A study on the relationship between creatinine excretion and diet, physical activity and urinary volume was carried out on children from 5 to 12 years of age, observing usual life conditions. Qualitative analysis of diet revealed that possibly ingestion of creatine and creatinine ocurred with the noon meal. Regarding physical activity the data showed that the peak of activity occurred in the afternoon. The differences between average excretion of creatine corresponding to morning and afternoon periods were not statistically significant, the same being observed when diurnal and nocturnal averages of excretion were considered. On the other hand, the average volumes corresponding to diurnal and nocturnal periods revealed a significant difference, which suggests independence between creatinine excretion and urinary volume. However data show a positive significant correlation between creatinine excretion and urinary volume when individual results were considered.
Creatinine; Nutrition
