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A new study by researchers at Children's Hospital of Philadelphia (CHOP) shows that the cumulative "wear and tear" of the body, known as allostatic load (AL), can be measured in early adolescence, and that childhood adversity correlates with increased stress and mental health problems in adolescence. The findings were published today in the journal Nature Mental Health.

Since the onset of the COVID-19 pandemic, children and adolescents have faced increasing mental health challenges. Driven by a strong commitment to addressing the childhood mental health crisis, CHOP researchers sought to quantify how the exposome, an environmental exposure, “gets under the skin” and influences physiological systems and mental health, and how differences in the exposome may explain health disparities. The authors also explored gene-environment mechanisms leading to AL to better understand how stress affects physical and mental health, which could improve prevention and intervention strategies.

"The conventional wisdom is that if you're chronically stressed, your body pays a price, but it happens over time," said Dr. Ran Barzilai, a psychiatrist at the Center for Youth Suicide Prevention, Intervention, and Research at CHOP and lead author of the study. "Our data show that, although less developed, we can quantify AL in adolescents as early as age 12 and link it to childhood adversity and inequality."

In a study led by Kevin Hoffman, M.D., a child and adolescent psychiatrist at CHOP, the team analyzed data from more than 5,000 diverse adolescents, with an average age of 12, from the longitudinal Adolescent Brain Cognitive Development Study. They calculated a latent AL score using body mass index, waist circumference, blood pressure, blood glycosylated hemoglobin levels, blood cholesterol levels, and salivary levels of the hormone dehydroepiandrosterone (DHEA).

Childhood exposome risks were determined by analyzing their environment up to age 11 years through lifestyle factors such as diet, exposure to violence, poverty, and pollutants. Genetic risk was assessed using polygenic risk scores for metabolic problems such as type 2 diabetes (T2D) and psychiatric conditions such as major depressive disorder (MDD).

Using linear mixed-effects models, the researchers assessed the interactions between exposome and polygenic risks and their impact on AL. Overall, they found that the association between childhood environmental exposures and adolescent AL was stronger in individuals with higher genetic risk for T2D and MDD. The study also found that environmental factors such as childhood adversity, including violence, family dysfunction, and poverty, increased AL, which in turn impacted adolescent mental health.

"These findings extend the existing literature suggesting a mediating role for AL from childhood adversity to adult mental health and support the hypothesis that AL may be a mechanism contributing to health inequalities," Barzilai added. "Importantly, we show evidence of inequalities in AL early in life, long before the expected onset of many chronic medical conditions."

For example, non-German white youth had significantly lower AL compared to Hispanic and non-German black youth. Childhood environmental stressors, such as daily difficulties in the home and community, were associated with higher AL in adolescence.

Given the significant health inequities in America, the researchers hope these findings will spur more research in diverse populations where AL measurements can improve understanding of differences in childhood health outcomes and related inequities.

"The future of mental health is precision medicine, which enables a comprehensive understanding of how individual and structural environments, as well as genes, contribute to health outcomes early in life, both physically and mentally," Barzilai said.

Source: Medical Xpress