The ratios of 24-hour urinary creatinine excretion and arm muscle area of all the boys in 9 age groups Were about 0.32. There are significant correlations between urinary creatinine values and arm muscle diameter and arm muscle area.

• 各年龄组24小时尿肌酐含量与上臂肌肉面积的比值均在0.；32左右。 尿肌酐值与上臂肌肉直径和面积高度相关。