Childhood maltreatment (CM) is a serious problem for children’s future development. The incidence of childhood maltreatment (CM) among college students in China was 64.7 percent, with the highest prevalence observed for emotional neglect (60.0%) and the lowest for sexual abuse (15.7%)^[1]. A growing body of evidence suggests that CM related to multiple physical and mental health outcomes, such as depression and anxiety, especially in obesity ^[2].

Obesity among adults is one of the major health concerns. WHO estimates that more than 1.3 billion adults worldwide are overweight, and a further 600 million are obese^[3]. Body mass index (BMI) measures general obesity (ie, abnormal or excessive fat accumulation), abdominal obesity is fat accumulation under the skin of the abdomen or in the internal organs of the abdomen ^[4]. Measures of abdominal obesity are better predictors of cardiovascular disease and all-cause mortality than is general obesity^[4].

Although numerous previous studies have established a positive correlation between CM and adult obesity, several key questions remain that warrant further exploration. First, whether the effects of the five types of childhood abuse on obesity in adulthood uniform or heterogeneous? Evidence suggests that all five types of CM are positively associated with BMI in adulthood, but others believed there was no significant association between physical neglect or abuse, sexual abuse and adult obesity (BMI), among the various types of child abuse^[5]. Second, whether the associations between subtypes of child maltreatment and obesity indexes differ across sexes? Previous studies have shown that childhood physical abuse in girls was not associated with obesity in adulthood, but recent studies have shown the specificity of physical and sexual abuse appeared to be stronger among females^[6]. In addition, the social context and cultural background of China differ from those of Western countries, which might impact the relationship between CM and obesity. For example, unlike in Western countries, Chinese parents prefer physically punitive education, which increases the risk of childhood somatic abuse and may affect obesity indicators in adulthood. Third, is there an interaction effect between recent adverse life events and CM on obesity indexes? Previous research indicates a connection between childhood maltreatment and obesity, suggesting that more recent adversities may exert a different influence on health than remote ones, including factors like depressive symptoms, anxiety, and pain^[5]. Stressful events occurring in the past six months had a more pronounced impact on neuroticism levels compared to distant events, with neuroticism levels serving as crucial predictors of both mental and physical health issues. There was a close link between early and recent adversity experiences, showing an interaction at the level of recent adverse events which heightened the risk of mental health problems. Nonetheless, limited research has delved into the repercussions of recent adverse life events on obesity.

In summary, exposure to CM might be associated with obesity in early adulthood. There is a variation in the prevalence of obesity and childhood abuse across different countries, and the relationship between types of CM and obesity indicators has not been validated among individuals in early adulthood in China. To address this gap, our study employed a linear regression model to explore the associations among CM, obesity, and recent adverse life events.

We recruited college students via flyers and posters between October and November 2023. There were 337 college students from Anhui Medical University (Hefei, Anhui, China) in this study. All enumerators were uniformly trained before the survey. We provided a self-administered questionnaire on adolescent mental health behaviors, which collected information regarding general demographic characteristics (Supplementary Table S1, available in www.besjournal.com). The study protocol was approved by the ethics committee of Anhui Medical University (No. 20210355), and informed consent was obtained from all participants. Moreover, the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) was used to report observational data (Supplementary Table S2, available in www.besjournal.com).

The inclusion criterion was as follows: freshmen of the School of Public Health, Anhui Medical University, China (aged ≥ 18 years). Exclusion criteria included severe liver/kidney disease, physical disability, serious injury or infection, use of psychotropic drugs, and incomplete questionnaire data. Individuals with incomplete information on CM (n = 12) and those with missing body composition measurements (n = 20) were excluded from this study. Finally, 305 participants (aged ≥ 18 years) were included in this study (Supplementary Figure S1, available in www.besjournal.com).

Figure S1.  The study follow chart.

