RESUMO
INTRODUCTION: Anemia is a risk factor for all-cause mortality in older adults. Iron deficiency may also be associated with adverse outcomes, independent of its role in causing anemia. This study tested the hypotheses that anemia, and low ferritin among non-anemic participants, were associated with all-cause and cause-specific mortality in a community-based cohort of older adults. METHODS: Fasting blood was obtained from 5,070 ARIC participants (median age: 75) in 2011-2013. Anemia was defined by hemoglobin concentrations <12 g/dL in women and <13 g/dL in men. We classified 4,020 non-anemic participants by quartiles of plasma ferritin, measured by the SomaScan proteomics platform. Cox proportional hazards regression was used. RESULTS: Over a median of 7.5 years, there were 1147 deaths, including 357 due to cardiovascular disease (CVD), 302 to cancer and 132 to respiratory disease. Compared to those with normal hemoglobin, participants with anemia had a higher risk of all-cause mortality [hazard ratio 1.81 (95% CI: 1.60-2.06)], and mortality due to CVD [1.77 (1.41-2.22)], cancer [1.81 (1.41-2.33)], and respiratory disease [1.72 (1.18-2.52)] in demographics-adjusted models. In fully adjusted models, associations with all-cause mortality [1.37 (1.19-1.58)] and cause-specific mortality were attenuated. In non-anemic participants, lower ferritin levels were not associated with all-cause or cause-specific mortality, though associations were observed among participants with lesser evidence of inflammation and for cancer mortality in men only. CONCLUSION: Anemia is an important risk factor in older adults and may contribute to mortality due to CVD, cancer, and respiratory disease. Our results do not provide evidence that iron deficiency, independent of anemia, is a risk factor for mortality in this population.
