Higher body weight in adolescence linked to greater bone area in adulthood
MedWire News: Being overweight in childhood is linked to having greater bone cross-section area in adulthood, according to findings published in Osteoporosis International.
Earlier studies have found both lower and normal or increased bone mass in overweight or obese children compared with nonobese children, note Kirsti Uusi-Rasi (The UKK Institute for Health Promotion Research, Tampere, Finland) and colleagues.
This apparent contradiction may stem from the inconsistencies noted with the dual-energy X-ray absorptiometry (DXA). This measuring system assumes that the body comprises two disparate tissue components (muscle/adipose tissue and bone tissue), which is not true with actual scans.
Peripheral quantitative computed tomography (pQCT) scans are more accurate, and studies using pQCT have found that overweight children had greater bone mass, larger bones, and higher bone density than healthy-weight children.
As adulthood obesity is also associated with increased bone mass and strength, Kirsti Uusu-Rasi (The UKK Institute for Health Promotion Research, Tampere, Finland) and colleagues set out to discover whether people who were who were overweight in childhood in fact had more robust bones in adulthood.
All registrants in the ongoing Young Finns Study (N=3386) were invited to undergo pQCT scanning; 832 ultimately participated and had their height, weight, and body mass index measured. The pQCT scans measured the radius of the non-dominant arm and left tibia, and investigators assessed total area (ToA), cortical area, stress strain index, and cortical density.
Uusu-Rasi and colleagues found that being overweight in childhood was associated with larger ToA in adulthood at both the radial and tibial bone sites. In women, greater body weight in early adolescence predicted denser trabecular bone density in adulthood, while in men, it predicted lower cortical density at the radius and tibia.
Although the overweight children had been taller than their peers, this difference was mostly erased when they became adults.
Therefore, the authors conclude that "body weight in early adolescence modulates bone phenotype in adulthood ." However, they note that there are many other factors that contribute to bone growth and several mechanisms that connect weight and bone development, including body composition, hormones, and nutrients.
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By Stephanie Leveene