Do Stressed Mothers have Heavier Children? A Meta‐Analysis on the Relationship Between Maternal Stress and Child Body Mass Index

In 2007–2008, 9.5% of infants and toddlers in the United States and 16.9% of children aged 6 to 19 years were estimated to be obese 1. Child obesity prevention programs typically emphasize making changes to children’s diet and physical activity behaviors, and such programs have shown moderate success 2, 3. Although including child caretakers has been recommended for boosting obesity prevention program success, 4 targeting specific changes in mothers’ behaviors has not often been a focus of childhood obesity prevention programs. Programs that have targeted parenting practices, such as child-feeding strategies, rarely address issues such as parents’ depression, emotional distress, or anxiety 5. Yet parents of overweight and obese children report higher rates of negative emotions 6, 7. Growing evidence suggests that mothers’ psychological stress is associated with children’s decreased consumption of fruits, vegetables and high-calcium foods 8, as well as lower physical activity parenting, perceived lower importance of child physical activity, and higher child sedentary behavior 9, 10. These behaviors increase children’s risk for obesity or compromised nutritional status 5, 7, 11–17. Studies examining different facets of parental stress such as social, financial, and parenting stress show associations with increased rates of obesity in children 15, 17, 18. However, not all studies find a significant relationship between parental stress and child obesity risk.19–21 Conflicting findings underscore the need for conclusive, summative evidence. Untested moderators such as type of maternal stress, child’s own experience of stress, and child age may account for the observed inconsistencies in the size and direction of the association between maternal stress and child obesity. In particular, mothers’ stress that is specifically tied to parenting may be associated with child obesity risk in ways that differ from other types of stress. Parenting stress is characterized by feelings of distress combined with a dysfunctional parent-child relationship and a difficult child. 22, 23 Parenting stress has been shown to interact with parenting behaviors, 24 but whether its effect on child obesity risk is stronger than that of generalized stress remains an open question. In addition, children’s experience of stress may exacerbate the effects of maternal stress on children’s obesity risk. In children, chronic stress repeatedly activates the hypothalamic-pituitary-adrenal axis (HPA) and release of stress hormones (e.g., glucocorticoids), which are associated with subsequent metabolic syndrome, including visceral adiposity, with particularly damaging effects during crucial stages of brain development 25–27. Stressors experienced by the child, such as maltreatment and abuse, have been associated with higher rates of concurrent and subsequent obesity 28, 29. Finally, child age may moderate the relationship between maternal stress and child obesity, with a smaller effect for older children. Although parent feeding practices play an important role in child eating behaviors, childcare and school settings have an increasingly strong influence as children spend more time away from home with age 30. Peers and media also contribute to child dietary consumption patterns 31, and media exposure may increase as children age. For infants, the introduction of solid foods creates variability in their diet, and consistent provision of healthy foods in appropriate quantities could be disrupted by maternal stress. Child age could be a proxy for these types of changes, reducing the effect of maternal stress on the incidence of child obesity risk for older children. The current meta-analysis synthesized data from cross-sectional and longitudinal studies measuring the association between maternal stress and child obesity in order to estimate an overall effect size and test moderators of the effect. Data from cross-sectional studies were expected to provide evidence about whether there are concurrent, but not necessarily directional, associations between stress and obesity. Results from longitudinal studies were expected to shed light on whether maternal stress, especially coupled with children’s stress or present during critical periods of development, increased children’s subsequent obesity risk. Based on the existing evidence, we hypothesized that the effect size for maternal stress and child BMI would be (a) positive, (b) larger when children would have also experienced the stressor, and (c) smaller for older children.