Causes of recurrent or persistent anemia in older people from the results of the São Paulo Ageing & Health Study.

Aim: Anemia is a prevalent condition in older people, and associated with increased morbidity and mortality. Previous studies identified various causes of anemia in this population. We aimed to determine the frequency and main causes of persistent or recurrent anemia in participants 2 years after their inclusion in the São Paulo Ageing & Health Study (SPAH).

Methods: The SPAH is a cohort study of 2072 individuals aged 65 years or older living in poor neighborhoods of São Paulo, Brazil. A total of 2 years after inclusion, participants were reassessed; those with anemia at baseline were eligible for this ancillary study. Individuals were invited to a medical re-evaluation, including taking blood samples to determine serum iron, ferritin, total iron-binding capacity, folic acid, vitamin B(12), creatinine and transferrin saturation levels, and blood cell and reticulocyte counts. Anemia diagnosis was based on WHO criteria. Information about cause of death before follow-up assessment was obtained from death certificates.

Results: Of the 203 participants with anemia at inclusion, 97 (47.8%) were reassessed, 48 (23.6%) died before follow-up assessment, 33 (16.3%) refused to participate and 25 (12.3%) were not traced. A total of 57 (58.8%) of the 97 re-evaluated participants had persistent or recurrent anemia. Lower baseline hemoglobin was a predictor of anemia during follow up. Major causes of persistent or recurrent anemia at follow up were renal disease (62%) and chronic inflammation (35%).

Conclusion: Anemia was a prevalent and persistent disease in this low-income sample of older individuals. Micronutrient-related anemia, chronic blood loss and renal disease are important mechanisms for perpetuating low hemoglobin levels.