Late-life depression symptom profiles are differentially associated with immunometabolic functioning.

Growing evidence suggests immune and metabolic dysregulation among depressed persons, possibly restricted to specific subgroups. This study explores the association between depressive disorders and characteristics with immunometabolic functioning among older persons. Data are from the baseline assessment of the Netherlands Study of Depression in Older Persons, including 131 non-depressed and 358 depressed (6-month DSM-IV major depressive disorder) persons (60-93 years). Immune (C-reactive protein, interleukin [IL]-6) and metabolic (waist circumference, triglycerides, high-density lipoprotein cholesterol, blood pressure, fasting glucose) factors were measured. Depression characteristics included severity, age of onset, symptom profile (atypical/melancholic) and antidepressant use. Depressed persons showed lower IL-6 levels compared with non-depressed persons. Depressed persons, except those with atypical depression, had lower waist circumference, lower glucose levels and scored lower on an overall index including all immunometabolic factors. Low waist circumference was more pronounced among those with less severe depression and those with a later age of onset, whom also had lower blood pressure levels. Atypical depression was associated with higher triglyceride levels. Antidepressant use was not clearly associated with immunometabolic functioning. To conclude, contrary to our expectations, we found overall immunometabolic downregulation in older depressed persons, in particular among those with less severe symptoms and those with late-life onset. However, persons with atypical depression presented with metabolic upregulation compared with other depressed persons. Taking depression symptom profiles into account is important when examining biological dysregulation in late-life depression.