To our knowledge, this is the first study to assess the association between children’s mental health status after liver transplantation and its associated factors in the context of their daily lives. The findings indicate that children who received transplants were more likely to have mental health problems. Additionally, parental mental health problems, less time spent doing physical activities, and inadequate parent-child interactions were associated with higher mental health risks for children post-surgery. The findings highlight that the mental health of children who have undergone transplantation surgery should be a focal point of research. Furthermore, this study reveals the importance of parental mental health, parent-child interactions, and physical activity in promoting mental health among children who have undergone transplantation surgery. This information is pertinent to developing health programs aimed at parents of pediatric transplant patients.

Our results have provided a valid theoretical basis for improving the mental health of children after liver transplantation. With the development of pediatric liver transplantation, the focus has shifted from patient survival to a healthier QOL. Mental health problems affect these children’s daily social lives and may also impact graft survival-rates across organ transplant groups.

Our results indicated that the prevalence of emotional and behavioral problems was significantly higher for children in the post-surgery group than in the control group. A multicenter study in North America [19] showed significantly lower Health Related Quality of Life (HRQOL) scores in children with liver transplants compared with healthy children, especially in the categories of school performance and emotional functioning. A single center follow-up in Chile [20] showed that patients under the age of four years consistently indicated good HRQOL scores. This may be because parents answered the questionnaire. Contrarily, most school-age patients reported poor HRQOL in all aspects, likely because of their irregular attendance of school activities. Another study in Germany [21] demonstrated that there was notable family strain surrounding the pediatric liver transplant recipients, when compared with a normative sample of chronically ill children, or children with disabilities. Significant associations have been observed between family strain in parents and psychosocial dysfunction in children post-surgery. These findings partly support our hypotheses, and our study confirms and extends existing research in this area. Children in the post-surgery group were more susceptible to developing psychological problems than those in the control group. Thus, maintenance of good mental health supports children’s well-being, which is an essential goal for care before, during, and post liver transplantation.

Our results indicated that engaging in physical activity, quality of parent-child interactions, and parental mental health were factors associated with the mental health of pediatric liver transplantation patients. Furthermore, a lack of physical activity, inadequate parent-child interactions, and parental mental problems can serve as independent risk factors for declining mental health in pediatric liver transplantation patients.

Our results also showed that medium-intensity physical activity was associated with decreased mental health burden for pediatric transplant patients. Physical activity may improve mental health by facilitating the release of endorphins and the increase of brain-derived neurotropic factor and the growth of new capillaries, enhancing the structural and functional compositions of the brain [22]. Children with chronic illnesses are prone to having lower levels of social competence, which may negatively impact peer relationships, which is a predominant influential factor on self-esteem and general well-being [23, 24]. Physical activity improves self-concept and mental health in young people through several psychosocial paths [25]. Physical activity can also improve mental health through a range of potential behavioral mechanisms including sleep duration, sleep efficiency, sleep onset latency, and reduced sleepiness [26].

An exercise duration of ≥ 60 min was proven to significantly improve overall mental health, compared to those peers who engaged in an exercise program of < 60 min [27]. In a large U.S. sample, physical activity was reported to improve mental health burden, and an exercise duration of 45 min per day, 3‒5 times per week, was identified as the most important factor [28]. However, increased duration and intensity of exercise were not necessarily better for children. In this study, we found that children who engaged in vigorous physical activity for 30 min or more per day did not have improved mental states. This may be related to the physical health of pediatric transplant patients, and/or the results of excessive attention from caregivers.

Consistent with the literature on physically healthy children, our findings demonstrated that positive parent-child interactions improved the mental health of children who had undergone transplant surgery. A positive, nurturing environment, especially with high-quality parent-child interactions, plays a vital role in early childhood development, including cognitive and psychosocial development [29, 30]. Previous evidence suggests that high frequencies of positive parent-child interactions have positive effects on children’s psychosocial functioning [31]. Additionally, positive caregiver-child interactions can buffer the adverse effects of maltreatment on social difficulties [32].

The current research shows that up to one-third of parents of children suffering from a life-threatening illness have some symptoms of general stress disorder, such as avoidance behaviors, impulsive thoughts, or irritability [33]. However, little is known about the impact of the transplant experience and the ongoing health issues on children’s families, especially their parents. Evidently, parents play an essential role in their child(ren)’s development and they must assume a tremendous amount of responsibility [21]. This study demonstrated strong inter-relations between family strain and emotional and behavioral disturbances in children who received liver transplants. The most important factor affecting children’s ability to cope with treatment is the response of their parents to the disease and treatment [34]. Reciprocity can be assumed in that if the parents are heavily burdened and/or anxious, it may cause psychosocial dysfunctional traits to manifest in the child. Hence, if parents can cope effectively with the burden of care, the child will effectively adapt to the conditions of their illness.

This study addresses the existing research gap regarding the mental health of young children after liver transplantation. Further, it makes a significant and novel contribution in identifying that a lack of physical activity (< 30 min/day), poor quality of parent-child interactions, and parental mental health problems are risk factors for emotional and behavioral disorders in pediatric transplant patients. The results of this study indicate that further studies aimed at the developing evidence-based parenting interventions may be helpful in improving the long-term QOL of transplant patients. Additionally, this was a large sample retrospective research study, using high quality control group data by the PSM method that increased between-group comparability.

The limitations of this study also need to be considered. First, although large-sample data were used in this study, it was not obtained by a strict stratified sampling method. This limits the generalizability of the research. Second, this is a retrospective study which only provides evidence of the correlations between mental health of pediatric transplant patients and associated risk factors, and thus well-designed randomized controlled trials are needed to elucidate the causal relationship. Finally, the subjective measures used in the current study might be inevitably influenced by recalling bias.