The First Report on the Frequency of Asymptomatic Proteinuria in Iranian School‑aged Children

Proteinuria is a well‑known indicator of renal dysfunction. In this study, we evaluated the frequency of proteinuria in a sample of healthy Iranian elementary school students using both dipsticks and urine albumin‑to‑creatinine ratio (UACR) methods.

This cross‑sectional study was performed on 478 school students aged 7–9 years who were selected by multistage random cluster sampling from Isfahan city, Iran. A clean midstream first‑morning urine sample was obtained from each subject. Urine samples were examined by dipstick method, and accordingly, they were reported as negative; trace; 1+; 2+; 3+; and 4+. UACR was determined in samples with positive dipstick proteinuria (defined as trace or greater).

This study included 478 students (42.8% boys), with mean age of 7.0 ± 0.4 years. Positive dipstick was detected in 124 (25.9%) cases. The frequency of positive dipstick proteinuria was significantly higher in the girls than boys (29.6% vs. 20.9%, respectively; P = 0.04). In cases with a positive dipstick, 10 (2.1%) cases had UACR 30–300 mg/g. The frequency of UACR of 30–300 mg/g was 1.4% and 2.5% in boys and girls, respectively. There was no significant difference in the frequency of UACR 30–300 mg/g in terms of gender (P = 0.4). None of the subjects had UACR above 300 mg/g.

While the frequency of asymptomatic proteinuria varies widely across different studies, we found a higher rate of proteinuria in Iranian children. Cost‑effectiveness analyses are needed to justify large screening program for detecting asymptomatic proteinuria, as a cardinal manifestation of kidney disease, in Iranian children.