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Lithogenic risk factors in the urine of black and white subjects
Author(s) -
Whalley,
Fernando Moraes,
Shar,
Pretorius,
Meyers
Publication year - 1998
Publication title -
british journal of urology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.773
H-Index - 148
eISSN - 1464-410X
pISSN - 0007-1331
DOI - 10.1046/j.1464-410x.1998.00877.x
Subject(s) - urinary system , cystine , urine , creatinine , potassium , population , urinary calcium , medicine , calcium , sodium , calcium oxalate , chemistry , endocrinology , biochemistry , enzyme , environmental health , organic chemistry , cysteine
Objective To identify biochemical and dietary factors which may play a role in the low incidence of stone formation in the black South African population. Subjects and methods The study included 31 semi‐urbanized black and 29 urbanized white subjects. The protocol and modern laboratory techniques used to assess recurrent stone formers were followed. Urinary sodium, potassium, creatinine, calcium, phosphate and urate levels were measured, and urinary citrate, oxalate and cystine assessed. Results Black subjects ate a diet significantly higher in sodium ( P <0.04); there was no difference in serum levels but urinary sodium was significantly higher ( P <0.001) in black than in white subjects. Urinary potassium, calcium, citrate, phosphate and cystine were all significantly lower in black than in white subjects ( P <0.001 for the first four and P <0.03 for cystine). Conclusion Certain intrinsic factors in South African black subjects may account for their lower frequency of stone formation than in white subjects. Of these, the very low urinary calcium, decreased urinary cystine and different interactions between sodium and calcium/cystine are probably important.