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Urolithiasis in Okinawa, Japan: A relatively high prevalence of uric acid stones
Author(s) -
HOSSAIN RAYHAN ZUBAIR,
OGAWA YOSHIHIDE,
HOKAMA SANEHIRO,
MOROZUMI MAKOTO,
HATANO TADASHI
Publication year - 2003
Publication title -
international journal of urology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 67
eISSN - 1442-2042
pISSN - 0919-8172
DOI - 10.1046/j.1442-2042.2003.00656.x
Subject(s) - uric acid , medicine , calcium oxalate , struvite , urinary system , calcium , oxalate , gastroenterology , phosphate , biochemistry , chemistry , inorganic chemistry
Aim: The aim of the present study was to investigate the composition of urinary tract stones in patients from Okinawa, the most southern island group of Japan. Methods: The study was conducted by 12 hospitals in Okinawa. A total of 1816 urinary tract calculi were obtained from 1816 patients (1323 males; 493 females). The patients had a mean age of 53 ± 15.3 years (mean ± SD). The calculi were examined to determine their chemical composition. Stone samples were analyzed by computed infrared spectrophotometer. Results: Pure stones comprised 58.4% of the total, with calcium oxalate stones accounting for 40% (21% monohydrate [whewellite]; 6.6% dihydrate [weddellite]; and 12.4% combined monohydrate and dihydrate stones), uric acid/urate stones for 9.6%, calcium phosphate stones for 5.1%, and struvite stones for 3.7%. The other 41.6% of the stones consisted of calcium oxalate mixed with other components. The male‐to‐female ratio was 2.7 : 1. Conclusion: In our series, calcium oxalate stones accounted for 81.6% of the urinary tract calculi, while uric acid/urate stones accounted for 15.8%. Uric acid stones, predominantly the anhydrous and/or dihydrate forms, showed a relatively high prevalence. Calcium oxalate stones, predominantly in the form of whewellite, showed a high prevalence among pure calculi; while the predominant combinations among mixed calculi were weddellite + calcium phosphate and whewellite + uric acid/urate.