The impacts of multiple obesity-related interventions on quality of life in children and adolescents: a randomized controlled trial

Rates of obesity are rapidly increasing throughout the world, posing a serious public health concern. Globally, the prevalence of obesity is highest in developed countries, while two-thirds of obese individuals hail from developing countries. Between 1975 and 2016, the percentage of obese adults increased almost threefold [1]. Moreover, the average weight of children had risen over 5 kg within the last 30 years in the United States, with even more rapid increases in low- and middle-income countries between 2002 and 2018 [2‐4]. In China, approximately 43% of adults and 20% of children are overweight or obese owing to changes in traditional lifestyle such as the increased popularity of Western fast food, declines in the regular practice of physical activity, and increased prevalence of a sedentary lifestyle [5]. It is therefore important that more efforts be made to combat this obesity problem.

Being overweight or obese is extremely harmful and can affect both physical and psychological health, increasing the risk of chronic non-communicable diseases including type 2 diabetes, hypertension, and fatty liver disease [6, 7]. In recent years, a strong link between obesity and various cancers has also been identified [8]. Obesity is thought to contribute to approximately 16–20% of cancer-related deaths in women and 14% in men [9]. From a psychological perspective, being overweight or obese increases the susceptibility of children to depression, anxiety, emotional disorders, and mood disorders [10, 11]. Horae et al. [12] found that children who are overweight or obese are 1.83 times more likely to suffer from depression than their normal-weight counterparts. Similarly, Sanderson et al. [13] found that children who were overweight or obese were more likely to suffer from mood disorders over the course of a 20-year longitudinal cohort study. In contrast, maintaining a normal body mass index (BMI≦25 kg/m²) is a protective factor with the potential to prevent up to 90,000 cancer deaths per year in the United States alone [14]. It is thus very clear that being overweight or obese can adversely affect quality of life (QoL) in children.

The exact genetic and environmental factors that influence obesity are complex [15]. Genes are thought to be major contributors to the development of these metabolic conditions, while environmental factors such as diet and exercise are generally regarded as being substantially easier to change in order to prevent excess weight gain [16, 17]. Lifestyle modifications including dietary changes and physical activities remain the foundation for optimal prevention and treatment strategies in overweight and obese children in existing studies [18, 19]. In combination with exercise, diet can further improve levels of high-density lipoprotein (HDL) cholesterol, fasting glucose, fasting insulin, and psychological health [7, 20]. Despite these clear advantages, most individuals have substantial difficulties maintaining dietary- and exercise-based interventions over extended time periods [17]. In general, after acute intervention efforts end, most subjects revert to their original lifestyle. Therefore, it is important that a health education approach be employed so as to improve the positive attitudes and behaviors of these individuals.

In summary, being overweight or obese can adversely impact the QoL of children and adolescents, and obesity-related interventions can improve QoL in obese children. However, children often have difficulty maintaining the behaviors introduced during these intervention efforts. Therefore, the aim of present study was to evaluate the impact of a comprehensive family-individual-school-based intervention approach involving obesity-related health education, diet control, and physical exercise on the QoL of Chinese children and adolescents.

QoL is defined by the WHO as an individual’s perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards, and concerns [25]. The QoL index is multidimensional and artificial construct [26], and refers not only to the absence of disease or infirmity but also to a state of complete physical, mental, and social well-being [27]. Previous studies on QoL have mainly focused on its physical, psychological, and social dimensions [28]. However, as participants in our study were in adolescence, the impact of pubertal development on their QoL [29] was also assessed by incorporating a pubertal dimension into our assessment tool that assessed puberty-related feelings and pubertal cognition. This dimension, along with the standard physical, social, and psychological dimensions, was used to explore the efficacy of family-individual-school-based interventions on QoL in school-aged children and adolescents.