The Chinese version of the Childhood Trauma Questionnaire-Short Form (CTQ-SF) was used to assess CM^[7]. The CTQ-SF evaluates five dimensions, encompassing emotional abuse, physical abuse, sexual abuse, emotional neglect and physical neglect. Participants rated their responses to each question on a 5-point Likert scale, yielding total scores on the five dimensions ranging from 25 to 125. Higher scores indicate that participants have experienced severe child maltreatment (Cronbach α = 0.86).

Two research assistants guided participants through the questionnaire. Height and weight were measured using appropriate devices, with participants asked to remove their shoes before measurement. Height readings were expressed in centimeters and weight in kilograms. The result is averaged twice. Waist circumference (WC) was measured by the researchers at the fullest part of the buttocks. Participants were instructed to stand upright with legs together and arms naturally hanging down, and a tape measure was placed horizontally from the pubic symphysis to the most convex point of the gluteus maximus muscle.

Trained researchers carefully measured participants’ body composition using the InBody S10 (InBody Corp., Seoul, Korea), a medical grade body composition analyzer, that utilizes advanced technology, including an 8-point tactile electrode system, direct segmented measurement, and multifrequency analysis. Data on abdominal obesity indexes, including fat mass (FM), body fat percentage (PBF), WC, abdominal visceral fat area (VFA), waist-hip ratio (WHR), and general obesity index such as body mass index (BMI) were recorded by the monitor, which is seamlessly integrated with telemedicine software for efficient storage in each participant’s electronic health record.

The Chinese version of the Adolescent Self-Rating Life Events Checklist (ASLEC) comprises 27 negative life events specifically tailored to evaluate recent mental experiences in adolescents^[8]. The ASLEC scale encompasses 6 factors, including interpersonal relationships, academic pressure, punishment, loss, health adaptation, and other factors. Each item is rated on a six-point Likert scale, ranging from 0 to 5. By summing up all experienced events, the total number of negative life events encountered by the respondent can be calculated, with a higher total score indicating elevated stress levels (Cronbach α = 0.93).

Drawing from prior research^[9], we incorporated the following covariates into our analysis: age, gender (male, female), family type (nuclear family, single-parent family or extended family), family economic status (< 5,000 yuan, 5,000–10,000 yuan, or > 10,000 yuan), parental educational attainment (primary school and below, junior high school, or senior high school), smoking habits (≥ 1 smoking episodes in the last 30 days, yes or no), and drinking habits (≥1 incidents of alcohol consumption in the last 30 days, yes or no).

The data is depicted as mean ± SD or median (interquartile range). For discrete variables, absolute frequency, percentage, and 95% confidence intervals were computed. Variances in different parameters between two groups were assessed using the unpaired t-test, while the Fisher exact test was employed to compare frequencies between the two groups. To test for a potential association between CM and adiposity indicators, linear regression models were used to obtain β coefficients and 95% CIs for changes in adiposity indicators. Sex-stratified linear regression analyses were conducted to assess the correlation between CM and indicators of obesity in early adulthood after adjusting for covariates. To assess the effect of recent adverse life events on this relationship, linear regression analyses were performed to assess the correlation between CM, recent adverse life events, and indicators of obesity in adulthood after adjusting for covariates and to calculate the β-value. All analyses were performed with SPSS (version 27.0; IBM Corp). A two-sided P value of ≤ 0.05 was considered statistically significant.

This study assessed the association between five dimensions of CM and obesity indicators through multiple comparisons. To reduce the risk of a type I error, a 99% CI was used for the effect size of each dimension analyzed. After adjusting for covariates, emotional abuse demonstrated a stronger association with obesity indicators (VFA, BMI, PBF, FM, WC, and hipline). Physical abuse and emotional neglect were associated with two obesity indicators each (physical abuse: FM and hipline; emotional neglect: BMI and hipline). Sexual abuse showed an association only with hipline, however, no significant associations were found between somatic neglect and obesity indicators. Table 1 provides further details. It is well established that individuals who have experienced CM often adopt unhealthy lifestyle behaviors, such as detrimental exercise patterns and poor dietary habits, which can substantially contribute to obesity.

