Journal of Safety Research

Journal of Safety Research

Volume 58, September 2016, Pages 49-56
Journal of Safety Research

Injury risks in schoolchildren with attention-deficit/hyperactivity or autism spectrum disorder: Results from two school-based health surveys of 6- to 17-year-old children in Sweden

https://doi.org/10.1016/j.jsr.2016.06.004Get rights and content

Highlights

  • We studied correlations between ADHD and ASD and injury risks in Swedish children.

  • Relative risks were estimated using regression models to account for confounding.

  • We found evidence of increased risks in children with ADHD, but not those with ASD.

Abstract

Introduction

Injuries are one of the leading causes of death and disability among children in Sweden and attention-deficit/hyperactivity disorder (ADHD) has previously been associated with an increased risk of injury in pediatric populations elsewhere in the world. Current evidence regarding the possible link between autism spectrum disorder (ASD) and injury risk appears limited, even though some potentially risk-increasing symptoms overlap. The purpose of this study was thus to study the association between both ADHD and ASD concerning the risk of injury among Swedish schoolchildren.

Methods

Two samples were used: a population-based register study containing data from 18,416 children ranging from the ages of 6–17 years collected by school nurses during 2012/2014 (Survey A), and a national cross-sectional study of 3202 ninth-grade children (~ 15 years old) collected from 92 schools in 2011 (Survey B). The data were analyzed using χ2-tests and log-binomial generalized linear models to obtain risk ratios (RR), comparing cases reportedly affected by ADHD or ASD to unaffected controls.

Results

After adjusting for confounders, ADHD was associated with a 65% increased risk of injury (RR 1.65 [95% CI: 1.32–2.05] in Survey A, and a 57% increased risk of injury (RR 1.57 [95% CI: 1.27–1.95]) in Survey B. ASD was not significantly associated with any differences in injury risk (RR 0.81 [95% CI: 0.57–1.14]).

Conclusions

The results indicate that there is an elevated injury risk among Swedish schoolchildren with ADHD but not for children with ASD. Future studies should focus on causal mechanisms mediating the association between ADHD and injuries in order to facilitate injury prevention strategies.

Practical applications

Parents and teachers of schoolchildren with ADHD should be made aware of the elevated injury risks associated with the diagnosis. Safety experts and injury control professionals should consider the development of specialized prevention strategies in order to reduce these risks.

Introduction

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are the two most common diagnoses of neurodevelopmental disorders in the world. About 5% of the Western world's child and adolescent population suffer from ADHD (Polanczyk, de Lima, Horta, Biederman & Rohde, 2007). ASD, while not as common as ADHD, affects 0.6–1.0% of the population (Elsabbagh et al., 2012). Both diagnoses are more common in boys than in girls (Wittchen et al., 2011). ASD commonly causes problems with social interaction, communication, and restricted and stereotyped patterns of interests and behaviors. ADHD is usually characterized by persistent symptoms of inattention, hyperactivity, and impulsiveness. The hyperactivity, in combination with issues with attentional and inhibitory control, may interfere with functioning at home, at school and with school performance, or with social relations (American Psychiatric Association, 2013). Evidence also suggests that ADHD and ASD symptoms often co-occur, with studies reporting a prevalence of overlap from 14 to 78% (Simonoff et al., 2008, Gargaro et al., 2011).

Both disorders can have long-term negative impacts on academic achievement, work performance, and mental health and have been associated with an increased risk of substance abuse and the development of antisocial personality disorder (Brook et al., 2013, Crump et al., 2013, De Alwis et al., 2014, Scholtens et al., 2013). There is also a wide range of evidence linking ADHD to an increased risk of mortality and morbidity stemming from accidental injuries (see e.g. Dalsgaard et al., 2015, Hurtig et al., 2016). Some research has also been conducted regarding the causal mechanisms behind this association. For instance, Stavrinos et al. (2011) provided evidence that executive dysfunction (i.e., issues with processes that enable physical, cognitive, and emotional self-control) mediates the entire difference in safe pedestrian crossing behavior between children with and without ADHD. Children with ASD also exhibit some of the same executive dysfunctions as children with ADHD (Corbett, Constantine, Hendren, Rocke & Ozonoff, 2009), which could suggest that they are also at higher risk of injury. However, apart from a body of literature detailing self-injurious behaviors in people with ASD (see e.g. Murphy et al., 2005), considerably less research has been conducted regarding ASD and injury risk in general. The results from these studies are ambiguous, showing negative (Furlano, Bloechliger, Jick & Meier, 2014) and positive (Cavalari & Romanczyk, 2012) associations, along with heterogeneity in the risk of different injury types (Schlenz, Carpenter, Bradley, Charles & Boan, 2015). Although symptoms commonly associated with ADHD prevalently appear in children with ASD (Lecavalier, 2006), other possible mediating factors in the relationship between these neurodevelopmental disorders and injuries may vary between them, so a theoretical connection between ASD and injury is far from self-evident. For instance, adolescents with ADHD have been documented to exhibit risk-taking behaviors in terms of substance abuse, gambling, and risky sexual behaviors (see e.g. Flory et al., 2006, Lee et al., 2011, Groen et al., 2013).1 There is also evidence linking ADHD to the anticipation of less severe consequences of risky behavior compared to their unaffected peers (Bruce et al., 2009, Farmer and Peterson, 1995). Taking this into consideration along with the fact that people with ASD are less likely to attempt to enter into social relationships than people with ADHD due to the core social deficiencies that characterize the disorder, there may be reason to believe that even though some symptoms may affect injury risks overlap between the two diagnoses, exposure to injury risks may differ largely due to peer effects, social behavioral patterns, and interests.

