A systematic analysis of global anemia burden from 1990 to 2010

Abstract

Previous studies of anemia epidemiology have been geographically limited with little detail about severity or etiology. Using publicly available data, we estimated mild, moderate, and severe anemia from 1990 to 2010 for 187 countries, both sexes, and 20 age groups. We then performed cause-specific attribution to 17 conditions using data from the Global Burden of Diseases, Injuries and Risk Factors (GBD) 2010 Study. Global anemia prevalence in 2010 was 32.9%, causing 68.36 (95% uncertainty interval [UI], 40.98 to 107.54) million years lived with disability (8.8% of total for all conditions [95% UI, 6.3% to 11.7%]). Prevalence dropped for both sexes from 1990 to 2010, although more for males. Prevalence in females was higher in most regions and age groups. South Asia and Central, West, and East sub-Saharan Africa had the highest burden, while East, Southeast, and South Asia saw the greatest reductions. Iron-deficiency anemia was the top cause globally, although 10 different conditions were among the top 3 in regional rankings. Malaria, schistosomiasis, and chronic kidney disease-related anemia were the only conditions to increase in prevalence. Hemoglobinopathies made significant contributions in most populations. Burden was highest in children under age 5, the only age groups with negative trends from 1990 to 2010.

Figure 1

Flowchart of modeling process for calculating anemia burden. Illustration of the process used for first calculating the total amount of anemia present in each country, age, sex, and year (the anemia “envelope”), then apportioning it to individual causes of anemia in a hierarchical, mutually exclusive, and evidence-based approach. DHS, Demographic and Health Surveys; HgB, hemoglobin; IHME, Institute for Health Metrics and Evaluation; Lowess R.E., locally weighted scatterplot smoothing random effects regression; NOS, not otherwise specified; OLS, ordinary least squares; PfPR, Plasmodium falciparum parasite rate; VMNIS, Vitamin and Mineral Nutrition Information System.

Figure 2

Global anemia prevalence, total YLD, and mean DW, by severity, from 1990 to 2010. Global anemia burden was calculated for each year from 1980 through 2010 (1980-1990 not shown). Prevalence rates decreased from 40.2% to 32.9% from 1990 to 2010. Roughly two thirds of this decrease can be attributed to decreased sex- and cause-specific rates of diseases that lead to anemia. The remaining one third of the decrease was associated with population aging. Total anemia burden, as measured in YLD increased from 65.5 to 68.3 million YLD (8.8% of global total from all conditions) from 1990 to 2010. Without dramatic decreases in age-, sex- and cause-specific disease rates, population growth would have led to a much greater increase in total anemia YLD. Mean severity of anemia cases, as measured by mean DW, decreased for females from 1990 to 2010, but not for males.

Figure 3

Global and regional cause-specific anemia prevalence for 1990 and 2010. Prevalence of anemia for both males and females decreased from 1990 to 2010. The largest improvements for males were in anemia resulting from hookworm and iron deficiency, while the largest percentage gains for females were in iron deficiency and maternal hemorrhage. Regional differences in proportion of cases resulting from specific causes varied widely. Malaria was a major cause of anemia in many regions, but none more so than West sub-Saharan Africa, where it accounted for 24.7% of all prevalent anemia. South and East Asia, despite being among those regions with the greatest reductions in anemia, had more than half the world’s anemia cases. Anemia prevalence in 2010 generally increased with decreasing regional mean age of death. Prevalence was highest in East, Central, and West sub-Saharan Africa. These regions also saw the least improvement among all low- and middle-income regions between 1990 and 2010. AP, Asia Pacific; Cent, central; Eur, Europe; G6PD, glucose-6-phosphate dehydrogenase; hemog, hemoglobinemia; HI, high income; LA, Latin America; NA, North America; NA/ME, North Africa/Middle East; NTD, neglected tropical diseases; South, Southern; SE, Southeast; SSA, sub-Saharan Africa.

Figure 4

Global burden of anemia by age. Anemia burden by age for (A) prevalence and (B) total YLD. Those younger than age 5 years had the highest prevalence and total YLD from anemia. These age groups also had the least favorable changes between 1990 and 2010. Females had higher prevalence and total YLD than males at all ages. While anemia prevalence for females decreased steadily with age, anemia prevalence increased in older age groups among males. As demonstrated by steady decreases in total YLD, however, those prevalent cases among males tended to be less severe. Improvements in anemia prevalence and total YLD for males between 1990 and 2010 were more substantial than those for females although not statistically significant.

Figure 5

Total YLD resulting from all causes of anemia by country. YLD resulting from all causes of anemia are presented as per capita results for 2010. The percentage change in anemia burden from 1990 to 2010 by country is shown in the bottom panel. West and Central sub-Saharan Africa along with South Asia had the highest rates of anemia-related disability in 1990. Many African countries still had very high rates of anemia YLD in 2010 and made comparatively little progress in reducing anemia in the intervening two decades. Many countries did make significant progress, however, including all countries in East and South Asia, much of the Middle East, as well as parts of central Latin America. ATG, Antigua and Barbuda; BRB, Barbados; COM, Comoros; DMA, Dominica; FJI, Fiji; FSM, Federated States of Micronesia; GRD, Grenada; KIR, Kiribati; LCA, Saint Lucia; MDV, Maldives; MHL, Marshall Islands; MLT, Malta; MUS, Mauritius; SGP, Singapore; SLB, Solomon Islands; SYC, Seychelles; TLS, Timor-Leste; TON, Tonga; TTO, Trinidad and Tobago; VCT, Saint Vincent and the Grenadines; VUT, Vanuatu; WSM, Samoa.