Levels of cognitive impairment commonly found in community studies give rise to an increased risk of mortality, and this appears to be true even for quite mild levels of impairment. The analysis confirms the increased risk of mortality for dementia, but reveals a dearth of information on the causes of the excess mortality and on possible effect modification by age, dementia subtype or other variables.

Among the elderly, the prevalence of Alzheimer's disease and multi-infarct dementia, as opposed to depression, increases steeply with age. The overlap found between dementia and depression may have nosological implications. There could be an effect of lower education levels on psychiatric morbidity, particularly on depression.

The studies show that diagnosed depression in community-resident older people is associated with increased mortality. The picture for sex differences is still unclear.

The association between physical health and depressive symptoms in later life is consistent across western Europe.

Stability of the global prevalence of dementia in the elderly population has been documented. However, the decreased prevalence found in elderly men stimulated environmental hypotheses.

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BackgroundThis study describes the prevalence of dementia and major dementia subtypes in Spanish elderly.MethodsWe identified screening surveys, both published and unpublished, in Spanish populations, which fulfilled specific quality criteria and targeted prevalence of dementia in populations aged 70 years and above. Surveys covering 13 geographically different populations were selected (prevalence period: 1990-2008). Authors of original surveys provided methodological details of their studies through a systematic questionnaire and also raw age-specific data. Prevalence data were compared using direct adjustment and logistic regression.ResultsThe reanalyzed study population (aged 70 year and above) was composed of Central and North-Eastern Spanish sub-populations obtained from 9 surveys and totaled 12,232 persons and 1,194 cases of dementia (707 of Alzheimer's disease, 238 of vascular dementia). Results showed high variation in age- and sex-specific prevalence across studies. The reanalyzed prevalence of dementia was significantly higher in women; increased with age, particularly for Alzheimer's disease; and displayed a significant geographical variation among men. Prevalence was lowest in surveys reporting participation below 85%, studies referred to urban-mixed populations and populations diagnosed by psychiatrists.ConclusionPrevalence of dementia and Alzheimer's disease in Central and North-Eastern Spain is higher in females, increases with age, and displays considerable geographic variation that may be method-related. People suffering from dementia and Alzheimer's disease in Spain may approach 600,000 and 400,000 respectively. However, existing studies may not be completely appropriate to infer prevalence of dementia and its subtypes in Spain until surveys in Southern Spain are conducted.

Aims/hypothesis Although several studies have reported on the association between diabetes and depression, none have used both formal psychiatric criteria and a prospective, population-based design. Therefore, it remains unclear whether diabetes is a risk factor for the development of depression. Moreover, it is not clear if this effect is influenced by other chronic diseases and functional disabilities. Methods A large (n=4,803) representative communitybased study in Spanish elderly subjects (at least 55 years of age) was conducted. The presence of major depression was assessed by means of a standardised psychiatric diagnostic interview (Automated Geriatric Examination for Computer Assisted Taxonomy). Subjects underwent a baseline assessment and a follow-up assessment after 2 and 5 years to determine the incidence of depression. Results At baseline 597 subjects (12.5%) were identified as having diabetes. Prevalence and incidence of depression in cases of diabetes were 15.4% and 16.5% respectively. Diabetes was associated with an increased risk of prevalent (odds ratio [OR]=1.47; 95% CI: 1.16-1.83) and incident (OR=1.40; 95% CI: 1.03-1.90) depression. Controlling for potential confounders did not essentially change these findings (prevalent depression: OR 1.41, 95% CI: 1.08-1.83; incident depression: OR 1.26, 95% CI: 0.90-1.77). Conclusions/interpretation In a large, representative prospective population-based sample using strict psychiatric criteria, we confirmed previous findings that diabetes is associated with an increased risk of depression. The effect on the incidence of depression suggests that diabetes may play a role in the development of depression in the elderly. The presence of comorbid medical diseases seems to decrease the effects of diabetes on the risk of prevalent depression, but to increase the risk of incident depression.