Child Emotional Abuse and Inflammation in Young Adults

Background and Purpose: Victims of child maltreatment have a higher risk of developing adult chronic health conditions including cardiovascular diseases (CVD). Risky health behaviors do account for some of the association between child maltreatment and CVD, however, traumatic childhood experiences predict CVD net of behavioral risk factors. C-reactive protein (CRP), a biological marker of systemic inflammation is a known predictor of CVD and may be one biological mechanism that links child maltreatment to CVD later in life. While previous studies have linked cumulative measures of childhood adversity to higher levels of CRP, fewer studies have examined the effect of specific subtypes of child maltreatment. This purpose of this study is to test for an association between child emotional abuse and systemic inflammation (CRP) independent of experiences of physical and sexual abuse.

Methods: Data come from the National Longitudinal Study of Adolescent to Adult Health (Add Health), a nationally representative longitudinal survey of adolescents enrolled in grades 7-12 in the 1994-95 academic year. The analytic sample includes young adults who completed in-home interviews at Waves I, III and IV with valid sample weights and valid measures of CRP at Wave IV. Women who were pregnant at Wave IV (N=421) were excluded due to the impact of pregnancy on hormone production and regulation and CRP values greater than 10 mg/L were excluded (N=1,192) as it is indicative of an active infection. The final sample consists of 9,268 young adults.

Measures: The outcome variable, CRP is operationalized as a continuous variable with values ranging from 0.28mg/L to 10mg/L. To approximate normal distribution, CRP was log transformed. The main predictor of interest, experiences of emotional abuse prior to age 18 were categorized as “This never happened to me” (omitted reference), “Once or Twice”, “Three to Five times” and “Six or more times”.  We accounted for risky health behavior (smoking status) physical risk factors (BMI, depressive symptoms, use of anti-inflammatory medications) and childhood exposure to physical and sexual abuse. Analyses included age, race/ethnicity, education and income.

Analytic approach: T-tests and corresponding adjusted Wald test was used for all bivariate analyses and weighted regression models were used to estimate the effect of emotional abuse on CRP. Starting with the most parsimonious model, theoretically similar variables were introduced into the model in a sequential manner and parameter estimates of new models were compared to estimates of previous models to assess model fit. All analyses were conducted using the survey (svy) command in Stata 13 to account for the complex sample design and unequal probability of selection.

Results: After adjusting for exposure to physical and sexual abuse young adults who experienced chronic emotional abuse in childhood had significantly higher CRP levels. Findings support investigation of child emotional abuse as a physiologically damaging form of child maltreatment.

Conclusions and Implications: Findings from this study support for example, the importance of not only probing for cumulative exposure to adverse childhood experiences in clinical settings but also dis-aggregating different sub-types of maltreatment.