Accumulated and differential effects of life events on cognitive decline in older persons: depending on depression, baseline cognition, or ApoE epsilon4 status?

OBJECTIVES: The study examined the accumulated as well as the differential influence of negative life events on cognitive decline in older persons, and whether this association was different for persons with normal and poor cognitive functioning, and for ApoE ε4 carriers and noncarriers. METHODS: We used data from the Longitudinal Aging Study Amsterdam (N = 1,356). Data were analyzed using linear mixed models. RESULTS: We found differential associations for different negative life events with cognitive decline none of which were mediated by depressive symptoms. The death of a child or grandchild, which may be considered a highly stressful event, was associated to a higher rate of cognitive decline, whereas more chronic stressors, such as the illness of a partner or relative, or serious conflicts, were associated with better cognitive function. The associations between life events and cognitive function were stronger in ApoE ε4 carriers compared with noncarriers, suggesting that this gene plays a role in the association between stress and cognitive function. DISCUSSION: Highly stressful events seem to be associated with a higher rate of cognitive decline, whereas mild chronic stressors may have an arousing function that stimulates cognitive performance.