[Zinc excretion in osteoporotic women]

Urinary zinc excretion was detected in 24 normal and 25 age matched osteoporotic women. The osteoporotic group was classified in two groups on the basis of bone mineral density (BMD) measurements. Urinary zinc excretion was 327 micrograms/g creat. in healthy subjects and 488 micrograms/g creat. in the "common porotic group". In the "trabecular porotic group" (decreased BMC with DEXA at the lumbar spine alone or together with the femoral neck, but with normal radius BMD) it was 455 micrograms/g creatinine while in the "cortical porotic group" (decreased BMD with SPA at the radius midshaft and/or all the sites measured) the zinc excretion was even higher, 588 micrograms/g creat. The difference between the normal and porotic groups was statistically significant, while within the porotic groups it was not, however the tendency was remarkable. A close significant correlation exists between BMC of radius and urinary zinc excretion. In the osteoporotic group the urinary calcium excretion was significantly higher, than in normal group (220.2 vs 145.2 mg/g creat, p < 0.01). The correlation between the urinary zinc and calcium excretion was not significantly statistically. Elevated urinary zinc excretion is characteristic in both types of involutional osteoporosis in women and therefore seems to be a potential new simple marker of bone resorption.