Anemia prevalence in older subjects, causes of persistence or recurrence and its relation with dementia / Prevalência de anemia em idosos, causas de persistência ou recorrência e sua relação com demência: resultados do São Paulo Ageing and Health Study

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Anemia is a frequent disease and its prevalence increases with ageing. Relationship between anemia and dementia has been studied in the past decades, with conflicting results. This study has the following objectives: (a) To estimate, according to World Health Organization criteria, anemia prevalence in an elderly community sample in the borough of Butantã, São Paulo, Brazil; (b) To verify if anemia evolves as a persistent or recurrent disease in this population and which causes most frequently determine this evolution; and (c) To evaluate if there is an association between anemia and dementia in this population sample. 1,948 participants from the São Paulo Ageing and Health Study (Brazilian arm of the 10/66 Dementia Research Group), who had undergone a cognitive evaluation and total blood cell count at study baseline were evaluated. Anemia was found in 203 (10.4%) individuals. 777 participants (39.9%), with baseline hemoglobin levels 13.5 g/dl were invited to a reevaluation step, that occurred at a median time of 25.9 months (interquartile range: 25.1-30.9 months) after study entrance. This step consisted of a structured interview, clinical exam and blood sample collection to determine the presence and cause of anemia. Total blood cell and reticulocyte counts were performed. Serum determinations included folic acid, vitamin B12, C-reactive protein, urea, creatinine, iron, ferritin, total iron-binding capacity and transferrin saturation. For analysis purposes, these individuals were divided in two groups: (1) participants with anemia at study baseline (n=203) and (2) participants with hemoglobin levels 13.5 g/dl, but without anemia at study baseline (n=574). In group 1, 145 (71.4%) subjects completed follow-up. 40 (27.6%) were alive and without anemia; 57 (39.3%) had persistent/recurrent anemia and 48 (33.1%) died before reevaluation, mostly from cardiovascular disease or cancer. Most frequent causes of persistent/recurrent anemia were renal disease (62%), chronic inflammation (35%), megaloblastic (18%), iron-deficiency (11%), other (5%) and unexplained (12%). In group 2, 341 (59.4%) individuals completed follow-up. Anemia was incident in 34 (10.0%) of them. Most frequent causes were chronic inflammation (29%), renal disease (35%), iron-deficiency (15%), megaloblastic (12%), other (6%) and unexplained (26%). Dementia was diagnosed in 99 (5.1%) of 1,948 participants with a valid blood cell count. Univariate analysis found a positive relationship between anemia and dementia (odds ratio=2.0; 95% confidence index=1.17-3.41). However, after age- adjustment this difference vanished (odds ratio=1.33, 95% confidence index=0.76-2.33). No change occurred after adjustment for other known variables. No association between anemia and dementia subtypes Alzheimers disease, vascular dementia or other dementia was found either.

ASSUNTO(S)

anemia/epidemiologia demência dementia idoso anemia/etiologia anemia/ethiology aged anemia/epidemiology

ACESSO AO ARTIGO

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