The association between depression and inflammation is inconsistent across research samples.
This study tested the hypothesis that a history of childhood maltreatment could identify a subgroup of depressed individuals with elevated inflammation levels, thus helping to explain previous inconsistencies.
Prospective longitudinal cohort study.
A representative birth cohort of 1,000 individuals was followed to age 32 years as part of the Dunedin Multidisciplinary Health and Development Study. Study members were assessed for history of childhood maltreatment and current depression.
MAIN OUTCOME MEASURES
Inflammation was assessed by a clinically-relevant categorical measure of high-sensitivity C-reactive protein (hsCRP >3mg/L), and a dimensional inflammation factor indexing the shared variance of continuous measures of hsCRP, fibrinogen, and white blood cells.
Although depression was associated with high hsCRP (RR=1.45; 95%CI=1.06;1.99), this association was significantly attenuated and no longer significant when the effect of childhood maltreatment was taken into account. Individuals with current depression and childhood maltreatment history were more likely to show high hsCRP levels than controls (N=27; RR=2.07; 95%CI=1.23;3.47). In contrast, individuals with current depression only showed a non-significant elevation in risk (N=109; RR=1.40; 95%CI=0.97;2.01). Results generalized to the inflammation factor. The elevated inflammation levels in depressed+maltreated individuals were not explained by correlated risk factors, such as depression recurrence, low socioeconomic status in childhood or adulthood, poor health, or smoking.
A history of childhood maltreatment contributes to the co-occurrence of depression and inflammation. Information about experiences of childhood maltreatment may help to identify depressed individuals with elevated inflammation levels and thus cardiovascular disease risk.