Childhood obesity as a risk factor for bone fracture: A mechanistic study


  • Role of the Sponsor: The funding organization had no role in the design and conduct of the study, in the collection, management, analysis, and interpretation of the data, or in the preparation, review, or approval of the manuscript.

  • Disclosure: Dr. David B. Allison has, anticipates, or has had financial interests with the Frontiers Foundation; Vivus, Inc.; Kraft Foods; University of Wisconsin; University of Arizona; Paul, Weiss, Wharton & Garrison LLP; and Sage Publications. The rest of the authors have no conflict of interest in relation to this study.

    Funding agencies: This research was supported by the Nutrition Obesity Research Center (NORC) at the University of Alabama at Birmingham, through a grant from the National Institutes of Health (No. P30DK056336).

Correspondence: Jong-Eun Kim (



To investigate the risk of bone fracture sustained by obese children exposed to falls. The bone fracture risk of obese children would be greater than that of their nonobese counterparts was hypothesized.

Design and Methods

Finite element-based computational models for children that reflected various levels of obesity by varying body mass and the thickness of the subcutaneous adipose tissue layer was developed. The models took account of both the momentum effect of variation of body mass and the cushion effect of variation of soft tissue thickness and examined these two contradictory effects on pelvic bone fracture risk through a set of sideways fall simulations with a range of impact speeds.


The critical impact speed that yielded pelvic bone fracture decreased as the levels of obesity increased, which meant that the momentum effect of a greater body mass took precedence over the cushion effect of the soft tissue layer.


The result suggests that obese children have a greater risk of pelvic bone fracture than do their nonobese counterparts in sideways falls. A further implication is that current child safety devices, systems, and regulations will need to be revisited as the prevalence of child obesity increases.