Generality
The World Health Organization (WHO) has defined the concept of anemia as a hemoglobin value of less than 14 g / dl in men, 12 g / dl in women and 11 g / dl in pregnant women.
Among the numerous causes of anemia, iron deficiency is the most common. Not surprisingly, iron deficiency is probably the most widespread nutritional alteration in the world. Although the incidence of iron deficiency anemia is higher in developing countries, this form of anemia is also common in industrialized ones, especially in young children, adolescents and women of reproductive age.
Epidemiology
In the most developed countries, the incidence of iron deficiency is 3% among adult men, 20% among women and 50% among pregnant women. These percentages are destined to rise when some African countries are taken into consideration. or of Asia, where a reduced diet and an excessive loss of iron caused by the presence of intestinal parasites lead to iron deficiency anemia to affect more than 50% of the population.
Among adults it is mainly women who are affected, particularly during the childbearing age.
The trend in man is different, in which in fact two peaks of incidence are recognized: during adolescence and after 30 years of age.
However, the maximum incidence of anemia occurs between 6 and 20 months of life (both males and females) and in particular in premature babies. Finally, iron deficiency is more frequent in the poorer classes than in the upper middle classes (61% versus 39%).
Causes of anemia
A state of martial iron deficiency can be determined by:- inadequate intake;
- inadequate absorption;
- increased need;
- prolonged loss of iron.
Inadequate iron intake
Dietary deficiencies are a rare cause of anemia in industrialized countries that have abundant sources of supply (including meat), so that about two-thirds of dietary iron is in the form of readily absorbable heme groups. Therefore a decreased intake without there being absorption or need problems is a rare event.
The situation is quite different in developing countries, where food is less abundant and the diet, mainly vegetarian, contains inorganic iron (not linked to heme), which is not very absorbable.
However, despite the availability of iron, a diet can often prove inadequate in privileged societies when we find ourselves in the following circumstances:
- the elderly often follow very restricted diets, containing little meat for economic reasons or for the altered condition of their teeth.
- Adults on a strictly vegetarian diet because, even if fruit and vegetables contain moderate percentages of iron, it is equally true that there are nitrates, phosphates and fibers that tend to chelate (bind) iron and reduce its absorption.
- Poorer individuals, often from minorities, are most at risk.
- Infantile age is also at high risk of anemia, as the diet, consisting mainly of milk, contains very small amounts of iron.
- Alcoholics, as they tend to have a "poor quality diet."
- Children, especially during the first years of life, have a critical need for dietary iron to support the growth of muscle mass and to expand blood volume, and these quantities are often not compensated for by dietary intake.
Inadequate iron absorption
Reduced iron absorption is observed in conditions of intestinal steatorrhea (presence of unabsorbed fats in the faeces), in chronic diarrhea, in patients who have undergone surgery with large resections of the jejunum or ileum (by reduction of the absorbent surface) and in those with low stomach acid secretion (hypochlorhydria).
Furthermore, the resection of a portion of the stomach (gastrectomy) alters the absorption of iron by decreasing the secretion of hydrochloric acid and shortening the transit time of food from the stomach itself to the duodenum. Finally, they also alter the absorption of some foods present in the stomach. diet mentioned above.
Increased Need for Iron
Increased demand is a major possible cause of martial iron deficiency anemia. Growing children, adolescents, and menstruating and pregnant women have far greater iron requirements than adults. Particularly at risk are women with multiple and frequent pregnancies.
Prolonged loss of iron
Chronic blood loss is the most important cause of iron deficiency in the Western world.
The bleeding inside the tissues or in the body cavities can be followed by a complete healing with reuse of the iron, instead the external haemorrhage depletes the reserves. Such losses can occur in women of childbearing age (menstrual flow and pregnancy), in the gastrointestinal tract or elsewhere.
Gastrointestinal bleeding causes iron-free anemia especially in elderly patients and postmenopausal women. Among these, the most frequent lesions are hemorrhoids, hemorrhagic gastritis, gastric or duodenal ulcer, hiatal hernias, diverticula, especially those of the colon and that of Mekel (congenital diverticulum of the small intestine), colon and cancer of the of the stomach, chronic inflammatory bowel disease (ulcerative colitis and Crohn's disease), hookworm and pinworm diseases and the abuse of anti-inflammatory drugs such as aspirin.
Other sources of non-gastrointestinal bleeding can be found in the lungs, in the case of pneumonia or bronchopneumonia with hemoptysis (spitting of blood) or in idiomatic pulmonary hemosiderosis, in the kidney, in the case of chronic kidney inflammation, kidney tumors , of the urethra or bladder, which all lead to macroscopic or microscopic hematuria (presence of blood in the urine), at the female genital level, in the case of cancer of the uterus or menorrhagia (heavy menstrual bleeding), in states of chronic hemolysis (breakdown of red blood cells) due to the presence of heart valve prostheses, in blood donors, and finally in those suffering from paroxysmal nocturnal hemoglobinuria (a "haemolytic anemia).
Other articles on "Iron Deficiency Anemia"
- Anemia: symptoms, diagnosis, therapy
- Iron deficiency anemia - Drugs for the treatment of "iron deficiency anemia
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