Anemia is a complex public health problem caused by multiple factors. Figure 1 outlines the four main types of the immediate causes of anemia—infection, micronutrient deficiency, inflammation, and genetic red blood cell disorders—which affect the body’s ability to access, absorb, and use important nutrients and undermine red blood cell production. Food security, inadequate maternal and child care, and health services and the environment are highlighted in the left-hand side of the figure to represent the main underlying causes of anemia. Clicking on one of the four types of causes in figure 1 will take you to a page with more information on collecting and analyzing related data. Knowing the causes that contribute to the anemia burden can help you identify which actions will be necessary to prevent and control the disease in your country.
Figure 1: Anemia Causal Pathway1
How to include this information in your landscape analysis
To understand the relative importance of each cause, you must collect data that illustrate the role each cause plays in the burden of anemia. In your landscape analysis, explore which data are available for each cause of anemia, describe what is known about each potential cause, and use the information in this guidance to understand the relative importance of each cause in your context.
To illustrate the variations in your country, you can also include graphs of the prevalence of each cause by target group, or by various characteristics. Looking at these causes of anemia, over time, may help you identify whether their prevalence, and the resulting risk of anemia, has increased or decreased. Some causes may include a measure of the public health significance, which you can include in your landscape analysis. You do not need to do additional or complex analysis linking anemia to these risk factors unless your team has the epidemiological expertise. The rest of this section describes the four main types of causes of anemia and how to capture information about them in your landscape analysis. The subsequent sections of this guidance—Step 3: Review Anemia Policies and Step 4: Assess Status of Anemia Interventions—include more information on how to address anemia.
In the sections that follow, we included a number of methodological issues for each of the causes of anemia, which are important for you to understand. You should understand a number of common issues while reviewing data on the causes of anemia, and we discuss them here.
- Often, you can use more than one technique to estimate the prevalence of anemia causes (e.g., prevalence of malaria infection or iron deficiency). Data from different years or sources may use different techniques to calculate the same indicator. For each data point included in your landscape analysis, to ensure that the data are comparable and representative at the same level, note the sampling method, technique, and season when the data were gathered.
- When you interpret biomarkers, be sure to check that the biomarkers, techniques, units, and cutoff points used are consistent with the recommendations. In your report, include any differences from the current recommendations.
- In general, use population-based surveys to determine the prevalence of the causes of anemia. If not available, consider other types of surveillance data—for example, a country’s health management information system—to estimate the prevalence of the causes of anemia. However, these sources will only capture confirmed cases or diagnoses that are reported through the health care system. As a result, they are likely to underestimate the extent of the cause’s prevalence, especially because surveillance is often weakest in countries with high prevalence of the causes of anemia. The quality of data available through these data sources will vary depending on their design and the in-country capacity for monitoring.
- Many research or evaluation activities collect biomarker data. Kassebaum et al. (2014) includes a list of available data from 150 countries in supplemental tables 1 and 2 of the online appendix. For more information: www.ncbi.nlm.nih.gov/pmc/articles/PMC3907750/bin/supp_123_5_615__index.html.
- You may need to rely on research data to access information about the causes of anemia. A systematic search of electronic databases—for example, PubMed and the Cochrane libraries—may be helpful (see Box 2 in Gathering Information on Anemia). Use specific keywords for the cause you are interested in, as well as the name of the country. You can limit the search by specifying population groups of interest—women of reproductive age, pregnant women, adolescents, school-age children, young children, children, or infants. Remember, it is important to state as a limitation in your landscape analysis that the findings are linked to specific geographic areas within a country, or to specific target groups, and cannot be generalized to the whole country. Even so, these data may offer a gauge and range of the prevalence of causes of anemia within your country.