The ECA literature suggests that early trauma exposure is salient and detrimental for most of those who experience it. However, some people who are exposed to ECA do not experience notable physical or psychological consequences, and there appears to be evidence for some heterogeneity in individual responses (Shonkoff, Boyce, & McEwen, 2009) . Individual differences might impact the relation between ECA and physical health and contribute to this heterogeneity, including resilience, education and/or intelligence, and social support .

Resilience is a well studied and complex protective factor and comprises the ability to respond in an adaptive manner when faced with trauma (see Chap. 16, this volume, for related discussion). Some aspects of resiliency are considered to be individual-level factors, such as coping skills and IQ, while other protective factors are external, including parental monitoring, appropriate family functioning, and having a larger number of adults in one’s home (Tiet et al., 1998) . Individuals higher in resilience experience fewer problems after ECA exposure. For example, resilience has been shown to reduce the tendency for hazardous alcohol and illicit drug use in those exposed to ECA (Wingo, Ressler, & Bradley, 2014) . However, recognition of the protectiveness of individual resiliency should not serve to alleviate society’s role in the reduction of ECA nor its obligation to victims. In fact, even in those youth labeled as resilient, evidence can still be found to suggest physiological effects of ECA exposure (Brody et al., 2013) . Therefore, although resilience may help individual children weather the storm of adversity, it is important to also consider broader societal factors that contribute both to the prevalence and consequences of ECA exposure.

Higher intelligence or higher levels of education have also been shown to impact ECA exposure consequences . For example, higher IQ and higher educational aspirations were associated with better adjustment in youth (Tiet et al., 1998) . However, other studies have suggested that education is not enough to ameliorate the risks associated with ECA. For example, Montez and Hayward (2014) found that higher education did not remove all consequences of early disadvantage, in that those with disadvantaged childhoods still lived shorter and more impaired lives . However, evidence was found for the benefit of upward mobility, in that those from a disadvantaged background that obtained higher education experienced similar or better outcomes on average than advantaged individuals with lower educational attainment. In addition, in a study of male medical doctors, it was found that those raised in a low-SES household had a greater risk of developing coronary heart disease before the age of 50 (Kittleson et al., 2006) .

Finally, social support or the presence of a supportive adult, is a major factor influencing the physiological effects of ECA. Whereas the lack of a supportive adult can be considered an adversity, the presence of at least one stable and healthy relationship with an adult can protect against the harmful effects of ECA (see Chap. 1, this volume, for related discussion) . These relationships have been termed safe, stable, nurturing relationships (or SSNRs, see Schofield, Lee, & Merrick, 2013) . As one example in a recent study, the presence of a supportive role model in children of low-SES backgrounds predicted lower IL-6, though this relation was partially explained by patterns of optimistic thought (Chen, Lee, Cavey, & Ho, 2013) . In addition, because so many adversities are predicated on the dysfunction of close adults, a more stable adult influence may ameliorate these negative effects, including by stopping the abuse or neglect altogether or simply by providing the child with material needs or affection. Therefore, the presence or absence of a supportive relationship is a very important individual difference impacting how children might respond to ECA exposure .

The literature linking ECA and physical health is both compelling and complex; however, avenues for improvement exist. Although the evidence provides substantial support for a linkage between ECA and poor health, evidence is often presented piecemeal and without a consideration of interactions among mental and physical health. In addition, more precision should be instituted into the measurement of ECA. Categorizing stressors into whether they constitute a form of abuse or adversity may provide greater insight into exactly which kinds of trauma are predictive of which outcomes. A greater focus on developmental factors including “age, timing, severity, and duration” of exposure (Odgers & Jaffee, 2013, p. 36) is needed. Next, a greater understanding of individual and intergenerational trajectories is important. This literature has repeatedly shown that the experience of ECA can lead to continued adversity exposure over time. In one study (Kiecolt-Glaser et al., 2011) the authors summarize their findings by stating that “childhood adversities cast a very long shadow” (p. 16) on the individual. The literature suggests that this shadow, for some, may be even longer, compromising their lifetime health and creating risky or hostile environments that shape future generations’ health much like their own. Finally, movement beyond description of the manifold ways in which ECA exposure is detrimental to health is needed; trauma researchers must continue to put these findings into action to reduce health-related disparities. As Braveman and Barclay (2009) note, it may appear as though society cannot afford to target child poverty , but with its (and other forms of ECA’s) far-reaching implications, we cannot afford to ignore it. Due to its origins in early life, ECA may serve as a physiological and psychological foundation for coping responses to all other forms of trauma an individual will experience in their life span , demonstrating its paramount importance for well (or ill)-being.