Anemia

Description

Alternative Names

Risk Factors

Although nutritional iron-deficiency anemia has declined in industrialized nations, it affects an estimated two billion people worldwide. Even in the US, iron deficiency is the most prevalent nutritional deficiency. It is highly associated with poverty, people in lower socioeconomic groups having double the risk of those who are middle or upper class.

Among Americans with iron deficiency anemia, young children have the highest risk followed by premenopausal women. Adolescent and adult men and postmenopausal women have the lowest risk. Men, in fact, are at risk for iron overload, probably because of their higher meat intake.

General Risk Factors for Anemia in Infants and Children. Up to 20% of American children and 80% of children in developing countries become anemic at some point during their childhood and adolescence. Iron deficiency is the most common cause in children, but other forms of anemia, including hereditary blood disorders, can also cause anemia in this population. African American children have the highest rates of anemia (about 25%) while other ethnic groups have an incidence under 20%.

Iron deficiency affects about 9% of children under two and about 3% of children in this age groups are anemic as a result. Children in lower-income homes are at higher risk than those in higher income homes. In a 2002 study of low-income children, ages six months to five years, the prevalence of anemia was over 10%, and was nearly 18% in children under two. It should be noted, however, that children in any income group can develop iron deficiency.

Young children nine months to 18 months have the highest risk for iron deficiency anemia in the US. Such children also are at great risk for problems in mental development from anemia. Infant boys may have a 10-fold higher risk than baby girls. In general, full-term infants who are breastfed by their mothers are born with sufficient iron stores got about six months. After that, they must rely on other sources for iron. Iron-deficiency anemia in infants and small children can be due to one or more of the following factors:

• Prematurity.
• Too early an introduction of cow's milk. (Experts recommend avoiding it for the first year of life.)
• The use of formula that isn't iron-fortified.
• The toddler's own preferences for iron-poor food.
• Low consumption of foods that enhance iron absorption, such as citrus fruits. (However, iron deficiency anemia in children has been associated with drinking too much fruit juice.)
• Strict vegetarianism in small children. (Vegetarianism may produce anemia from both low iron and B vitamin levels.)
• High fat diets in children have been associated with lower iron stores.

Better social services and more accurate ways of diagnosing and monitoring anemia are needed in these high-risk groups. There is still considerable debate on how to define iron deficiency and anemia in infants.

Risk Factors for Anemia in Premenopausal Women. In a major government study, 9% of 16% of adolescent and adult women under 49 years were iron deficient. Hispanic and African American women had double the prevalence of Caucasian women. In general, the risk for anemia in adolescent girls is about 3%. Anemia is generally mild in young women, however, and is more likely to occur with one or more of the following conditions.

• Heavy menstruation for longer than five days.
• Abnormal uterine bleeding, such as from fibroids.
• Pregnancy. About 20% of women in industrialized countries have iron deficiency during pregnancy. Multiple pregnancies and births significantly increase the risk.

Risk Factors for Anemia in Older Adults. Although a number of studies have reported that anemia is common and even underdiagnosed in older adults, middle- to upper-class older Americans are unlikely to be iron deficient. Studies suggest in fact that only about 1% of this group actually has iron deficiency anemia. (In fact, experts are concerned that many older people may be consuming too much iron, particularly from meat-rich diets. In one study, 12.9% of older middle class people had elevated iron levels, nearly all from diet.)

If anemia occurs in the elderly, it is most likely due to gastrointestinal bleeding, blood loss during surgery, chronic diseases, and folic acid and other vitamin deficiencies. Diagnosis of iron deficiency anemia, in fact, is often problematic in elderly people with chronic diseases because they often have test results that may mask the presence of actual iron deficiency.

People with Alcoholism

People with alcoholism are at risk for anemia both from internal bleeding and vitamin B deficiencies.

People with Iron-Poor Diets

Although most Americans probably consume too much iron in their diets, some people may be at risk for diet-related iron deficiencies:

• People whose diets are high in processed foods and lack any meat.
• Strict vegetarians. Vegetarians who avoid all animal products may have a slightly higher risk for deficiencies in iron and some B vitamins. Although dried beans and green vegetables often contain iron, it is less easily absorbed from plants than from meat. Fortunately, most commercial cereals are fortified with vitamin B12 and folic acid (the synthetic form of folate). Studies on the prevalence of anemia in vegetarians are weak. A 2001 study of British resident reported that anemia was more common in vegetarians than in meat eaters. One 1999 study found no significant differences in hemoglobin measurements between vegetarians and non-vegetarians, but a large percentage of both groups (18% of vegetarians and 13% of non-vegetarians) had low iron stores.

Chronic or Critical Illnesses

Anyone with a chronic disease that causes inflammation or bleeding is at risk for anemia. Critical illness in the intensive care unit is also highly associated with anemia.

Athletes

Working out regularly may cause some iron loss, which is comparable to that from menstruation and rarely worrisome. One 2000 study suggests that dietary choices may account for most cases of sports anemia. Intense, sustained exercise, such as that performed by marathon runners, may cause a condition called sports anemia, which may be due to slight gastrointestinal bleeding, damaged red blood cells, low iron intake, or poor intestinal absorption of iron.