In our study, we found that the psychological, social, and pubertal dimensions as well as overall QoL were all significantly improved following the implementation of our family-individual-school-based intervention strategy. QoL was also increased at final follow-up in the control group, although the improvement in the intervention group was greater. Our results revealed that the improvements in psychological QoL were greatest in the intervention group, increasing by 2.77 following intervention. Increases in the pubertal dimension were less profound, while overall QoL was substantially improved by 6.86 points following intervention.

We observed superior enhancement in the psychological QoL of students in the intervention group, consistent with the work of Kovacs E et al. [30], although inconsistent with the work of Warkentin LM et al. [31], who found that physical activity did not significantly improve psychological QoL. At present in China, many thin children, and particularly girls, often report feeling somewhat fat [32], indicating a lack of body image confidence in these children. As our intervention included obesity-related health education, it encouraged participants to accept their own appearance and body image in a positive light, which may account for some of the observed improvements in the psychological QoL dimension scores. There is increasing evidence indicating that physical activity is positively associated with self-esteem and self-efficacy [33, 34], and these favorable traits can improve confidence and life satisfaction, thus contributing to higher QoL. With respect to the pubertal dimension of our QoL scale, the positive changes observed in the intervention group were also greater than those in the control group. No previous studies have focused on this dimension, and so we are unable to compare these results with those of other studies. All participants in this study were adolescents, and as such were undergoing major physical and psychological changes, with psychological maturation often occurring later than physical maturation during this key period. Being overweight or obese will often result in the earlier onset of puberty, widening this gap further [35]. For instance, girls with more body fat content are more likely to experience menarche at younger ages [36]. As our comprehensive obesity-related strategy can reduce fat mass in children and adolescents, it can narrow this gap and thereby improve pubertal QoL.

However, our research identified no intervention-related impact on the physical QoL dimension relative to the control group, which was inconsistent with previous results suggesting that physical exercise can improve QoL [31, 37, 38]. This inconsistency is likely a result of the particular study populations used in each study, as a previous literature review found the influence of weight status on QoL was greater in clinical populations than in normal populations [28]. Our participants were all children in grades 4–5 and 7–9, and all had good physical QoL, so there was little room for improvement of this dimension, whereas in previous studies regarding the effect of obesity-related interventions on QoL [6, 7, 11], participants were largely obese or overweight individuals that had a lower and less stable physical QoL. Therefore, it is more difficult to improve physical QoL for normal participants than for those individuals with physical health issues. We also found that our intervention measures did not affect social QoL, unlike the results of a previous study by Uritani D et al. [39]. This difference may be a consequence of the fact that children and adolescents become more self-centered and rebellious during adolescence but lack sufficient competence to deal with it, leading to more conflicts between parents and adolescents, conflicts between peers, and conflicts between teachers and students. Therefore, in future studies, it will be important to further examine adolescent mental health.

Our study results suggested that the efficacy of this intervention strategy varied between boys and girls, with a much clearer effect in boys, which is inconsistent with the results of previous studies [40, 41]. Brown DW et al. [42] have previously found that physical activity improved quality of life for both men and women. The sex difference observed in our study may be due to the fact that the effect of physical exercise on overall QoL is better than that of diet control [43]. Boys prefer physical exercise and were more likely to adhere to the intervention measures in the present study, and Yiyi Ouyang et al. found that males were more likely to have greater self-efficacy and self-affirmation relative to females, potentially further explaining this sex difference [44]. In addition, there are some prior studies indicating that boys suffer greater QoL impairment than do girls when obese or overweight [45], making it easier to improve the QoL of boys relative to that of girls. However, these results still raise questions regarding pre-adolescent emotional development, puberty issues, and self-image from a gender perspective and make it uncertain as to whether this approach can be generalized to other populations. Therefore, these disparities between boys and girls require further in-depth research.

Family-individual-school-based interventions incorporating obesity-related health education, physical exercise, and diet control can improve psychological and pubertal well-being, as well as overall QoL in children, particularly among boys.