Socioeconomic Disadvantage Moderates the Association between Peripheral Biomarkers and Childhood Psychopathology

Background Socioeconomic disadvantage (SED) has been consistently associated with early life mental health problems. SED has been shown to impact multiple biological systems, including the regulation of neurotrophic proteins, immune-inflammatory and oxidative stress markers, which, conversely, have been reported to be relevant to physiological and pathological neurodevelopment This study investigated the relationship between SED, different domains of psychopathology, serum levels of interleukin-6 (IL6), thiobarbituric acid-reactive substance (TBARS) and brain-derived neurotrophic factor (BDNF). We hypothesized that a composite of socioeconomic risk would be associated with psychopathology and altered levels of peripheral biomarkers. In addition, we hypothesized that SED would moderate the associations between mental health problems, IL6, TBARS and BDNF. Methods and Findings Using a cross-sectional design, we measured the serum levels of IL6, TBARS and BDNF in 495 children aged 6 to 12. We also investigated socio-demographic characteristics and mental health problems using the Child Behaviour Checklist (CBCL) DSM-oriented scales. SED was evaluated using a cumulative risk model. Generalized linear models were used to assess associations between SED, biomarkers levels and psychopathology. SED was significantly associated with serum levels of IL6 (RR = 1.026, 95% CI 1.0041.049, p = 0.020) and TBARS (RR = 1.077, 95% CI 1.0281.127, p = 0.002). The association between SED and BDNF was not statistically significant (RR = 1.031, 95% CI 0.9971.066, p = 0.077). SED was also significantly associated with all CBCL DSM-oriented scales (all p < 0.05), whereas serum biomarkers (i.e. IL6, TBARS, BDNF) were associated with specific subscales. Moreover, the associations between serum biomarkers and domains of psychopathology were moderated by SED, with stronger correlations between mental health problems, IL6, TBARS, and BDNF being observed in children with high SED. Conclusions In children, SED is highly associated with mental health problems. Our findings suggest that this association may be moderated via effects on multiple interacting neurobiological systems.National Council for Scientific and Technological Development (CNPq)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Sao Paulo Research Foundation (FAPESP)CNPq, Natl Inst Dev Psychiat Children & Adolescents, Sao Paulo, BrazilUniv Fed Sao Paulo UNIFESP, Interdisciplinary Lab Clin Neurosci LiNC, Sao Paulo, BrazilUniv Toronto, Mood Disorders Psychopharmacol Unit MDPU, Univ Hlth Network, Toronto, ON, CanadaPontificia Univ Catolica Rio Grande do Sul, Inst Biomed Res, Porto Alegre, RS, BrazilUniv Fed Rio Grande do Sul, Dept Psychiat, Porto Alegre, RS, BrazilUniv Texas Hlth Sci Ctr Houston, Dept Psychiat & Behav Sci, Ctr Translat Psychiat, Houston, TX 77030 USAUniv Fed Minas Gerais, Interdisciplinary Lab Med Invest, Belo Horizonte, MG, BrazilUniv Sao Paulo, Dept Psychiat, Sao Paulo, BrazilUniv Fed Sao Paulo UNIFESP, Interdisciplinary Lab Clin Neurosci LiNC, Sao Paulo, BrazilWeb of Scienc