ObjectiveTo investigate the risk of bone fracture sustained by obese children exposed to falls. We hypothesized that the bone fracture risk of obese children would be greater than that of their nonobese counterparts.Design and MethodsWe developed 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. 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.ResultsThe 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.ConclusionsThe 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.

Objective To investigate the risk and injury severity on the regional body (head, neck, and chest) of obese children in frontal motor vehicle crashes. Design and Methods No physical surrogates (i.e., crash dummies) for obese children are available and experiments on pediatric cadavers are generally not feasible. Therefore, we developed computational models of obese children using medical imaging processing and state-of-the-art modeling techniques. A hybrid modeling technique was used to integrate finite element model for torso fat layer into the standard multibody model to represent various levels of obese children for 3- and 6-year-old age group. The models were used to investigate injury severity under various crash scenarios through model simulations. Results The head injury criterion and chest acceleration were observed to increase as body mass index (BMI) increased. Meanwhile, no such correlations were found between BMI and neck injury and chest deformation. Forward head and torso excursions were observed to increase as obesity increased, owing to the momentum effect of greater body mass. Conclusions Obese children appear to have greater risks of the head and chest injuries than do their non-obese counterparts in frontal motor vehicle crashes, owing to higher head and chest accelerations induced by greater body excursion.

According to current definitions [1], individuals ages 2 to 18 years are determined to be overweight (≥ 85th and < 95th percentile [of prior population distributions]) or obese (≥ 95th percentile) based on U.S. age- and sex-specific body mass index (BMI; kg/m 2) charts updated by the Centers for Disease Control and Prevention (CDC) in 2000 [2]. The prevalence of being obese among children has increased over the last several decades and is a major public health concern. A recent survey [3] indicated that 16.3% of children and adolescents aged 2 through 19 years were at or above the 95 th percentile of the BMI-for-age growth charts.