Fluid intake and blood pressure in children: the Salus per Aquam project.

BACKGROUND: Sodium intake is known to contribute to the development of hypertension, thus intake reduction is a cornerstone in the prevention and management of hypertension. The increase in renal sodium excretion might represent a further potential preventive and/or therapeutic opportunity. OBJECTIVE: To explore the working hypothesis that an increased fluid intake can improve renal sodium handling towards a decrease in blood pressure. METHODS: The SPA Project is a multicenter, observational, cross-sectional, cohort study investigating healthy children, aged 5-8 years as to sodium and fluid intake by means of urinary sodium and creatinine from multiple samples taken in different days in order to characterize them in lower/higher sodium and lower/higher fluid intake. Both SBP and DBP (by multiple office blood pressure measurements) were used as outcome measures. RESULTS: Three hundred and thirty-nine healthy, nonoverweight children (51.6% boys) with a median age of 5.7 years old (IQR: 5.3-6.2) participated in the study but only 223 could be analyzed. Among children with higher sodium intake, those introducing more fluids, showed a significantly lower blood pressure (both systolic and diastolic) compared with those with lower fluid intake: systolic 86.0 ±â€Š8.5 vs. 90.0 ±â€Š8.1 mmHg; P = 0.014 and diastolic: 53.8 ±â€Š4.9 vs. 58.6 ±â€Š6.6 mmHg; P < 0.0001. CONCLUSION: An increased fluid intake is associated with a reduced blood pressure possibly by increasing renal sodium excretion. We speculate that this simple, highly acceptable, inexpensive, and harmless measure might have a role in preventing and/or minimizing the epidemics of hypertension and of its related morbidities both in children and in adults.

Multiple office blood pressure measurement: a novel approach to overcome the weak cornerstone of blood pressure measurement in children. Data from the SPA project.

BACKGROUND: This contribution aims to report and analyze a novel approach for office blood pressure measurement in children. METHODS: Healthy children 5 to 8 years of age were eligible. After 5 minutes rest, 10 unattended blood pressure readings were taken at 3-minute intervals using a validated automated oscillometric device. After discarding outlier values (< 5th or > 95th percentile of the recorded values), the coefficient of variation and the mean of the 10 readings were calculated. The single readings #1 to #10 were compared with this elaborated average of the 10 measurements. RESULTS: Two hundred eighty-one healthy, non-obese children (137 females, 49%), median age 5.7 (IQR 5.3-6.1) years, were analyzed. The median coefficients of variation were 7% (IQR 5-9) for systolic and 4% (IQR 3-6) for diastolic blood pressure. The first 3 measurements were significantly different from the average, while the readings #4 to #10 were not. Based on the average, only nine subjects had a systolic or diastolic blood pressure > 90th centile (n = 3 > 95th percentile). CONCLUSIONS: Although most guidelines advise three blood pressure readings, these findings suggest that in children, office blood pressure measurement might be improved by including ten measurements. In situations of time constraints, the fourth blood pressure reading might be used as a reliable approximation.