In addition, we performed sex-stratified linear regression models to explore the relationships between different types of CM and obesity indicators. The results indicated that none of the five types of CM were associated with obesity indicators in females. However, in males, emotional abuse showed a stronger association with obesity indicators (VFA, BMI, PBF, FM, WC, and hipline). Moreover, both physical abuse and emotional neglect exhibited significant associations (see Figure 1, Supplementary Figure S2, Supplementary Table S3, and Supplementary Table S4, available in www.besjournal.com). One plausible explanation for these findings is that males are more prone to experiencing the adverse effects of childhood abuse. Furthermore, in China, higher education is associated with an increased risk of overall obesity and abdominal obesity in males, whereas this risk is lower among females. Therefore, maltreated male college students may experience more psychological and behavioral problems, such as poor sleep and reduced physical activity, which contribute to obesity in early adulthood. However, a recent study in Germany reported contrasting findings^[6]. This difference may be explained by the fact that the German study focused on a middle-aged population, whereas our study focused on university students in China. The impact of CM on the onset of obesity in adolescents may manifest over 2-5 years^[10], or possibly even longer. Given that this study was conducted within the Chinese cultural context, the cultural and social context unique to China may influence the extrapolation of the results to other countries.

Figure 1.  Relationship between child maltreatment and obesity indicators by sex; abbreviations: EA, Emotional abuse; PA, Physical abuse; SA, Sexual abuse; EN, Emotional neglect; PN, Physical neglect; Models were adjusted for age, sex, drink, smoke, father education, mother education, family type, family economic and recent adolescent self-rating life events. (A two-sided P value of ≤ 0.01 was considered statistically significant).

The results further indicated that recent adverse life events were significantly associated with hipline (β=–0.079; 99% CI: –0.153 to –0.006) and WHR (β=0.001; 99% CI: 0.000 to 0.001). In addition, we explored whether there was an interaction between recent adversarial life events and childhood abuse on obesity metrics. The results of the multiplicative interaction effects showed that physical abuse and neglect, sexual abuse, and emotional neglect interacted with recent adverse life events on the hip circumference. However, the results regarding joint effects did not show statistical significance. They revealed that participants who experienced childhood abuse and also recently encountered moderate levels of adverse life events tended to exhibit lower levels of BMI. One plausible explanation is that children who experienced childhood abuse may be more susceptible to adversities in adulthood. Furthermore, persistent stress may affect the brain’s response to food, thus predisposing individuals to poor eating habits, which, if prolonged, could increase the risk of obesity. Therefore, it is crucial to address the impact of recent adverse life events on abdominal obesity in early adulthood. Further details can be found in Table 2, Supplementary Table S5, and Supplementary Table S6, available in www.besjournal.com.

Childhood maltreatment affects obesity indicators in adulthood, the effects of this adverse experience are long-lasting, and intervention strategies to prevent obesity should consider addressing adverse forms of maltreatment in childhood. In addition, it is recommended that relevant authorities conduct routine screening for CM in order to reduce the risk of CM on obesity.

This study has several limitations. First, data on early childhood maltreatment were gathered through a retrospective self-report questionnaire, potentially introducing recall bias. Second, the participants were exclusively recruited from a single college in China, restricting the broader applicability of our results to young adults from varied demographic backgrounds. Third, the indicators of obesity in this study were somewhat limited, and future studies could include objectively measured indicators that more accurately reflect obesity. Fourth, this study did not consider the influence of several potential confounders (such as physical activity and dietary patterns) on the outcomes. Fifth, the obesity detection rate in this study was low and the sample size was small, which could impact the reliability of the findings. Therefore, our results remain preliminary, and future studies in China should aim to include a larger sample size to further validate our findings.

In summary, four subtypes of CM (except for physical neglect) are associated with obesity indicators in early adulthood, especially in emotional abuse. The associations between exposure to CM and obesity-related traits in early adulthood are predominantly observed in males. Furthermore, recent adverse life events were significantly associated with obesity. Overall, this study highlights the importance of addressing both distant (CM) and recent adverse life events to alleviate obesity in early adulthood.