Furthermore, there is some ambiguity in the literature regarding the role of specific behavioral factors commonly associated with these disorders and injury risk. While hyperactivity has long been hypothesized to be a significant injury risk factor in children, early critical reviews of the literature have suggested that aggression and antisocial behavior, rather than hyperactivity, may be stronger independent predictors of injury (Davidson, 1987, Wazana, 1997). However, a more recent prospective study has found evidence of the contrary (Spinks, Nagle, Macpherson, Bain & McClure, 2008). Nevertheless, aggression is also a common symptom in children with ASD (Kanne & Mazurek, 2011), but as far as we know, no study has reported the possible mediating effects of aggression on injury risk in children diagnosed with this disorder. Also, studies including behavioral and family predictors of injury have also showed signs that family factors, such as living with a single parent, are more important than behavioral factors, including hyperactivity and aggression (Dudani, Macpherson & Tamim, 2010).

Injury is the leading cause of death and hospitalization among Swedish adolescents (Lundqvist, Tennlind, Schyllander & Stenbäck, 2012), and while evidence of an increased injury risk among children with ADHD is starting to accumulate, this association has to our knowledge not yet been studied in a Swedish setting with regard to children. Current evidence regarding the possible link between ASD and injury risk also appears limited, and as far as we know, no previous studies have analyzed the risk of injury among ADHD and ASD children in the same sample and thus being able to control for the same confounding variables. The purpose of this study was therefore to study the association between both ADHD and ASD concerning the risk of injury in a Swedish setting, using comparable cross-sectional data from two different samples of schoolchildren: a nationally representative sample of ninth-graders and a population-based data collected by school nurses in the county of Värmland, Sweden.

Section snippets

Data collection and study population

We used data from two different surveys, denoted below as Survey A and B. The questionnaires are similar in terms of questions asked, albeit with a few differences of consequence for the interpretation of our study. Firstly, data from Survey A are in part guardian and self-reported, while data from Survey B are entirely self-reported.

Results

Table 1 displays the results from two-way cross-tabulations of the ADHD and ASD variables along with the injury outcome variables from both surveys. As we can see there, the prevalence of ADHD was 3.45% in Survey A and 3.2% in Survey B, and the prevalence of ASD was 2.4% in Survey A. Overall, 6.1% of the respondents in Survey A had reportedly sustained a serious injury during their lifetime. Among those affected by ADHD or ASD, the reported prevalence of injury was 13.1% and 7.7%, respectively.

Discussion

The results of this study support previous findings that ADHD is associated with an increased risk of injury among children and adolescents, while suggesting that ASD is not associated with higher overall injury risks. For ADHD, we found associations of similar magnitude in both samples, an effect size that also corresponds well with previous studies linking ADHD to higher risk of injury. One hypothesis regarding the lack of an elevated injury risk in ASD children may be due to similarities in

Conclusions

This study indicates that there is an elevated injury risk among Swedish school-aged children with ADHD compared to unaffected controls, and that there is no apparent connection between ASD and the risk of injury. Future studies should focus on factors mediating the relationship between ADHD and injury in order to further facilitate injury prevention strategies.

Practical applications

Parents and teachers of schoolchildren with ADHD should be made aware of the elevated injury risks associated with the diagnosis. Safety experts and injury control professionals should consider the development of specialized prevention strategies in order to reduce these risks. While stimulant medication may serve as a part of the puzzle, innovative strategies that target specific risk factors other than those alleviated by medication may be needed as well.

Conflicts of interest

The authors have no conflicts of interest to declare.

Acknowledgments

The authors gratefully thank Finn Nilson and Ragnar Andersson for their helpful comments on an earlier version of this paper, and the County Council of Värmland for supplying the ELSA dataset. This study was funded by a research grant from the Swedish Civil Contingencies Agency (grant number 2013-4176), which we are also grateful for. The funding source had no role in the design of the study, the analysis and interpretation of the data, or the writing of, nor the decision to publish, the

Carl Bonander is currently pursuing his PhD degree at the Centre for Public Safety at Karlstad University. While his thesis project involves methods for inferring causality in non-experimental evaluations of injury control interventions, he also works on several projects involving the study of injury risks in e.g. the home and leisure environment, and risk factors for such injuries. His teaching responsibilities at Karlstad University involve master-level courses in e.g. injury epidemiology and

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  • Cited by (0)

    Carl Bonander is currently pursuing his PhD degree at the Centre for Public Safety at Karlstad University. While his thesis project involves methods for inferring causality in non-experimental evaluations of injury control interventions, he also works on several projects involving the study of injury risks in e.g. the home and leisure environment, and risk factors for such injuries. His teaching responsibilities at Karlstad University involve master-level courses in e.g. injury epidemiology and public policy evaluation.

    Linda Beckman, PhD, is a senior lecturer in Public Health at Karlstad University at the Department of Public Health Science. Her primary research interests include children's mental health analysis with particular interest in children with neurodevelopmental conditions as well as children involved in, and exposed to peer victimization.

    Staffan Janson is a professor emeritus in Public Health at Karlstad University and guest professor in Pediatrics at Uppsala University, Sweden. His main research has been about child safety and child abuse. He has been heading the iterated national Swedish studies on child maltreatment and been a consultant to the Swedish government on child maltreatment and on child safety.

    Carolina Jernbro is a PhD in Public Health at Karlstad University. Her research focuses on the prevalence, health effects, and disclosure of child maltreatment.

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