Possible connections among job stress, depressive symptoms, lipid modulation and antioxidants

Background.- Oxidative/antioxidative status may be related to psychological stress or pathogenesis of depression. Subjects and methods: Participants were selected from 381 female nurses working in a university hospital, and the Brief Job Stress Questionnaire was utilized to assess them. Nurses with high job stress (JS) (n = 18) and with low JS (it = 15) consented to participate in this study. Depressive symptoms were assessed by the Centre for Epidemiologic Studies Depression scale (CES-D). Cholesterols, lipid peroxidation (malondialdehyde, MDA) and antioxidants in the plasma were measured. Results: High JS participants exhibited significantly higher CES-D scores (t=3.34, p < 0.005), and significantly lower concentrations of total cholesterol (TC), low density+very low density lipoprotein cholesterols (LDL+VLDL), a-tocopherol, and beta-carotene compared with low is participants (t=2.69, p < 0.05; t=3.46, p < 0.005; t=2.96, p < 0.05; t=2.98, p < 0.05, respectively). However, the reductions in plasma indicators were substantially weakened after controlling for lifestyle factors with the exception of LDL+VLDL and alpha-tocopherol. In addition, the significance of alpha-tocopherol concentrations appeared to depend on cholesterol levels. CES-D scores correlated positively with plasma MDA levels, the MDA/TC ratio and the MDA/ LDL+VLDL ratio among the low JS group (r=0.69, p < 0.001; r=0.79, p < 0.001; r=0.75, p < 0.005, respectively), whereas there were no correlations among the high JS group. After controlling for lifestyle covariates, the relationship between CES-D scores and the MDA/LDL+VLDL ratio remained significant (beta=0.95, p < 0.05) using a Multiple linear regression model (F=3.61, p < 0.05). Limitations: Sample numbers in each JS group were relatively small. Conclusions.- Psychological stress may reduce the plasma levels of LDL+VLDL accompanying an a-tocopherol decrease. There appeared to be a correlation between elevated MDA and depressive symptoms in low JS participants. (c) 2005 Elsevier B.V. All rights reserved.