The In uence of Childhood Emotional Abuse On Adult Obesity

Hongwei Zhang Shanghai Jiao Tong University A liated Sixth People’s Hospital Ziqi Liu Shanghai Mental Health Center Hui Zheng Shanghai Mental Health Center Ting Xu Shanghai Jiaotong University A liated Sixth People's Hospital Lin Liu Shanghai Jiaotong University A liated Sixth People's Hospital Tao Xu Shanghai Jiaotong University A liated Sixth People's Hospital Ti-Fei Yuan Shanghai Mental Health Center Xiaodong Han (  18930172941@163.com ) Shanghai Jiao Tong University A liated Sixth People’s Hospital


Introduction
Early life adverse events, such as childhood trauma, results in a long-term effect on personal development and adulthood, such as alterations in psychiatric performance and metabolism states ( . At the same time, such a distressing psychological state also likely to increase indulgent food intake (Polivy, Herman, & McFarlane, 1994). Anxiety or dysphoric mood is associated with binge eating and emotional eating in overweight and has been considered a critical target to reduce excess body weight. (Cooper & Bowskill, 1986; Ostrovsky, Swencionis, Wylie-Rosett, & Isasi, 2013; Wilkinson, Rowe, Robinson, & Hardman, 2018). Depression is also related to appetite increment (Paykel, 1977). The prevalence of lifetime diagnosed anxiety and depression in obesity is signi cantly higher than in ordinary people (Zhao et al., 2009).
Based on the connection between childhood trauma, anxiety, and depression. Together with the high comorbidity of anxiety, depression, and obesity. Here, we aim to gure out (1) whether anxiety and depression could serve as intermediate factors between childhood maltreatment and obesity, and (2) whether anxiety and depression play equal main mediate effect in this relationship.

Participants
From September 2020 to January 2021, we retrospectively analyzed clinical data from 37 obese subjects and 37 demographic well-matched healthy people. All participants (1) aged above 18 years old; (2) could read and understand the description of each item of the questionnaire; (3) be voluntary participation in the survey and had signed the informed consent. The ethics committee had approved the study at Shanghai Sixth People's Hospital. All procedures followed the Childhood Trauma Questionnaire (CTQ) is designed for adolescents and adults to obtain a brief, reliable and valid assessment of traumatic experiences in childhood (Bernstein et al., 1994;Bernstein et al., 2003). It assesses the incidents of abuse and neglect in childhood, including physical abuse, emotional abuse, sexual abuse, emotional neglect, and physical neglect (Bernstein, Ahluvalia, Pogge, & Handelsman, 1997). CTQ has 28 items, and each item adopts a 5-point Likert score from 1 "never " to 5 "very often" according to the frequency of the experiences that occurred (Bernstein et al., 1994). A higher CTQ score indicates more severe childhood trauma. The total Cronbach's α of the Chinese version CTQ is . It had good reliability and validity (Kühner et al., 2007). The total Cronbach's α of the Chinese version BDI is 0.94 (Lu, 2011). BDI has 21 items, and each item consists of four self-evaluative statements scored 0 to 3, with an increasing score indicating greater depression severity.

Statistical Analysis
To test the common method biases, we performed Harman's single-factor test to exam this issue (Podsakoff, MacKenzie, Lee, & Podsakoff, 2003). Unrotated factors analysis revealed that the eigenvalues of 27 factors were >1. The rst factor explained only 26.42% of the variance, which was much lower than the threshold of 40%. The result indicated the absence of severe common method biases in the investigation.
Statistical analysis was carried out with SPSS 21. The comparison between obesity and healthy control was performed through the independent t-test (sex distribution comparison was veri ed through χ 2 -test). Then, the factors, which had a signi cant between-group difference, were selected to perform Pearson correlation analysis. The signi cance level alpha is 0.05 (two-tailed).
Multiple mediation analysis was conducted by the PROCESS macro in SPSS, developed by Hayes (Andrew F. Hayes, 2013). The multiple mediate models could estimate a speci c indirect effect is to describe how the independent variable leads the dependent variable through the intermediate factors (Andrew F Hayes, 2017). A bootstrap method was adopted to construct a 95% con dence interval for signi cance testing of mediating effects.

Results
The demographic information and clinical variables of the obese subjects and the healthy control group are exhibited in Table 1. There was no signi cant difference in gender distribution, age, and education years between the two groups.

