Association of serum interleukin-6 with mental health problems in children exposed to perinatal complications and social disadvantage

There is consistent evidence that inflammation is involved in mental disorders pathogenesis. Herein, using data from the High Risk Cohort Study for Psychiatric Disorders, we investigated the relationship between parental mood disorders (PMD), environmental factors, serum interleukin-6 (IL6) and mental health problems in children aged 6-12. We measured the serum levels of IL6 in 567 children. Information related to socio-demographic characteristics, mental health problems and multiple risk factors, as well as parent's psychiatric diagnosis, was captured. We evaluated two groups of environmental risk factors (i.e. perinatal complications and social disadvantage) using a cumulative risk model. Results showed that higher serum levels of IL6 were associated with PMD (RR = 1.072, p = 0.001), perinatal complications (RR = 1.022, p = 0.013) and social disadvantage (RR = 1.024, p = 0.021). There was an interaction between PMD and social disadvantage (RR = 1.141, p = 0.021), as the effect of PMD on IL6 was significantly higher in children exposed to higher levels of social disadvantage. Moreover, there was a positive correlation between IL6 and mental health problems (RR = 1.099, p = 0.026), which was moderated by exposure to perinatal complications or social disadvantage (RR = 1.273, p = 0.015 and RR = 1.179, p = 0.048, respectively). In conclusions, there is evidence of a differential inflammatory activation in children with PMD and exposure to environmental risk factors, when compared to matched peers. Systemic inflammation may be involved in the pathway linking familial risk and mental health problems.