Urinary calcium is a determinant of bone mineral density in elderly men participating in the InCHIANTI study.
BACKGROUND
It is generally acknowledged that calcium excretion is a determinant of bone mineral density. Since data confirming this hypothesis are not conclusive, the present study evaluates the relationship between calcium excretion and volumetric bone mineral density (vBMD) in a sample of general population mostly composed of elderly subjects.


METHODS
This relationship was studied in 595 subjects in good health (M/F 302/293), selected from the InCHIANTI population, an epidemiologic survey on aging in Tuscany (Italy). Of these subjects, 432 (72.6%) were 65 years old or older. Trabecular and cortical apparent vBMDs were measured by peripheral quantitative computed tomography at right tibia and standardized to age and body mass index (BMI) in each gender (z-score).


RESULTS
Men in the highest tertile of calcium excretion had significantly lower trabecular vBMD, and were more likely to have a trabecular z-score of -1 or less. These results were confirmed in men older than 64 years, but not in women and younger men. Sodium excretion and 25-hydroxycolecalciferol (25(OH)D) were greater in men and women in the highest tertile. No differences among tertiles were observed for cortical vBMD, circulating levels of interleukin-1beta and interleukin-6, and intake of principal nutrients and calcium. The lower levels of vBMD z-score were confirmed in men in the highest tertile of calcium excretion, standardized to creatinine clearance, sodium excretion, plasma calcium, and logarithm of circulating 25(OH)D, and resulted to be associated with calcium excretion at multiple regression analysis in men.


CONCLUSIONS
High calcium excretion is associated with a decreased trabecular BMD in elderly men and may predispose men to trabecular bone loss.
Vezzoli
Giuseppe
G
Division of Nephrology Dialysis and Hypertension, IRCCS San Raffaele Hospital, Postgraduate School of Nephrology, Vita Salute University, Milan, Italy. vezzoli.giuseppe@hsr.it
Soldati
Laura
L
Arcidiacono
Teresa
T
Terranegra
Annalisa
A
Biasion
Rita
R
Russo
Cosimo Roberto
CR
Lauretani
Fulvio
F
Bandinelli
Stefania
S
Bartali
Benedetta
B
Cherubini
Antonio
A
Cusi
Daniele
D
Ferrucci
Luigi
L
D000328:Adult; D000368:Aged; D015519:Bone Density; D002118:Calcium / Q000652:urine*; D003404:Creatinine / Q000378:metabolism; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D012964:Sodium / Q000652:urine; D013977:Tibia / Q000000981:diagnostic imaging / Q000378:metabolism; D014057:Tomography, X-Ray Computed
D012964:Sodium; D003404:Creatinine; D002118:Calcium