Mediation effect testing
To ensure better external and ecological validity of this multiple mediation model, we performed the mediation effect testing with original data. With controlling of demographic information (age and education years), the PROCESS macro was used to verify the multiple mediating roles of anxiety, depression, and bulimia in the relationship between childhood emotional abuse and BMI. Table 3 presents the results of the mediation analysis, and Figure 2 shows the mediation pathway models.
We used the bootstrap method to test the signi cance of the mediating effects, in which the sampling process was repeated 1000 times to calculate the 95% con dence interval ( Table 4). The mediation pathway would be signi cant if the 95% con dence intervals of the various path coe cients do not contain 0. In both models, the total effect (Emotional abuse→BMI) was signi cant. For model 1, in which anxiety and bulimia as multiple medicate variables, the total indirect effects accounted for 56.33% of the total effects. Speci cally, the effect of the Emotional abuse→Anxiety→Bulimia→BMI pathway was signi cant (Effect size=0.082, 95% CI=0.018-0.283), accounting for 6.24% of the total effects. The effect of the Emotional abuse→Anxiety→BMI pathway was also signi cant (Effect size=0.473, 95% CI=0.0126-1.608), accounting for 36.03% of the total effects. But the effect of the Emotional abuse→Bulimia→BMI was not signi cant.
For model 2, in which depression and bulimia as multiple medicate variables, the total indirect effects accounted for 26.45% of the total effects. Speci cally, the effect of Emotional abuse→Depression→Bulimia→BMI pathway was signi cant (Effect size=0.140, 95%CI=0.003-0.423), accounting for 10.67% of the total effects. But the Emotional abuse→Depression→BMI pathway and Emotional abuse→Bulimia→BMI pathway were not signi cant.
When compare the multiple mediation result of these two models (Table 4), we found that (1) the indirect effects of model 1 (Effect size = 0.739, Percentage of total effects = 56.33%) was much higher than that of model 2 (Effect size = 0.347, Percentage of total effects = 26.45%).

Discussion
The present study illustrates the association between childhood emotional abuse and adult obesity, which is the rst time to describe the intermediate effect of anxiety and depression in such a relationship. The anxiety-bulimia pathway demonstrates that childhood emotional abuse would probably lead to obesity by aggravating anxiety and bulimic behavior.
The results showed that the obese subjects experienced more emotional abuse in childhood. Childhood emotional abuse is highly prevalent and easy to occur because passionate, verbal insults are instantaneous, less effort spent. In contrast, the consequence of emotional hurt is insidious and di cult to detect. Therefore, early life emotional abuse is central to understanding child maltreatment's latent effects (Viola et al., 2016). Furthermore, childhood emotional abuse would result in a series of di culties identifying emotions and emotional awareness (Goldsmith & Freyd, 2005), which would increase the susceptibility of developing anxiety and depression. Further, the anxious and depressive state would contribute to the incidence of abnormal eating behavior (Levinson et al., 2017). In this way, the obese subjects were more anxious and depressive than healthy people.
Previous studies reported that anxiety is strongly associated with binge eating and emotional eating (Ostrovsky et al., 2013). The obese subjects would eat more when they feel anxious, and the aroused effect would signi cantly reduce after a gluttonous eating (Slochower & Kaplan, 1980). Therefore, anxiety is a critical factor in childhood emotional abuse-obesity, since the high likelihood of an anxious emotional state triggers bulimic behavior. By contrast, the connection between depression and bulimia is ambiguous. A depressive state does not always increase eating. In a sample of depressed patients, only in 14% appetite was increased, while in 66%, appetite decreased, and in 20%, it showed no change (Paykel, 1977). Bradley M.Appelhans et al. reported that more severe depression is associated with more inferior diet quality (Appelhans et al., 2012). For these reasons, we believe that anxiety plays a vital role in leading these obese subjects to perform more bulimic behavior, which could release their anxious impulse but causing excessive fat accumulation.
To further prove the connection sequence of anxiety and bulimia, we built and examined another model in which bulimia is the rst multiple mediating variable and anxiety is the second multiple mediating variable. The model tting result is less satisfactory than the original model (anxiety was the rst multiple mediate variable; see supplementary: the regression coe cient of Emotional abuse→Bulimia→Anxiety/Depression→BMI was not signi cant). According to previous studies, anxiety disorders commonly had onset in childhood and frequently exists before eating disorders ( Obesity is di cult to prevent and treat since its etiology is complex and not completely understood (Wadden, Brownell, & Foster, 2002). Few studies have revealed the relationship between childhood emotional abuse and adult obesity or compare the mediating effect between anxiety and depression. Our study described one indirect pathway of childhood emotional abuse contributing to obesity and demonstrated that anxiety plays an important mediate role in this relationship. This result provides a new perspective to treat the obese subjects with early life adverse events. Except for bariatric surgery, psychological intervention also helpful in reducing the in uence of predisposing pathogenic factors. In future treatment, it would be bene cial to offer obese subjects with psychological therapy to reduce their anxiety and reduce bulimic behavior. Some limitations should be noticed. First of all, the sample size of the present study is relatively small. Future studies need to collect a larger sample to make a rmer conclusion. Second, the present study is a cross-sectional investigation.
Longitudinal designs and interventional experiments should be adopted in future studies to reveal the causality. Finally, the data collection based on the self-reported questionnaire, which inevitably concludes reported biases even though we had strictly controlled the response quality. More objective indicators of behavior tasks and evidence from neuroimaging are necessary.
In conclusion, obese subjects experienced more childhood emotional abuse, be more anxious, depressive, and bulimic than healthy people. Childhood emotional abuse may contribute to adulthood obesity, potentially mediated by anxiety and bulimia. In obesity treatment, psychological intervene would be helpful to reduce anxious emotion and then decrease bulimic behavior. 42. Zhao, G., Ford, E. S., Dhingra, S., Li, C., Strine, T.  Figure 1 Pair correlation diagram of emotional abuse, anxiety, bulimia, and BMI. BMI: Body Mass Index.