The relationship between body mass index and children’s presentations to a tertiary pediatric emergency department

The worrying increase of obesity and overweight in children, resulting in what is now an epidemic, has drawn a raising attention to the potential short and long-term health consequences. In fact, this phenomenon places a significant burden on healthcare system as evidenced by increased hospital admissions for obesity-related diagnoses, lengthened hospital stay [1], higher medication use [2], and a greater frequency of outpatient clinic visits and emergency department (ED) visits as well [3], and a major use of the ED than primary care settings for routine medical care [4]. The hospital ED is frequently a major source of primary care and it might become a not less important setting for the screening, counseling and prevention of children at excess body weight risk. This is backed up by a previous study that shows parents and their children are interested in receiving education addressing healthier lifestyle choices and they feel that the ED is an appropriate setting for such an intervention program as well [5].

Further to obesity, another crucial challenge for health system is the unintentional injury that represents the leading cause of childhood death and disability involving a huge drain health and societal resources as well [6].

The relationship between obesity and injury is a relatively new and interesting field; most of the results are in the direction to draw a link between the overweight/obesity and the occurrence of injury even if some aspects remain unclear and contradictory [7]. The obesity and injury are two entities not to be considered separately [8], but they may interact with multiple implications on the child outcome and induce the need of enhancing the health surveillance and implement specific plans for child health safety. The aim of study is to describe the characteristics of children admitted to ED in relation to Body Mass Index (BMI) and to investigate the relationship between BMI and injury at ED. Finally, we would emphasize and promote the role of the ED as a strategic setting for screening and counseling, for the early identification of co-morbidities related BMI ≥ 85th, and for a timely specialist referral of these children.

In our study, the prevalence of overweight and obesity was reported to be 20.2% and 13.5% respectively. The regional (Lazio) data from national surveillance obesity system shows a prevalence of overweight and obesity respectively 21.7% and 9.4% in 2014 [9]. Our data derived from the ED admissions of a tertiary hospital, although not representative of the Lazio region, and therefore not comparable, show high levels still worrying of excess of weight body in children.

Concerning epidemiological aspects, school age children were significantly more likely to be obese or overweight than adolescents. The early childhood is a key window period for delivering potentially effective preventive interventions because these years are a period of sensitivity to environmental influences and for the imprinting of health lifestyle [10]. Moreover, the excess of body weight in younger children is a highly predictive of obesity during adolescence and adulthood [11, 12]. Males were at a higher risk to be obese and overweight than females. This finding is in line with national and regional data [9]. No difference was showed between Italian and children with different ethnic background in contrast with a previous study conducted in Emilia Romagna Region in which the obesity resulted to be higher among Immigrants [13]. Probably in our region children from immigrant families abandon increasingly the originating eating habits to assimilate those of the host country [14]. The obese and overweight children were more likely to report a major number of visits for year at ED than patients with normal weight. Some studies have reported that excess body weight disorders involve an increased health care utilization, including ED visits¹ for both acute and routine medical care [4]. This phenomenon might be due to increase of obesity related comorbidities and consequently implicates a growing burden on healthcare system [15]. Nevertheless, this finding might to be due to confounding factors such as the family and social class that we did not considered in our analysis. Although in different settings from the one where we carried out our research and with weak association measures, some researcher reported that adjusting for demographics, socio-economic status, and chronic medical conditions, overweight or obese children still more frequently utilize the ED and outpatient clinic visits than under/healthy weight children [16]. Regarding causes of admission to ED, obese children were 34% less likely to present an injury. The possible relationship between obesity and injury is a relatively new interesting area of study, although the research in this area is limited for children. An association between obesity and various types of injury is described such as head and chest injuries in motor vehicle crashes [17], musculoskeletal injuries [18], ankle injuries [19], lower extremities [8]. Probably in our study children with BMI ≥ 85th were less likely to report an injury because of the type of involved injury mechanism. In fact, the fall/crash leisure-sport activities occurred more frequently in normal weight whereas the passive and static mechanism occurred mostly in BMI group ≥95th. The static and passive mechanism occurred mostly in obese children. These findings might indicate that normal weight children were exposed to a higher injury risk because of a major physical activity.

Among different types of injury, the fracture in school age individuals was over twice more likely if obese. There are few potential explanations for this data. First, age-related variation in mobility patterns should be considered. In fact, physical activity decreases with advancing age during childhood [20], because older children spend more time in sedentary behaviors including screen based (i.e. TV/video viewing, playing PC/video games etc.) and not screen based (i.e. texting, talking on the phone, etc.) [21], in particular overall sedentary time and individual sedentary behaviors increase during the transition from primary/middle to secondary/high school [22]. Finally, adolescents with obesity are supposed to present an increased bone density, similar to the pattern seen in obese adults [23].

Among different types of injury, the fracture occurred mostly in obese children but not significantly.

Children with obesity and overweight were more likely at risk for fracture at lower extremity (p < 0.05). This finding is in line with other studies that show the association between childhood obesity and increased risk of lower extremity fracture [23]. We might explain this finding by interaction of different potential factors. Firstly, the mechanical effect involves the overloading of bones, joints and soft tissues of the locomotor system on lower extremity influencing the alignment, structure, function of the hip, knee and foot [24], and consequently making more vulnerable the bone and joint of lower extremity to a potential risk of fracture and osteoarthritis [25]. Secondly, biomechanical factors might be considered, such as effects of excess body weight on the walking gait. In fact, children with excess weight disorders report a slower habitual or self-selected walking speeds with a concomitant reduction in step length and step frequency [26]. Thus, the reduced walking speed is typified by longer single support and double support phase durations along with a shorter swing phase [27]. The consequence of excess mass in children is an increase in both the absolute amount of force applied to the joint and the muscular force needed to move the additional mass during ambulation [27]. All these mechanical and biomechanical factors potentiate the effect of obesity on decreased bone density [28]. The bone density not only is affected by reduced physical activity or by bone development that is overtaxed by rapidly increasing weight [28], but we suppose that the vitamin D deficiency might play a decisive role in the pathogenesis of lower extremity fracture in children with BMI ≥ 85th. A previous cross-sectional study, carried out in our tertiary care center for obesity at Children’s Hospital Bambino Gesù, reports the vitamin D levels are inversely associated with nonalcoholic steatohepatitis and fibrosis in children with nonalcoholic fatty liver disease [29] that is a complication in children with obesity. Since this is the exclusive experience of a tertiary center, we might presume that children enrolled in this study might present characteristic similar to our cohort because both of them belong to the same hospital’s catchment area. This hypothesis might represent a powerful stimulus for a future cross sectional study in order to detect the potential rule of vitamin D in children with excess weight disorders presenting to our hospital with the lower extremity fracture.

A series of limitations should be considered in our study. First, as this study was carried out in a tertiary care center, its findings may not be extended to the general population. Second, the anthropometric parameters were measured by health providers instructed but we did not consider the error margin of measurement determined by the experience of the providers and by the compliance of the patient. Third, we did not consider chronic or underlying diseases and ongoing therapeutic treatments, thus we cannot exclude this potential confounder.

Our results indicate that school age children presenting to ED are more at risk of obesity and overweight than adolescents. Although obese children are less at risk of injury, probably because less prone to leisure-sport activities than normal weight counterpart, fractures occur more frequently in school age children with obesity. The childhood is a crucial temporal window for implementation of effective prevention strategy and to avoid future complications. Therefore, the ED might be a strategic setting for in the initial screening of these children and parental counseling, and for a timely specialist referral of these children, especially if school age, in order to guarantee further weight control-related interventions.