Pathways linking early life stress, metabolic syndrome, and the inflammatory marker fibrinogen in depressed inpatients.

BACKGROUND Previous research has shown that metabolic syndrome as well as early life stress can account for immunoactivation (e.g. in the form of altered fibrinogen levels) in patients with major depression. This study aims at assessing the relationship between components of metabolic syndrome, early life stress and fibrinogen levels, taking the severity of depression into consideration. SUBJECTS AND METHODS Measures of early life stress and signs of metabolic syndrome were collected in 58 adult inpatients diagnosed with depression. The relationships between the factors were assessed by means of path analyses. Two main models were tested: the first model with metabolic syndrome mediating between early life stress and fibrinogen levels and the second model without the mediating effect of metabolic syndrome. RESULTS The first model was not supported by our data (χ²=7.02, df=1, p=0.008, CFI=0.00, NNFI=-9.44, RMSEA=0.50). The second model however provided an excellent fit for the data (χ²=0.02, df=1, p=0.90, CFI=1.00, NNFI=2.71, RMSEA=0.00). Extending the models by introducing severity of depression into them did not yield good indices of fit. CONCLUSIONS The developmental trajectory between early life stress and inflammation appears not to be mediated by metabolic syndrome associated factors in our sample. Possible reasons including severity and type of early life stress, as well as potential epigenetic influences are discussed.