Associations between social adversity and young children’s hair cortisol: A systematic review, 2021, Bryce et al

Abstract
Psychosocial and socioeconomic adversity in early childhood (termed ‘social adversity’) can have lifelong detrimental effects on health and development.

Physiological stress is one proposed mechanism by which social adversity ‘gets under the skin’. There is substantial research interest in whether hair cortisol, a biomarker proposed to measure the cumulative physiological stress response over time, can illustrate this mechanism. As a result, a growing number of studies have tested for associations between indicators of social adversity and child hair cortisol.

The aim of this paper is to conduct a comprehensive, systematic review of the evidence for associations between indicators of social adversity and hair cortisol, specifically in young children (birth to 8 years) published any time up to 31 December 2019. The literature search identified 44 published studies that met inclusion criteria. The studies examined associations between one or more indicators of social adversity and child hair cortisol across 35 independent cohorts comprising 8370 children.

Indicators of adversity examined in the identified literature included socioeconomic factors (e.g. low parental education, low income and unemployment), psychosocial factors (e.g. parent stress, poor mental health and family violence), and children’s direct exposure to maltreatment, abuse and stressful events.

Across all indicators of adversity, a total of 142 associations with hair cortisol were examined. Evidence of associations was limited and inconsistent; 34/142 (24%) showed evidence of a positive association between adversity and higher hair cortisol, 8/142 (6%) showed a negative association, and more than two thirds (100/142, 70%) of all examined associations were null.

The collective evidence appears insufficient to conclude that there is a relationship between social adversity and hair cortisol, as a measure of physiological stress response, in young children.

https://www.sciencedirect.com/science/article/abs/pii/S0306453021000500

(rt on Pariante twitter feed)
https://twitter.com/user/status/1385632341654114307

 

I'll never understand the obsession with making a common hormone with numerous functions as a marker for one specific thing. It's all so over-simplistic. Like talking about dopamine as the reward hormone even though it does many more things, or serotonin for depression. It's textbook perfect "the sparrow makes the spring" and no one lights up to it.

Zero chance this will detract anyone from continuing to say it, though. Which says everything about evidence-based medicine: no one trusts the results when they go against their expectations. Unlike in science, where falsification is considered reliable. No surprise all this entire field does is the same handful of things in loops.

 

Any allowance for age / hormonal development

Any consideration of gene expression ( its a busy molecules and mediated/ modulated by a lot)

Any checking on key elements ( such as calcium )

 

Many thanks for posting this.

Hair cortisol can only be a measure of this over lifetime of the hair. As in, my mullet is max 6 months old perhaps? So, at best it's a fairly recent measure. Of what it's anyones guess. Cortisol has many functions.

My response to Psychological Medicine re their meta analysis of 'stress' and self report of lifetime stressors and FM in adulthood I suggest that such relationships are more than likely to be a result of the methods of study, rather than an actual 'thing'.

Onwards and upwards. PwFM need to know what is the underlying causes their condition. Not some musings about the past with no objective evidence of convincing mechanisms whatsoever. Or misinterpreted strain as something pathological when being in pain is er, stressful. Who knew?

 

Childhood stress as a cause of disease should be easy to prove or disprove. Some children grow up in situations of intense stress. Rates of FM, ME and FND should be very, very high in refugees for instance. People are very willing to help others so it should not be difficult to find subjects with a known past history.

Instead, they take people with a disease and then work back when they should look for disease in people with known stressful childhoods.

 

There is some research in this area. Prospective studies do not support the so called link between retrospective fishing for 'stressors' and, for example, FM.

I have some examples and rationale in my upcoming Correspondence in Psychological Medicine Not long now until this is published