Using publicly available data, the authors of this study estimated mild, moderate, and severe anemia from 1990 to 2010 for both sexes and 20 age groups in 187 countries. The authors found that anemia accounted for 8.8% of the total disability from all conditions in 2010, more than major depression (8.18%), chronic respiratory diseases (6.33%), and the totality of injuries (6.29%). Children <5 years and women had the highest burden. Though iron-deficiency anemia was the most common etiology globally, other leading causes of anemia varied widely by geography, age, and sex.
Kassebaum, NJ, R. Jasrasaria, M. Naghavi, SK Wulf, N. Johns, R. Lozano, M. Regan, D. Weatherall, DP Chou, TP Eisele, R. Flaxman S, L. Pullan R, SJ Brooker, and CJ Murray. "A Systematic Analysis of Global Anemia Burden from 1990 to 2010." Blood 123, no. 5 (2014): 615-24.