Recurrent depressive symptoms and the incidence of dementia and mild cognitive impairment

National Institute on Aging, NIA/NIH/IRP, Baltimore, MD, USA.
Neurology (Impact Factor: 8.3). 07/2010; 75(1):27-34. DOI: 10.1212/WNL.0b013e3181e62124
Source: PubMed

ABSTRACT A history of depression has been linked to an increased dementia risk. This risk may be particularly high in recurrent depression due to repeated brain insult. We investigated whether there is a dose-dependent relationship between the number of episodes of elevated depressive symptoms (EDS) and the risk for mild cognitive impairment (MCI) and dementia.
A total of 1,239 older adults from the Baltimore Longitudinal Study of Aging were followed for a median of 24.7 years. Diagnoses of MCI and dementia were made based on prospective data. Participants completed the Center for Epidemiologic Studies Depression Scale at 1- to 2-year intervals and were considered to have an EDS if their score was > or = 16. Kaplan-Meier survival curves, log-rank test for trend for survivor functions, and Cox proportional hazards models were conducted to examine the risk of MCI and dementia by number of EDS.
We observed a monotonic increase in risk for all-cause dementia and Alzheimer disease as a function of the number of EDS. Each episode was associated with a 14% increase in risk for all-cause dementia. Having 1 EDS conferred an 87%-92% increase in dementia risk, while having 2 or more episodes nearly doubled the risk. Recurrence of EDS did not increase the risk of incident MCI.
Our findings support the hypothesis that depression is a risk factor for dementia and suggest that recurrent depression is particularly pernicious. Preventing the recurrence of depression in older adults may prevent or delay the onset of dementia.

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Available from: May A Beydoun, Jul 14, 2015
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    • "A number of factors have been shown to increase gut permeability, including dietary fats [7], stress [6] and alcohol [8], including binge alcohol drinking [9], whilst a number of factors can decrease permeability or help to maintain gut tight junction integration, including dietary whole grains [10] and melatonin [4], with the latter preventing the effects of alcohol on gut permeability [8]. Recent work on the role of gut permeability in other medical conditions has focussed on its impact in the aetiology and course of depression, in turn driving the association of recurrent depression with other medical conditions, including Alzheimer's disease [11]. As such, we will first look at the role of gut permeability in depression, linking this to the aetiology of depression-associated conditions. "
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    • "In order to specify this correlation, the Baltimore Longitudinal Study of Aging followed 1,239 old adults for a median period of 25 years, and showed that having one severe MDE leads to an 87% increased risk of dementia (hazard ratio; 1.87). On the same basis, having two or more episodes nearly doubled the risk (hazard ratio; 2.08), and each episode was associated with a 14% increased risk of dementia (Dotson et al., 2010). One of the suggested mechanisms that may bind depression and dementia is the reduced size of the hippocampus, which is known as one of the components of Alzheimer's dementia diagnosis. "
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