The prevalence of childhood and adolescent obesity is alarmingly high, with long-term health consequences. Multiple factors contribute to this, including biological, psychosocial, and cultural influences. Adverse childhood experiences (ACEs), encompassing various negative childhood events, are increasingly recognized as significant risk factors for various health problems, including obesity in adulthood. However, the association between ACEs and adiposity in children and adolescents is less well-understood, with inconsistent findings across studies. Prior research often focused on single time points, used BMI as the sole measure of adiposity, and lacked a thorough investigation of the role of childhood poverty as a potential modifier of the ACE-adiposity relationship. This study aimed to address these gaps by examining the association between ACEs (both cumulatively and individually) and adiposity trajectories (using both BMI and FMI) from age 5 to 17, considering the potential interaction with childhood poverty. The hypothesis was that higher ACE scores would be associated with steeper adiposity trajectories, with varying effects across individual ACEs, and a potential interaction with poverty.

Existing literature demonstrates a strong link between ACEs and adult obesity, with meta-analyses showing increased odds of obesity among adults reporting ACEs. However, research on the ACE-adiposity relationship in children and adolescents is less consistent. A meta-analysis estimated a modest association between child maltreatment and obesity, but findings varied across studies, sometimes showing associations only for specific ACEs, sexes, age groups, or adiposity measures. The need for multiple methods to verify ACE exposure and acknowledgement of sex differences were highlighted. Some studies showed significant associations only in girls or boys, with differing mechanisms. Most prior research used single time-point adiposity assessments and relied solely on BMI, potentially introducing measurement bias and neglecting the dynamic nature of adiposity development. Furthermore, the role of childhood poverty in this relationship remained largely unexplored, despite evidence suggesting an association between poverty, increased ACE risk, and worse health outcomes. The overlap between poverty and ACEs underscores the need to analyze these factors in conjunction.

This study utilized data from the UK Millennium Cohort Study (MCS), a nationally representative cohort of children born between September 2000 and August 2001, with follow-up sweeps at ages 3, 5, 7, 11, 14, and 17. Eight commonly studied ACEs were included, measured in early childhood (before age 3): parental separation, parental depression, parental drug use, parental alcohol misuse, interparental use of force, parental discord, harsh parenting, and physical punishment. A cumulative ACE score was created, categorizing participants into 0, 1, 2, and 3+ ACEs. Poverty was measured using the McClements below 60% median poverty indicator at ages 9 months and 3 years. Adiposity was assessed using BMI and FMI, calculated from height and weight (BMI) and body fat percentage (FMI) measurements at various ages. Covariates included offspring's sex, ethnicity, birth weight, maternal prenatal BMI, maternal age at birth, parental occupational social class, and parental highest qualification. Linear-mixed effect models were employed to analyze BMI and FMI trajectories, accounting for random slopes and intercepts, and incorporating a quadratic term for time. Complete-case analysis was used, including children with at least one adiposity measurement and complete data on ACEs, poverty, and covariates. Interactions between ACEs, poverty, and sex were tested. Analyses were conducted using STATA 17.

The study found a high prevalence of ACEs, with approximately three-quarters of children reporting at least one ACE by age 3. Analyses using the cumulative ACE score showed a less consistent relationship with adiposity than expected. There was no association between the ACE score and adiposity at baseline (ages 5/7), but a significant association was found for boys with 3+ ACEs, who had steeper increases in both BMI (β = 0.13, 95% CI: 0.02–0.24) and FMI (β = 0.09, 95% CI: 0.01–0.19) compared to boys with 0 ACEs. Analyzing individual ACEs revealed that parental depression was associated with steeper BMI/FMI increases in both sexes. Parental separation and physical punishment were associated with steeper increases in BMI/FMI only for girls. Interestingly, parental alcohol misuse was associated with a flatter increase in adiposity trajectories for both sexes. No interaction effect was found between ACEs and poverty on adiposity trajectories; however, children from impoverished households showed a steeper increase in BMI/FMI, particularly in models analyzing individual ACEs. Supplementary tables provide detailed breakdowns of these findings.

The findings reveal a complex relationship between early childhood ACEs and adiposity trajectories, highlighting the importance of considering both cumulative ACE scores and individual ACEs and acknowledging sex differences. The lack of association between cumulative ACE scores and adiposity, except in boys with high ACE counts, could be attributed to a latent period before the effects of ACEs manifest biologically. Sex differences may be explained by sociocultural factors, such as differences in girls' and boys' propensity to seek social support, which might mitigate the negative impact of ACEs. Biological pathways related to stress system hyperactivation and puberty onset could also contribute to these differences. The differing associations between individual ACEs and adiposity suggest that the cumulative score approach may mask or dilute the unique effects of individual adversities. The lack of interaction between poverty and ACEs suggests that poverty increases the risk of ACEs but does not modify their impact on adiposity. Poverty itself, however, was associated with steeper adiposity trajectories.

This study provides evidence for associations between ACEs and adiposity trajectories in children and adolescents. Cumulative ACE scores were associated with steeper increases in BMI and FMI among boys with 3+ ACEs, while individual ACEs such as parental depression showed consistent effects across sexes, and parental separation and physical punishment showed stronger associations in girls. No interaction between ACEs and poverty was found. Future research should explore the underlying mechanisms driving these complex relationships and further investigate the different impacts of various ACEs across sexes.

The study acknowledges several limitations. The use of both cumulative ACE scores and individual ACEs each has inherent strengths and weaknesses; for example, the cumulative score assumes equal weighting of all ACEs, which may not accurately reflect their individual contributions to adiposity. Measurement biases related to specific ACEs (e.g., parental alcohol misuse) and the reliance on parental reporting could lead to underestimation or misclassification. The complete-case analysis may have introduced attrition bias. Finally, the study establishes associations but cannot infer causality.