health disparities among children between and within racial and ethnic groups and children living across a full spectrum of SES levels limits understanding of the relative contributions and moderators of these disparities (Chen et al., 2006).
Key influences on understanding the pathways to health include a more complete knowledge of prenatal and other vulnerable periods; predisease pathways, representing the early and long-term precursors to disease; cumulative health risks across time; gene-environment interactions; and the intergenerational transmission of behaviors (NRC, 2001). Exposure to life stressors and health status are inextricably connected. For example, the effects of adverse childhood experiences, especially during critical developmental periods in childhood, on obesity and the health risks of stress and depression are areas of ongoing research (Ackard et al., 2003).
Adverse childhood experiences are an example of a set of life contexts which are experienced early in life, yet have profound effects on health and obesity risks into adulthood, independent of SES, race, and ethnicity. The Adverse Childhood Experiences (ACE) Study explored the exposures of more than 13,000 adult enrollees in a health maintenance organization to eight categories of adverse childhood experiences (e.g., abuse). The risk for obesity increased with the number and the severity of each type of childhood abuse (Williamson et al., 2002). Although the ACE Study addressed adult health outcomes rather than childhood health outcomes, the results support the hypothesis that a variety of physical, mental health, and social problems have common roots and that negative health-related behaviors may serve as coping strategies to manage the long-term consequences of childhood stress. Difficult and stressful childhood circumstances may increase the risk for mental health problems in children, which may in turn increase the risk for behaviors that contribute to childhood obesity (Goodman and Whitaker, 2002; Lumeng et al., 2003; Williamson et al., 2002). Many of these responses decrease the ability of individuals to self-regulate both physiological and emotional responses (van der Kolk and Fisler, 1994).
An improved understanding of the complex interplay of the environmental and the biological factors that influence behaviors can be achieved only through the synthesis of the findings of many scientific disciplinary perspectives. Such a synthesis of findings will allow a greater understanding of the complex web of risk factors for childhood obesity, enhance the ability to design more effective interventions, and improve the ability to develop appropriate evaluation measures (Box 3-2). Additionally, further research is needed to clarify the vulnerable periods in childhood and adolescence with particular relevance to risks for obesity and to understand how best to apply this knowledge to preventive efforts.