MedWire News: Both lean body mass (LBM) and total fat mass (TFM) should be considered when determining bone mineral content (BMC) and bone mineral density (BMD) in children, demonstrate study findings from Iceland.
“Our study showed that total BMC was positively associated with both bone area and LBM but negatively associated with TFM,” report Hrafnkelsson Hannes (University of Iceland, Reykjavik) and co-workers.
“This means that two children with the same LBM and bone area would have different total BMC, depending on their TFM; the one with more TFM would have lower total BMC.”
The researchers examined the relationships among gender, height, LBM, TFM, and lumbar vertebrae and hip BMD and BMC in 211 7-year-old children attending six schools in Reykjavik.
As reported in the journal Bone, BMD and BMC were positively associated with the children’s gender, height, and LBM. However, TFM correlated positively with BMC but not BMD in total body and lumbar vertebrae.
Furthermore, in multivariate analysis, bone area and LBM were positively associated with BMC at the hip and total body, while TFM was negatively associated with BMC. This explained 88% of variance in total body BMC and 74% of variance in hip BMC, the researchers note.
Meanwhile, LBM was positively correlated with total body BMD, whereas TFM was negatively associated. Neither height nor gender were significantly associated with total BMC or BMD.
“Because weight includes TFM mass and LBM, two factors that have different association with total BMC in our cohort, we conclude that they should be looked at separately, and that both have clinical significance when interpreting total BMC,” Hannes et al write.
“Otherwise, overweight children would be estimated to have more BMC than expected."
The team concludes: “Our study emphasizes the importance, when looking at factors associated with bone mass, of remembering that children are not ‘small adults’ and fat mass may play different roles in children and adults.”
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2009
Free abstract
