Early life stress and cortisol: A meta-analysis

Area of Science:

• Endocrinology
• Psychoneuroimmunology
• Developmental Psychology

Background:

• Early life stress (ELS) is prevalent and linked to physiological dysregulation.
• Cortisol, a key stress hormone, is often studied in relation to ELS.
• Existing literature suggests a significant impact of ELS on cortisol levels later in life.

Purpose of the Study:

• To meta-analyze the relationship between early life stress (ELS) and cortisol.
• To investigate ELS effects on cortisol awakening response (CAR), baseline cortisol, non-stressed cortisol over time, and cortisol reactivity.
• To identify moderators influencing the ELS-cortisol association.

Main Methods:

• Systematic literature search of PsycINFO and PubMed for ELS and cortisol studies.
• Extraction of effect sizes for four cortisol outcome variables.
• Coding of articles for confounding variables and moderators (population, ELS, cortisol-related).

Main Results:

• No significant main effects were found between ELS and CAR, baseline cortisol, non-stressed cortisol, or cortisol reactivity.
• Significant heterogeneity was observed across the analyzed relationships.
• Abusive ELS (sexual, physical, emotional) was linked to a heightened CAR.
• ELS was associated with blunted cortisol when blood samples were used for measurement.

Conclusions:

• The commonly held belief that ELS significantly impacts later-life cortisol is challenged by the non-significant main effects.
• High heterogeneity and significant moderators suggest nuanced ELS-cortisol interactions.
• Standardized measurement of ELS and cortisol is recommended for future research.