Blood pressure response to dietary sodium restriction in healthy normotensive children

To examine the effect of dietary sodium restriction on blood pressure, 149 healthy, normotensive children (64 males, 85 females) participated in a study designed to lower Na intake and maintain Na excretion at less than or equal to 75 mmol/d or half usual intake for 12 wk. Na excretion was decreased during the study period in both males (112.9 +/- 6.3 vs 53.4 +/- 3.6 mmol, p less than 0.001) and females (91.1 +/- 3.2 vs 41.1 +/- 1.9 mmol, p less than 0.001). Changes in systolic blood pressure were not significant in either sex but females showed a decrease (p less than 0.05) in diastolic and mean arterial blood pressures. Because blood pressure in children is correlated with age and body size, multiple linear regression was used to adjust blood pressure levels for age and weight. These analyses yielded small but significant decreases in systolic, diastolic, and mean arterial pressure measurements. The blood pressure response was heterogeneous but this variable response could not be attributed to varying degrees of compliance within families. These results suggest that compliance with modest Na restriction does not consistently lower blood pressure in normotensive children.