Abstract
BACKGROUND: Excessive sodium intake is associated with high blood pressure and an increased risk of cardiovascular disease. However, reducing dietary salt has been challenging due to a lack of awareness and a high threshold in detecting saltiness. OBJECTIVES: The goal of this study is to evaluate the effectiveness of a combined intervention (intensive dietary education, food reformulation, environmental changes to facilitate salt reduction, and salt meter utilization), in comparison to standard education only, on salt intake and blood pressure. METHODS: A cluster randomized-controlled trial was conducted on 219 hypertensive adults aged 18 to 70 years in Uthaithani, Thailand. Participants were randomized 1:1 into the intervention group (n = 111) and the control group (n = 108). RESULTS: There were no differences in baseline characteristics between groups. The mean systolic and diastolic blood pressure was 143.6 and 82.1 mmHg and 142.2 and 81.4 mmHg in the intervention group, and the control group, respectively. The median 24-hour urinary sodium excretion was 3565 and 3312 mg/day, in the intervention and the control group, respectively. After 12 weeks, the change in systolic blood pressure was -13.5 versus -9.5 mmHg (P = 0.030) and diastolic blood pressure was -6.4 versus -4.8 mmHg (P = 0.164) in the intervention and control groups, respectively. Moreover, a reduction in 24-hour urine sodium excretion was observed [-575 versus -299 mg/day in the intervention and control groups, respectively (P = 0.194)]. The change in 24-hour urine sodium excretion was statistically significant and reduced from baseline in the intervention group (P = 0.004). The dietary salt intake was significantly improved and was statistically different between groups (P = 0.035). CONCLUSIONS: The combined intervention significantly decreased systolic blood pressure and showed a trend towards reduced urine sodium excretion in hypertensive patients. These comprehensive approaches may be beneficial in reducing blood pressure and salt intake in the community. CLINICAL TRIAL REGISTRATION: This trial was registered at Clinicaltrials.gov with the identifier NCT05397054. https://classic.clinicaltrials.gov/ct2/show/NCT05397054.