Exposure to toxic stress in childhood is associated with adult health inequities. Last fall, the Medical Care Section’s Health Equity Committee organized a special panel presentation on the topic at the 2016 APHA Annual Meeting, which we’re highlighting in a series of posts. The first post is here.
The link between childhood adversity and toxic stress was the topic of the presentation by Donald A. Barr, MD, PhD, Professor of Pediatrics in the Stanford School of Medicine, and in the Graduate School of Education by courtesy. Dr. Barr first spent time reviewing the biological and physiological systems involved in the stress response and introducing the idea of allostatic load.
Elevated salivary cortisol levels have been detected in disadvantaged children of all ages — teenagers, kindergarteners, even 2-4 year olds. Chronically elevated cortisol can lead to:
- Increased inflammatory markers in the blood
- Inflammation in cells lining the inner wall of small arteries
- Scarring of the walls of the blood vessel
- Increased stiffness of the walls of the blood vessel
- Increased carotid intima-media thickness (IMT) – a surrogate marker for atherosclerosis
Chronically elevated levels of cortisol can also have toxic effects on neurological development in young children. This includes executive function, which helps us plan, follow directions, and resist impulsive urges — tasks that are essential to academic achievement.
Chronic stress is also associated with overdevelopment and overactivity [PDF] in the amygdala and orbitofrontal cortex as well as loss of neurons and neural connections in the hippocampus and medial prefrontal cortex. The consequences of these changes can include greater anxiety, worsened executive function, and impaired memory and mood control. Chronic stress reduces the ability of the hippocampus to promote contextual learning, leading–at least in part–to the strong association between early adverse experiences and subsequent problems in the development of linguistic, cognitive, and social-emotional skills.
So what’s the relationship between health equity and adverse childhood experiences (ACEs)? Poverty is extremely stressful. Parental unemployment and separation are ACEs that are directly associated with poverty. Moreover, multiple studies have found that children from poorer families experience more of the other ACEs, such as physical abuse and serious neglect. Although people of color are more likely to be poor, the relationship between race/ethnicity and ACEs is complicated.
Nevertheless, the research is clear. Chronic stress is no good for anyone, at any time in the lifespan. But during childhood, it can have profound effects on development and the body’s systems. These effects, on top of the maladaptive behaviors that are often developed in response to childhood trauma, may be at least partly to blame for a whole host of adult diseases. Every disease that is thought to be related to inflammation – heart disease, musculoskeletal problems, diabetes, and so on – may be linked to the destructive effects of toxic stress.
In closing, Dr. Barr said:
We should view the chronic elevation in cortisol that results from high levels of stress in early childhood as a toxin, as potentially harmful to young children as lead or other toxins, take steps to identify children at risk, and adopt interventions shown to reduce stress.
But he also cautioned against overly pessimistic attitudes about children who have experienced serious adversities. There are opportunities for interventions at every stage in the lifespan. Ideally, we should teach children as early as possible about how to deal with stress. However, everyone can benefit from adopting better stress management practices, at any age. To that end, here are some stress management tips for children and adults.
Stay tuned for the next post in this series in March.
Lisa M. Lines
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