Introduction to anemia and its epidemiology

Hello everyone I’m Susan Chang from school of nutrition and health science , Taipei Medical University in Taiwan. So it’s my honored to share this topic with you, so today we are going to talk about obesity and risk of iron deficiency anemia. So the learning objectives for today’s topic is that I’m going to cover an issue of what is Anemia? How it occurs? And what is Iron deficiency anemia? And also pathophysiology that associate with Iron metabolism that linked to obesity. So we are also going to discuss whether weight reduction alone can restore the normal iron status. So obesity and Iron deficiency are among the most common nutritional disorders in the world.

The association was first observed in the 1960s among obese children with decreased serum Iron being as frequent as 36% and 18% in obese males and females. Iron deficiency anemia occurs when there is not enough supply of iron for making red blood cell in the bone marrow. So obesity is not only restricted to Western countries but it is also a major problem in the Far East Asia. In Taiwan almost half of adult men and a third of adult women are overweight or obese. So this rate is much higher than in neighboring Asia countries. So globally, anemia also affects 1.6 billion people which corresponds to almost 25 percent of the population.

So in this global map of anemia and you can see the rate, dark rate color and this indicates that this countries has severe anemia. And that the prevalence rates of severe anemia is greater than 40 percent. However in developed countries like Western Europe, America, Canada or Japan, the prevalence rate of anemia is normally mild to normal. Mild means that anemia prevalence rate is between five percent to nineteen point nine percent. So the highest prevalence is in preschool age children and pregnant women. So almost one in two, a preschool age children and pregnant woman have a anemia. The lowest prevalence is in men. However the population group with the greatest number of individuals affected is non-pregnant woman.

So, in developed countries, and old people are also at high risk of anemia. For example, one third of Taiwanese elderly greater than 75 years of age have anemia. So, that means old people should also pay attention to Anemia as well So now you may have question what is Anemia and how it occurs? The major function of red blood cells, which are also called erythrocytes are to carry fresh oxygen throughout the body Anemia is a condition in which the size or number of red blood cell are not normal or red blood cell don’t contain enough hemoglobin to carry sufficient oxygen throughout the body.

So people with anemia may have an unusual red blood cell shape that look normal larger than normal or smaller than normal. Broadly speaking, there are two types of anemia nutritional and non nutritional anemia. So for Iron deficiency anemia, normally this is due to the insufficient iron intake in the diet. For pernicious anemia is the insufficient intake of vitamin B12. So for people who are underweight or malnutrition, normally they do not have enough energy or protein in their diet. In this case, they may also develop nutritional Anemia like children in Africa Another type of anemia is non nutritional.

So this can be due to the genetics or other underlying disease, like infection, toxin or if you have massive blood loss or if you have increased inflammation in your body. So these patients may develop Anemia but sometimes they also have iron accumulation in tissues or organs. Iron deficient anemia is characterized by microcytic which means small and hypochromic which means low pigment of red blood cell. So if you take your blood and look it on the microscope and you will find that normal red blood cell appears to be round shape and a little bit shiny.

But if you look at a blood from iron deficiency anemia patient and this red blood cell appears to be small and pale and this is due to the low hemoglobin concentration in the red blood cell.

So megaloblastic anemia has abnormal and immature red blood cell in the blood and this is due to the lack of vitamin B12 and folate in the diet pernicious anemia tend to occur in vegetarians or patients with part of stomach removed or undergo bariatric surgery for morbid obesity or patients. So vitamin B12 are normally are in meat products. So if you are vegetarians, that are normally the vitamin B12 is less amount in plant products. Stomach can also help to absorb vitamin B12 in the diet because stomach can secrete intrinsic factors Beta-thalassemia is the most common genetic disorder in Asia. So in Taiwan, the prevalence rate is around six to eight percent. And this is a due to a defect in beta-globin.

So this red blood cell will experience a premature death, and in this case, patients are more likely to develop Anemia. Sickle cell anemia is the most common genetic disorder in black people. Again this is due to a genetic mutation in beta-globin and so this will cause premature death of erythroid precursors in the bone marrow. So blood transfusion may require for severe anemia. Successful erythropoises requires nutrients hormone and growth factors. Kidney can secrete an important hormone called erythropoietin. EPO stimulates red blood cell synthesis in the bone marrow so if you have a chronic kidney problems like dialysis patients and they have decreased EPO level, in this case, they have a high risk of developing Anemia.

Another factor that may affect red blood cell synthesis is the genetic factors. So genetic factors can affect globin synthesis. So overall, erythropoiesis not only require nutrients but also you have to take into account like genetic factors and also the organs like the kidney function. So if your doctor tells you that you have anemia, then you may ask your doctor “Is this due to the iron deficiency? Or it’s due to genetic factors? Or is due to my kidney problem ? So in this case it may helps you to overcome the anemia problem.