Risk factors for depression in later life; results of a prospective community based study (AMSTEL)

Background: Depression in the elderly was found to be associated with a var iety of risk-factors in cross sectional designs. Based on the vulnerability -stress model, etiologic pathways for depression have been suggested, with vulnerability modifying the effect of stress factors. The current prospecti ve study tests an etiologic model for depression incidence, by assessing mo difying effects of three types of vulnerability: genetic/familial vulnerabi lity, organic vulnerability, and environmental vulnerability. Methods: 1940 non-depressed community-living elderly were interviewed at baseline, and a t follow-up three years later. Bivariate and multivariate relationships bet ween risk factors and incident depression (GMS-AGECAT) were studied. Result s: Higher age, personal history of depression, death of spouse, health rela ted factors and comorbid organic or anxiety syndrome showed significant biv ariate associations with depression incidence. In multivariate analysis, th e effect of stress factors on incident depression was not modified by a gen etic/familial vulnerability, nor by an organic vulnerability. Effect modifi cation by environmental factors was however evident; having a marital partn er, and if unmarried having social support, significantly reduced the impac t of functional disabilities on the incidence of depression. Limitations: T he study consisted of two measurements with a three years interval, depress ive episodes with a short duration may be under-represented. Conclusions: I n the elderly, the effect of stress on incident depression is modified by e nvironmental vulnerability. No evidence was found of effect modification by either genetic/familial or organic vulnerability. The results have implica tions for both recognition and treatment of late-life depression. (C) 2000 Elsevier Science B.V. All rights reserved.