Urate Excretion in Old Age

Serum urate levels were marginally higher in 11 nonbacteriuric elderly men (5.1 ± 1.8 mg%) than in 24 nonbacteriuric women (3.9 ± 1.6 mg%) of the same age. Bacteriuric elderly subjects (6 men, 7 women) had lower levels, these being closely similar in the two sexes (3.4 and 3.6 mg%, respectively). Significant reductions of C_In, C_creat, and TM_PAH were observed for bacteriuric men, but not for bacteriuric women. Further, the C_Urate: C_In ratio was higher in bacteriuric men and in women, bacteriuric or not, and was not depressed during the Tm_PAH periods. Increased daily intake of protein from 60 to 75 g was associated with higher serum urate levels in a larger group of subjects. We conclude that: (1) women, even at the age of 80 have a lower serum urate, related to a higher C_Urate; (2) bacteriuria increases the ratio C_Urate: C_In, particularly in men; (3) secretory mechanisms for urate differ from those of p-aminohippurate in the human, and (4) dietary protein overrides the effect of bacteriuria on serum urate without affecting the male:female ratio.