Relationship between twenty-four hour urinary creatinine excretion and weight, or weight and height of Japanese children.

Twenty-four hour (24-h) urinary creatinine excretion was measured and correlated with anthropometric measurements (height, weight, skinfold thickness, and arm muscle area (AMA)) in 119 healthy Japanese children, aged 2 to 18 years. The results indicated highly significant correlations between creatinine excretion and age (r = 0.88 for boys, 0.90 for girls), height (r = 0.91, 0.88), weight (r = 0.96, 0.94), and AMA (r = 0.91, 0.70). In the multiple regression estimation, weight alone, or weight and height, accounted for most of the variation in 24-h creatinine excretion (r2 = 0.93 for boys, 0.89 for girls), and the addition of other variables did not further improve the estimation.