Lifestyle behavioural risk factors and emotional functioning among schoolchildren: The Healthy Growth Study

Abstract

Background

There is an increasing focus on lifestyle as a factor in the pathogenesis of mental health disorders; however, this has been relatively underexplored in child populations. This study aimed to assess the relationships between behavioural lifestyle factors and emotional functioning in a large, population-representative sample of schoolchildren in Greece.

Methods

A representative sample of 2,240 schoolchildren, aged 9–13 years, participated in the Healthy Growth Study during 2007–2010. Emotional functioning was measured using the Dartmouth COOP Functional Health Assessment charts/World Organization of Family Doctors Charts. A score of 3 or higher out of 5 indicated poorer emotional functioning. Participants self-reported dietary intake via three 24-h dietary recalls; fruit, vegetable and soft drink consumption were the dietary variables of interest. Participants’ self-reported daily time spent in moderate to vigorous physical activity, and watching TV or playing video games were used to assess physical activity and sedentary behaviour.

Results

In fully adjusted models, females were at a greater risk of experiencing impaired emotional functioning compared to males (OR 1.76, 95%CI 1.44, 2.15, p < 0.01). Overweight/obesity compared to normal body weight (OR 1.52, 95%CI 1.31, 1.77, p < 0.01) was associated with poorer emotional functioning. Three hours or more of daily average physical activity compared to less than one hour (OR 0.59, 95%CI 0.40, 0.86, p < 0.01) was associated with improved emotional functioning. Consuming soft drinks compared to non-consumption (OR 1.24, 95%CI 1.02, 1.51) was associated with poorer emotional functioning; this became non-significant after corrections for multiple comparisons were made. Clustering of municipalities was accounted for in all models.

Conclusions

Whilst findings were cross-sectional and causality cannot be inferred, this study highlights the interdependence of emotional and physical functioning in schoolchildren. This points to the potential for targeting shared risk factors for both physical chronic diseases and emotional and mental health conditions among children. Further longitudinal evidence will identify the potential for such shared intervention targets. Adopting a comprehensive, integrated approach to children’s emotional, mental, and physical health is warranted.

Introduction

Common mental disorders, such as anxiety and depression, are highly prevalent globally. On-going research is seeking to understand the risk factors and causal pathways during childhood and adolescence that increase the risk of current and future mental health problems [1]. Consistent population-level evidence supports the role of lifestyle behaviours in the development and maintenance of mental health problems, although this evidence has primarily been conducted among adolescents and adults. Understanding the relationship between dietary and physical activity behaviours and mental and emotional health during early years holds great public health potential on a global scale [2]. With international efforts to determine how to curb growing childhood obesity rates, and the large chronic disease burden attributed to lifestyle factors established in early life, there is a good potential for health benefits of healthful nutrition and physical activity regarding both physical and mental health outcomes [2].

Recent meta-analyses confirm diet quality as a determinant of depression risk in adults [3] and another recent meta-analysis of randomized controlled trials has shown that dietary interventions significantly reduce symptoms of depression across the general population [4]. The more limited evidence regarding dietary habits, nutritional status and mental health among children to date has been summarised in systematic reviews [5,6]. Overall, the cross-sectional evidence suggests unhealthy dietary patterns (characterised as ‘junk foods’, Western-diets, ‘extras’ foods) is significantly associated to poorer mental health (including depression, low mood and anxiety) among children. Longitudinally, there is a consistent relationship between healthful diets (increased fruits and vegetables, unprocessed, nutrient-dense foods) and improved mental health status as well as some evidence for poorer dietary quality and poorer mental health outcomes [5,6]. There are significant limitations to the available evidence in younger age-groups, including the failure to account for socio-economic circumstances (known to impact upon mental health outcomes and food-related behaviours) and other lifestyle behaviours. Critically, most of the available evidence has emerged from USA, United Kingdom, Australia and Canada, and focused on adolescence as opposed to child populations [7]. There is a need to examine such relationships in culturally diverse and younger-aged populations.

The relationship between physical activity and mental health in young people is well established [[8], [9], [10]], and likely driven by multiple factors including the neurobiological responses to exercise [11], the social and relationship-building opportunities afforded by physical activity, and an increase in the sense of achievement and self-esteem [[8], [9], [10]]. Indeed, meta-analyses of randomized controlled trials have convincingly demonstrated that increasing physical activity can provide effective treatment for young people with clinical depression [12]. It has been discussed that while physical activity may enhance psychological well-being, increased engagement in sedentary behaviours associated with modern society may also negatively impact on well-being, independently of exercise itself. For instance, screen use among young people has previously been shown to significantly relate to lower scores of self-esteem, reduced pro-social behaviours, and lower academic achievement [8,13].

We sought to strengthen the epidemiological evidence for the relationships between diet- and physical activity-related behaviours, and chronic mental and physical disease, and investigate these relationships for the first time among school-aged children population based in Greece. Population-level evidence is needed to inform prevention strategies to reduce the burden associated with lifestyle driven conditions and mental and physical illness at the national and international level, and this will be the first study to examine such relationships in the Greek schoolchildren population. Specifically, this study aims to identify the relationship between health behaviours such as the consumption of fruits, vegetables and soft drinks, time spent in moderate to vigorous physical activity and daily time spent using screens, as well as overweight/obesity, and the emotional functioning of schoolchildren in Greece.