Analysis of bone mineral density in urolithiasis patients.
BACKGROUND
The association between hypercalciuria and bone mineral density (BMD) has been already recognized. The aim of the present study is to relate BMD to age and sex and to evaluate the calcium metabolism and hypercalciuria-defined dietary or non-dietary category in patients with urolithiasis.


METHODS
The BMI of the L2-L4 lumbar vertebrae was measured in 310 renal stone patients (191 men and 119 women). Percent age matched score (%AMS), which is the percent ratio of measured BMD to the mean BMD of age-matched control subjects, was utilized for the appraisal of BMD. Low BMD groups were defined by lower than 90% of %AMS.


RESULTS
Low BMD was observed in 27.7% of urinary stone patients, which was not a significant difference to that of control subjects (23.5%) who were measured in the health examination. In male patients with urolithiasis, the frequency of patients in whom BMD had been apt to decrease since youth was high, but there was not a proven significant difference among the three age groups (20-39 years old, 40-59 years old and 60 years old or older). In contrast, for female stone patients, the frequency of low BMD markedly increased in patients aged 40 years or older, when menopause occurs. Furthermore, in female stone patients with hypercalciuria, the frequency of reduced BMD reached more than 40%. When the cause was non-dietary hypercalciuria (classified mainly on the daily amount of urinary calcium excretion after ingestion of calculus test diet), the frequency of reduced BMD reached 65% (P < 0.01).


CONCLUSIONS
In case female stone patients with non-dietary hypercalciuria become menopausal, not only the risk of recurrent lithiasis increases, but the possibility of developing osteopenia in the future also increases. Appropriate treatments for prophylactic effects on urolithiasis or osteopenia should be considered, as judged from BMD, diet, sex, urinary calcium excretion and other factors synthetically.
Tsuji
Hidenori
H
Department of Urology, Kinki University School of Medicine, Ohnohigashi Osakasayama Osaka, Japan. tsujihidenori@hotmail.com
Umekawa
Tohru
T
Kurita
Takashi
T
Uemura
Hirotsugu
H
Iguchi
Masanori
M
Kin
Kokai
K
Kushida
Kazuhiro
K
D015502:Absorptiometry, Photon; D000328:Adult; D000367:Age Factors; D015519:Bone Density; D002118:Calcium / Q000652:urine; D005260:Female; D006801:Humans; D015994:Incidence; D007669:Kidney Calculi / Q000453:epidemiology / Q000378:metabolism*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012737:Sex Factors
D002118:Calcium