Urinary CTX in children from 6 to 10 years as a function of age and usual calcium intake.

MAROTTE C; PELLEGRINI G; LINARI M; PIAZZA N; SOMOZA J; RíO M; ZENI S

Buenos Aires

Congreso; XXIV Reunión Anual de la Asociación Argentina de Osteología y Metabolismo Mineral (AAOMM).; 2007

Asociación Argentina de Osteología y Metabolismo Mineral (AAOMM).

During normal growth, biochemical markers of bone turnover are higher than adults and their distribution parallel the pediatric growth curve being potential indices of skeletal growth. Beta C-telopeptide of collagen type I (bCTX) immunoassay is one of the most specific bone markers. According to The National Health and Nutrition Survey (2004-2006),  Argentina has a great percentage of population did not reach adequate Calcium (Ca) intake. Such nutritional inadequacy could affects peak bone mass acquisition and in normal healthy children can evaluate biochemically by Ca/Creatinine (Cr) ratio. The objective was to determine in healthy normal children urinary âCTX excretion related to gender, age and usual Ca intake. A total of 38  scholarship (24 girls and 14 boys) 6.0 to 10.3 years of age attending public schools (Vte.Lopez, Bs.As, Argentina) were studied. Food intake was assessed by a 24hs-recordatory and urine samples were collected under fasting conditions as the second morning void. Ca and âCTX (ELISA, Nordic Bioscience Diag.)  were expressed as a ratio to Cr excretion  (Ca/Cr: mg/mg and b-CTX/Cr: ug/mmol, respectively). The usual Ca intake was inadequate in 68% of children. The bCTX levels (mean ± SD) related to age and gender are shown in the table. Different letters indicates a p<0.05.     boys girls 6-<7 1346±438 1480±99 7-<8 1235±154 1335±517 8-<9 1069±239 1211±284 9-<10 1121±162 1226±188 10-<11 1546±40 2140±937                   Individual levels of âCTX correlated with Ca/Cr ratio (r=0.38; p<0.05) and such correlation increase when âCTX was plotted against ranges of Ca/Cr ratio (<0.05, 0.05-0.07, 0.07-0.10 and > 0.10) (r = 0.87, p<0.001). Conclusions: These results confirmed the high prevalence of Ca nutritional deficiency, even in children during growth. Since bCTX correlated with nutritional status it seems to be a promissory index of skletal growth and bone modelling to be used in cross-sectional screening studies of growth velocity. Supported by UBACyT, B703. Social Urgency  Project.