Depressive signs in midlife : A risk factor for cognitive impairment in later life?

• Background: Although depression has been associated with dementia, the nature of this relation is still unclear. Establishing causality from previous studies has been complicated by the typical use of a short follow-up and participants aged over 70 already at baseline. The main purpose of this study was to evaluate if depressive signs already in midlife are related to cognitive impairment in later life. Methods: Participants were derived from random, population-based samples previously investigated in 1972, 1977, 1982, or 1987. Their mean age at baseline was 50.4 years (SD 6.0). After an average follow-up of 21 years, 1449 individuals (73%) aged 65 to 79 years were re-examined in 1998. At the re-examination some form of cognitive impairment was diagnosed in 139 of the participants: 82 with mild cognitive impairment and 57 with dementia (48 of these with Alzheimer’s disease). Signs of depression were estimated through responses to three questions concerning the perception of a hopeless future, impossible life goals and loneliness. The relation between depressive signs in midlife and cognitive impairment in later life was analyzed with logistic regression with adjustments for age, gender, apolipoprotein e4 status and a number of midlife health and lifestyle indicators, including blood pressure, cholesterol and marital status. Results: Depressive signs in midlife, as measured in this study, were significantly related to general cognitive impairment in later life, but also separately to both mild cognitive impairment and Alzheimer’s disease. When dichotomized into high versus low levels of depressive signs the odds ratios were 2.19 (1.1 to 4.3) for mild cognitive impairment and 3.81 (1.3 to 11.5) for Alzheimer’s disease. Significant associations were also found between the separate measures of hopelessness and loneliness on the one hand and the separate outcomes of mild cognitive impairment and Alzheimer’s disease on the other. Conclusions: The results support a causal relation between depressive signs relatively early in life and cognitive function in later life. Clinical relevance includes the long-term health implications of depressive signs in midlife also for the risk of dementia.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Neurologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Neurology (hsv//eng)

Nyckelord

Depression Epidemiology APOE

Neurology

Neurologi

Psykologi

Psychology

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