Assessment of Biochemical Bone Turnover Markers and Bone Mineral Density in Thin and Normal-Weight Children

Abstract

Objective There is scant research examining the prevalence of thinness in early childhood, despite its potential negative consequences for health and development across the life course. The objective of this study was to assess bone status through measurement of bone mineral density and biochemical bone turnover markers, with special attention paid to carboxylated (c-OC) as well as undercarboxylated (uc-OC) forms of osteocalcin, in the groups of thin and normal-weight children. Design The study included 80 healthy prepubertal children (median age 7.0 years), who were divided (according to Cole's international cutoffs) into 2 subgroups: thin children ( n = 40, body mass index [BMI] = 13.5 kg/m) and normal-weight children ( n = 40, BMI = 16.1 kg/m). Bone mineral density (BMD) and bone mineral content (BMC) were assessed by dual-energy x-ray absorptiometry method. Serum concentrations of C-terminal telopeptide of collagen type I (CTX), total osteocalcin (OC), and c-OC, and uc-OC forms of osteocalcin were determined using enzyme-linked immunosorbent assays. Results In thin children, we observed higher levels of bone resorption marker CTX compared with normal-weight peers. Total osteocalcin concentrations were comparable in both groups of children; however, in thin children we observed higher median values of uc-OC (34.40 vs. 29.30 ng/mL, P < 0.05) and similar c-OC levels (25.65 vs. 28.80 ng/mL). The ratio of c-OC to uc-OC was significantly lower ( P < 0.05) in thin than in normal-weight children. Total BMD and BMC were significantly decreased ( P < 0.0001) in thin children compared with normal-weight peers (0.724 ± 0.092 vs. 0.815 ± 0.060 g/cm and 602.7 ± 159.2 vs. 818.2 ± 220.1 g, respectively). Conclusion Increased concentrations of CTX and uc-OC might lead to disturbances in bone turnover and a decrease in bone mineral density in thin children.

Bone formation and resorption markers at 7 years of age: Relations with growth and bone mineralization

“…Our results did not support previously described positive correlations between OC and height and weight [10, 14], between CTX and weight [14] and height [13, 38] or the finding of decreased OC values in obese when compared to healthy weight children [11, 12]. However, in accordance to our findings, a number of other studies have contributed with evidence of a lack of association between height, weight or BMI and OC [9, 10, 13, 14, 39, 44] and height or BMI and β-CTx [44]. Increased formation markers in taller and heavier children are likely reflecting greater growth velocity, inducing increased bone formation in response to greater mechanical strain [13, 32].…”

“…We found a positive correlation between OC and β-CTx, in agreement with findings in other samples of prepubertal children [17] but in contrast with one study including 5 to 10 year-old children [14]. Positive relationships between bone-specific formation and resorption markers are expected, and reflect the nature of bone turnover as a tightly regulated dynamic mechanism of formation and resorption [6].…”

“…These findings are consistent with the premise that bone markers reflect instantaneous metabolic activity and do not directly translate physical dimensions that result from the cumulative process of bone gain throughout several years [6]. In prepubertal children, some previous studies have also found no relationship between tALP, OC or β-CTx and whole body (WB) and LS BMC or BMD [14, 15, 35]. Other studies disclosed, however, consistent positive relationships between tALP and OC and WB and LS BMC, in boys [16] and between OC and CTX and WB and LS BMC/BMD, in both sexes [15, 17].…”

<p>Soluble Biomarkers of Osteoporosis and Osteoarthritis, from Pathway Mapping to Clinical Trials: An Update</p>

“…Complementarily, low grade inflammation related to obesity promotes adipogenesis in the detriment of osteoblastogenesis and calcium absorption, increasing the risk of fractures and osteoporosis. [42][43][44] In a study presented by Ambroszkiewicz et al 45 higher CTX-I levels indicated a defective bone formation in thin children, compared to normal-weight peers. Moreover, the ratio of the carboxylated OC/undercarboxylated OC, as well as the BMD were significantly lower in thin children when compared to the normal-weight group.…”

Effect of type of sport, weekly physical exertion and body mass index on values of bone turnover markers in elite female athletes

“…Ovo je ukazalo da negativan energetski balans, praćen smanjenjem vrijednosti BMI i vjerovatno smanjenjem procenta mišićnog tkiva, ima manji osteogeni efekat, smanjenim opterećenjem sopstvenom težinom, a vjerovatno i smanjenim efektom trakcije od strane mišićnog tkiva. Do sličnog rezultata je došla i nedavna studija Ambroszkiewicz-a i saradnika [33] kojom je utvrđeno da eumenoreične djevojke adolescentne dobi koje imaju manji BMI imaju veće vrijednosti markera razgradnje kosti CTX, a manje vrijednosti osteokalcina. Slične tvrdnje je pokazala i nedavna studija Thralls-a i saradnika [34] u kojoj su potvrdili da smanjene vrijednosti opštih antropometrijskih indeksa (BMI I IBW) mogu biti prediktori smanjene vrijednosti BMD kod aktivnih sportistkinja.…”