Obesity and stress share a complex, bidirectional relationship throughout life. This interplay involves various factors like genetics, lifestyle, medication, and mental distress, and is further complicated by the activation of glucocorticoids. Obesity increases stress risk due to comorbidities limiting daily activities and weight stigma. Adverse Childhood Experiences (ACEs), encompassing various negative events during childhood, impact both obesity and stress, potentially influencing stress levels in individuals with obesity. This study aimed to evaluate the associations between obesity, ACEs, and stress during the COVID-19 pandemic, examining if ACEs modified the obesity-stress link.

Existing literature highlights the intricate connection between obesity and stress, with bidirectional influences throughout the lifespan. Studies reveal mechanistic pathways linking stress and obesity, including health behaviors, glucocorticoid activation, and mental health issues. Obesity's impact on stress is attributed to comorbidities restricting daily life and weight-related stigma triggering prolonged stress responses. ACEs, impacting both obesity and stress, are significant individual-level factors influencing this relationship, and their effects are observed even in older adulthood. Studies show that ACEs can result in prolonged stress responses linked to toxic stress.

This longitudinal study used data from the Canadian Longitudinal Study on Aging (CLSA) COVID-19 Study, encompassing 23,972 adults aged 50–96. Pre-pandemic data (2015–2018) on obesity and ACEs were collected. Stress was measured using the COVID-19 Exit Survey (Sept-Dec 2020). Obesity was categorized using World Health Organization standards. ACEs were assessed based on 11 experiences before age 16 (or 18 for some events) using a cumulative score. Stress was measured through stressors (categorized into health, resources, caregiving domains) and perceived pandemic consequences (negative/very negative vs. others). Logistic, Poisson, and negative binomial regression were used to estimate relative risks (RRs) and 95% confidence intervals (CIs). Interaction effects of ACEs on the obesity-stress association were evaluated on additive and multiplicative scales, utilizing relative excess risk due to interaction (RERI) and ratio of relative risk (RRR). The analysis adjusted for confounders like age, race, physical activity, income, alcohol consumption, and depression. A BMI correction equation was applied to self-reported BMI data to account for biases associated with self-reporting.

Individuals with obesity had a significantly increased likelihood of experiencing more stressors (class III obesity vs. healthy weight: aRR = 1.67; 95% CI = 1.12–2.39). This dose-response relationship was consistent across total stressors and health and resource domains. However, obesity's association with stress was not modified by ACEs. A strong dose-response relationship existed between ACEs and stress outcomes, with individuals experiencing more ACEs reporting more stressors and perceiving the pandemic's consequences more negatively (4–8 ACEs vs. none RR = 1.32; 95% CI: 1.19–1.47). There was limited evidence of interaction between obesity and ACEs in influencing stress outcomes. Sex modified the obesity-stress association; females with class III obesity reported fewer stressors than males. Sensitivity analyses showed similar findings for maltreatment and family dysfunction ACEs.

The findings highlight the increased stress experienced by individuals with obesity during the pandemic. The absence of interaction between obesity and ACEs suggests that ACEs may not modify the already elevated stress risk in individuals with obesity. The independent association of ACEs with increased stress underscores the long-term effects of childhood adversity on stress responses to major life events. Sex differences in stress responses suggest potential biological and/or sociocultural factors. The lack of ACE modification could be due to the study's timeframe, population (older community-dwelling adults), or assessment timing. Weight bias stemming from pandemic media coverage might have exacerbated stress among individuals with obesity. Future research needs to delve deeper into the mechanisms behind these associations, especially regarding weight bias and the differential stress response linked to obesity and ACEs. Targeted interventions and coping mechanisms could help mitigate the cyclical relationship between stress and obesity.

This study revealed increased stress during the COVID-19 pandemic among individuals with obesity or ACEs, but ACEs did not modify the obesity-stress link. Future research should explore the long-term consequences of pandemic stress and investigate mechanisms underlying the associations, potentially informing targeted interventions. The sex difference in the relationship between obesity and stress warrants further investigation.

The study's limitations include a predominantly white sample, the use of self-reported recall for ACEs and stressors, the use of a 2005 BMI correction equation, and the potential for selection bias due to the age range and participation limitations of the CLSA sample. The relatively early assessment of pandemic stress (Sept-Dec 2020) might not capture the full range of experiences.