Validation of an easy questionnaire on the assessment of salt habit: the MINISAL-SIIA Study Program

BACKGROUND/OBJECTIVES: The aim of the present study was to validate a short questionnaire on habitual dietary salt intake, to quickly and easily identify individuals whose salt consumption exceeds recommended levels. SUBJECTS/METHODS: A total of 1131 hypertensive subjects participating in the MINISAL-SIIA study were included in the analysis. Anthropometric indexes, blood pressure, and 24-h urinary sodium excretion (NaU) were measured. A fixed-sequence questionnaire on dietary salt intake was administered. RESULTS: NaU was significantly associated with scores, with a linear association across categories (p for trend <0.0001). In addition, participants who achieved a total score above the median value (eight points) had significantly higher NaU than those whose score was below median (p < 0.0001). In the total sample, the prevalence of "high NaU" (NaU > 85 mmol/day) and "very high NaU" (NaU > 170 mmol/day) was 86 and 35%, respectively. The score of the questionnaire had a significant ability to detect both "high NaU"-with a specificity of 95% at the score of 10 points-and "very high NaU"-with a specificity of 99.6% at score of 13 points. CONCLUSIONS: The main results of the study indicates that a higher score of this short questionnaire is distinctive of habitual high salt consumption in hypertensive patients.