Urinary melamine and adult urolithiasis in Taiwan.
BACKGROUND
This study aims to investigate the association between urinary melamine concentration and the risk of urolithiasis in adult.


METHODS
From 2003 to 2007, 11 and 22 patients diagnosed with upper urinary tract uric acid urolithiasis and calcium urolithiasis, respectively, were recruited from Kaohsiung Medical University Hospital. For comparison, we randomly collected 22 sex- and age-matched subjects who come to the same hospital for regular health check-up at the same period of time. Urinary melamine concentration was measured by the method of triple-quadrupole liquid chromatography tandem mass spectrometry (LC-MS/MS). Wilcoxon rank sum test was used to compare the urinary melamine concentrations in uric acid urolithiasis patients with controls as well as in calcium urolithiasis patients with controls. FDR (false discovery rate) was used to correct the p-values for two comparisons.


RESULTS
Subjects with uric acid urolithiasis (median: 0.50 vs 0.06microg/mmol creatinine, Wilcoxon test: FDR_p=0.024) and with calcium urolithiasis (median: 0.14 vs 0.06, FDR_p=0.024) had significantly higher urinary melamine concentration than controls. Based on the ROC curves, subjects whose melamine levels were over 0.262 and 0.037microg/mmol creatinine, respectively, might have significant risks to have uric acid and calcium urolithiasis.


CONCLUSIONS
This preliminary study suggests that exposure to even low-dose melamine-related products still have the potential to develop both uric acid and calcium urolithiasis in adults.
Wu
Chia-Fang
CF
Graduate Institute of Occupational Safety and Health, Kaohsiung Medical University, Kaohsiung, Taiwan.
Liu
Chia-Chu
CC
Chen
Bai-Hsiun
BH
Huang
Shu-Pin
SP
Lee
Hei-Hwa
HH
Chou
Yii-Her
YH
Wu
Wen-Jeng
WJ
Wu
Ming-Tsang
MT
D000328:Adult; D002118:Calcium / Q000378:metabolism; D016022:Case-Control Studies; D006801:Humans; D007668:Kidney / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012306:Risk; D013624:Taiwan; D014227:Triazines / Q000652:urine*; D014527:Uric Acid / Q000378:metabolism; D052878:Urolithiasis / Q000378:metabolism / Q000503:physiopathology / Q000652:urine*
D014227:Triazines; D014527:Uric Acid; C011907:melamine; D002118:Calcium