The association of the executive functions with overweight and obesity indicators in children and adolescents: A literature review

Highlights

• Systematic review supports the relationship between executive dysfunction and excessive body mass in children and adolescents.

• The strongest evidence supports the relationship between poor inhibitory control and higher BMI, being overweight or obese.

• There is a need to systematize the way of defining EF in the context of studying their relationship with body mass.

Abstract

The prevalence of obesity in children and adolescents has become an increasing health problem all over the world. Prior studies suggest there is a relationship between excess body mass in adults and executive functions (EF). The paper analyzes recent studies on the association of obesity indicators and EF performance in children and adolescents. We analyzed four types of studies: comparison studies with obese and healthy children, cross-sectional studies describing dependencies between EF and BMI, follow up studies applying EF as a predictor of overweight/obesity and studies describing the effect of weight reduction on improving EF. We interpreted the results based on the categorization of EF into three main processes: inhibitory control, working memory, cognitive flexibility, and higher-level EF such as reasoning, problem-solving and planning. The strongest evidence supports the relationship between poor inhibitory control and higher BMI, overweight or obesity. However, the mechanism of the association is still unclear. A better understanding of the EF-obesity link may be relevant for the prevention of obesity or help in EF deficits improvement.

Introduction

Obesity is currently considered one of the most serious growing health problems around the world. According to World Health Organization (WHO) reports, in 2016 over 340 million children aged 5–19 years were of excess weight (WHO, 2018). In Europe, the rate of children aged 6–9 with overweight and obesity was 22.7%–53.05% depending on the country (Wijnhoven et al., 2014). Although statistical analysis suggests that in recent years the upward trend in obesity has slowed, the number of obese children is still alarming (Kelsey et al., 2014), especially since childhood obesity increases the likelihood of being obese in adulthood (Luppino et al., 2010). Furthermore, being obese affects physical health (Sahoo et al., 2015), as well as causes psycho-social consequences during childhood (Sahoo et al., 2015; Luppino et al., 2010).

Obesity is a disease of multifactorial background, hence it is examined extensively in many aspects: biological (e.g.: genetics) (Locke et al., 2015; Frayling et al., 2007), socioeconomic (Petraviciene et al., 2018; Wagner et al., 2018; Gibbs and Forste, 2013) or psychological (Miller et al., 2018; Stoeckel et al., 2017; Beck, 2016; Tanofsky-Kraff et al., 2006). However, recently the attention of many researches has been focused on the relationship between obesity and executive functions. Executive functions (EF), also called executive control (Berthelsen et al., 2017), are neurocognitive mental processes involved in goal-directed behavior, planning and monitoring, such us: inhibitory control, shifting, delaying of gratification, selective attention, sustained attention, working memory (Berthelsen et al., 2017). According to neuroimaging studies, executive functions are processes occurring at the prefrontal and parietal regions of the brain (Chung et al., 2014). Across the lifespan, EF develop intensively during childhood into adolescence and decrease during aging (Zelazo et al., 2004). The proper functioning of EF is relevant for physical health, as well as mental health, school achievements and job success (Diamond, 2013). It is thought that the following factors have an influence on EF development: socioeconomic status, preterm birth, physical activity, sleep deprivation, stress, social network or genetic background (Zysset et al., 2018).

Understanding the mechanisms of obesity is important for further prevention from early childhood. Therefore, it is important to synthesize the results of previous research on the relationship between EF and obesity, as it could be useful in early psychosocial intervention and in the health education area. According to our knowledge, several systematic reviews of the EF-obesity relationship in adults (Rotge et al., 2017; Veronese et al., 2017; Prickett et al., 2015; Fitzpatrick et al., 2013) or across the lifespan (Yang et al., 2018; Gettens and Gorin, 2017; Smith et al., 2011) have been published, however, only a limited number of studies address this association exclusively in children and adolescents. The aim of this study was to assess the relation between EF and obesity in children and youths based on a systematic review of the relevant research. In contrast to previous reviews we paid attention to various obesity indicators, not only the most popular BMI, but also body fat, visceral fat and waist circumference. Furthermore, we applied a different division of executive functions than in the previous works. Since various names of EF and a variety of diagnostic tools are in use the applied division was relevant for explicit interpretation of the research results.