Objective: Previous studies have found associations of magnetic resonance imaging (MRI) signal hyperintensities with depression in the elderly. The present study investigates the association in a younger community sample (age 60-64 years) of depressed subjects and comparison groups for potential mediating and confounding variables.
Method: A subsample of 475 persons 60-64 years of age from a larger community survey underwent brain MRI scans. White matter hyperintensities were quantified by using an automated procedure, and basal ganglia hyperintensities were quantified by using semiquantitative visual ratings. The study also assessed depressive symptoms and use of antidepressant medication. Potential mediating or confounding variables assessed included physical disability, hypertension, stroke, diabetes, head injury, cortisol, thyroid-stimulating hormone, cognitive functioning, smoking, and alcohol use.
Results: Depressive symptoms were found to be related to total brain white matter hyperintensities but not to basal ganglia hyperintensities. However, associations disappeared when statistical adjustment was made for physical disability and smoking.
Conclusions: Depressive symptoms are related to white matter hyperintensities in mid-adult life in a community sample. Physical disability appears to play an important role in this association.