTING: The intervention group self-monitored urine salt excretion using a self-measuring device for 4 weeks. In the control group, urine salt excretion was measured, but the individuals were not informed of the result. SUBJECTS: Seventy-eight individuals (control group, n 36; intervention group, n 42) collected two 24 h urine samples from a target population of 123 local resident volunteers. The samples were then analysed. RESULTS: There were no differences in clinical background or related parameters between the two groups. The 24 h urinary Na:K ratio showed a significant decrease in the intervention group (-1·1) compared with the control group (-0·0; P=0·033). Blood pressure did not change in either group. The results of the salt check sheet did not change in the control group but were significantly lower in the intervention group. The score of the eating behaviour questionnaire did not change in the control group, but the intervention group showed a significant increase in eating behaviour stage. CONCLUSIONS: Self-monitoring of urinary salt excretion helps to improve 24 h urinary Na:K, salt check sheet scores and stage of eating behaviour. Thus, usage of self-monitoring tools has an educational potential in salt intake reduction.

Comparison of a salt check sheet with 24-h urinary salt excretion measurement in local residents.

The salt check sheet developed by Tsuchihashi et al. is widely used in general practice to assess salt intake and the associated diets. However, its appropriateness for the general population has not been assessed alongside 24-h urinary salt excretion monitoring. Therefore, in local residents, we analyzed the correlation between check-sheet scores and 24-h urinary salt excretion levels to determine the appropriateness of the check sheet. We asked 176 local residents to complete the salt check sheet and provide urinary samples; the latter were obtained using a proportional sampling method over a 24-h period. One hundred and forty subjects completed the study (men/women: 23/117, mean±s.d. age: 52.7±19.6 years, blood pressure: 122.3±18.0/74.3±11.1 mm Hg), of whom 51 (36.4%) had hypertension. The total salt check-sheet scores were widely distributed (mean±s.d.: 11.1±4.2 points, range: 0-22 points), and the subjects were divided into the following groups on the basis of salt levels: 29.3% were 'low' (0-8 points), 42.8% were 'medium' (9-13 points), 23.6% were 'high' (14-19 points) and 4.3% were 'very high' (>20 points). The mean 24-h urinary salt excretion level was 8.5±3.3 g. The subjects with higher salt-intake levels tended to have increased 24-h urinary salt excretion levels, with significant differences between the three groups ('low' vs. 'medium' vs. 'high to very high' salt levels: 7.6±2.9 g vs. 8.4±2.8 g vs. 9.6±4.2 g, respectively; P=0.03). The total salt check-sheet scores significantly correlated with the 24-h urinary salt excretion levels (r=0.27; P<0.01). Thus, the salt check sheet is applicable for the general population.