BLOOD PRESSURE IN RELATION TO INTERACTION BETWEEN DIETARY SODIUM INTAKE AND SERUM URIC ACID IN CHILDREN AND ADOLESCENTS WITH PRIMARY HYPERTENSION

Abstract

Abstract Objective: We investigated ambulatory blood pressure in relation to interaction between dietary sodium intake and serum uric acid in children and adolescents with primary hypertension. Design and method: The study subjects were in the age range from 10 to 24 years, admitted in Ruijin Hospital because of hypertension. Ambulatory blood pressure monitoring was performed during hospitalization using SpaceLabs 90217 monitors. We collected 24-hour urine for measurements of sodium excretion. We measured serum uric acid concentration with a blood chemistry autoanalyzer, and defined hyperuricemia as a serum uric acid concentration of at least 5.5 mg/dl. Our analysis was restricted to those with primary hypertension (n = 580). Results: The prevalence of hyperuricemia was 48.7%, being higher in male (n = 252) than female (n = 31, 54.9% vs 25.4%) and in untreated (n = 84) than treated patients (n = 199, 56.4% vs 46.1%). Ambulatory blood pressure did not differ across the quartile distributions of urinary sodium excretion (P > = 0.05), but was significantly (P < = 0.04) higher in patients with hyperuricemia than those without for all components, except 24-hour and daytime systolic blood pressure (P > = 0.15). In multivariable regression analysis adjusted for age, sex, body mass index, current smoking and alcohol intake, there was a significant (P < = 0.03) interaction between urinary sodium excretion and serum uric acid in relation to 24-hour systolic and diastolic blood pressure. Indeed, in the presence of hyperuricemia, 24-hour systolic/diastolic blood pressure was 2.2/1.1 mm Hg higher with 100 mmol increase in urinary sodium excretion. Conclusions: Dietary sodium intake interacts with serum uric acid to be associated with ambulatory blood pressure.