Investigation on hyperuricemia in children with obesity or various pediatric disorders.

The present study aims at investigating the frequency and characteristics of hyperuricemia in both obese and sick children. First, we established our own reference values for serum uric acid (UA), since UA values are highly dependent upon age. In the analysis of 328 samples consisting of six different age groups: <1, 1-3, 4-6, 7-9, 10-12, and 13-15 years, the mean values for UA were found to increase significantly with an increase of age. A significant sex difference was observed only in the age group of 13-15 years. Hyperuricemia was defined as the values over the mean value plus 2 standard deviations for each age group. Next, we examined the frequency of hyperuricemia in 1,687 obese children aged 6-15 years and its relation to metabolic syndrome (MetS). A total of 328 children (19.4%) were found to have hyperuricemia. Among them, 98 children (29.9%) had MetS, whereas 197 (14.5%) out of 1,359 children without hyperuricemia had MetS. Finally, the frequency of hyperuricemia in sick patients was investigated using 13,675 samples from 9,405 patients. Hyperuricemia was seen in 348 (3.7%) patients after excluding redundant samples. The number of patients with hyperuricemia was higher in males than in females. The most common disorder causing hyperuricemia was gastroenteritis, followed by respiratory tract infection and cardiac diseases. This first comprehensive study of childhood hyperuricemia is useful for considering its relationship with hyperuricemia and life-style-related disorders occurring in adulthood.