Family history of dementia and current depression in nondemented community-dwelling older adults

Prevalence and predictors of depression in populations of elderly: a review

OBJECTIVE

To offer an update on prevalence and predictors of old age depression in populations of elderly Caucasians.

METHOD

The databases MEDLINE and Psychinfo were searched and relevant literature from 1993 onwards was reviewed.

RESULTS

The prevalence of major depression ranges from 0.9% to 9.4% in private households, from 14% to 42% in institutional living, and from 1% to 16% among elderly living in private households or in institutions; and clinically relevant depressive symptom 'cases' in similar settings vary between 7.2% and 49%. The main predictors of depressive disorders and depressive symptom cases are: female gender, somatic illness, cognitive impairment, functional impairment, lack or loss of close social contacts, and a history of depression.

CONCLUSION

Depression is frequent in populations of elderly. Methodological differences between the studies hinder consistent conclusions about geographical and cross-cultural variations in prevalence and predictors of depression. Improved comparability will provide a basis for consistent conclusions.

Depressive symptoms, sex, and risk for Alzheimer's disease

Depression associates with increased risk for dementia and Alzheimer's disease (AD), although it is unclear whether it represents an actual risk factor or a prodrome. To determine the relative hazard of premorbid depressive symptomatology for development of dementia and AD, we studied risk for incident dementia and AD over a 14-year period in 1,357 community-dwelling men and women participating in the 40-year prospective Baltimore Longitudinal Study of Aging. Screening for depressive symptoms, comprehensive medical and neuropsychological evaluations were prospectively collected every 2 years. Time-dependent proportional hazards of development of AD or dementia were calculated separately for men and women, with symptoms of depression detected at 2-, 4-, and 6-year intervals before onset of dementia symptoms. Vascular risk factors were analyzed as covariates. Premorbid depressive symptoms significantly increased risk for dementia, particularly AD in men but not in women. Hazard ratios were approximately two times greater than for individuals without history of depressive symptoms, an effect independent of vascular disease. We conclude that the impact of depressive symptoms on risk for dementia and AD may vary with sex. Further studies assessing separately the role of depression as a risk factor in men and women are necessary.