Anemia

Anemia is a <a href="/facts/Blood_disorder/QB4CeNEF">blood disorder</a> in which the <a href="/facts/Blood/03zEulkj">blood</a> has a reduced ability to carry <a href="/facts/Oxygen/acyn6o8r">oxygen</a>. This can be due to a lower than normal number of <a href="/facts/Red_blood_cell/Kggpq8Jh">red blood cells</a>, a reduction in the amount of <a href="/facts/Hemoglobin/RsD1MzYA">hemoglobin</a> available for oxygen transport, or abnormalities in haemoglobin (also spelt haemoglobin <a href="/facts/British_English/ymJR5Rnd">British English</a>) that impair its function. The name is derived from <a href="/facts/Ancient_Greek_language/LIK7NlUh">Ancient Greek</a> ἀν- (an-) 'not' and αἷμα (haima) 'blood'.
When anemia comes on slowly, the symptoms are often vague, such as <a href="/facts/Fatigue/C2oo4Hvg">tiredness</a>, <a href="/facts/Weakness/U9wAgeLn">weakness</a>, <a href="/facts/Shortness_of_breath/1jBfFzxU">shortness of breath</a>, <a href="/facts/Headache/mdmmC9DP">headaches</a>, and a <a href="/facts/Exercise_intolerance/IPWLfqs6">reduced ability to exercise</a>. When anemia is acute, symptoms may include <a href="/facts/Confusion/Pcvw6deb">confusion</a>, <a href="/facts/Lightheadedness/Gcuruugy">feeling like one is going to pass out</a>, <a href="/facts/Syncope_(medicine)/AqU1whYh">loss of consciousness</a>, and <a href="/facts/Polydipsia/aYTYCDDb">increased thirst</a>. Anemia must be significant before a person becomes noticeably <a href="/facts/Pallor/bHpLxohY">pale</a>. Additional symptoms may occur depending on the underlying cause. Anemia can be temporary or long term and can range from mild to severe.
Anemia can be caused by <a href="/facts/Blood_loss/CGyFMU0F">blood loss</a>, decreased red blood cell production, and increased <a href="/facts/Hemolysis/1WpVYHkP">red blood cell breakdown</a>. Causes of blood loss include <a href="/facts/Gastrointestinal_bleeding/ynYL5PXm">bleeding due to inflammation of the stomach or intestines</a>, bleeding from <a href="/facts/Surgery/fG8tWf5Y">surgery</a>, serious <a href="/facts/Injury/PJ7CbnMQ">injury</a>, or <a href="/facts/Blood_donation/PIvGgUSW">blood donation</a>. Causes of decreased production include <a href="/facts/Iron_deficiency/wK3f3IuR">iron deficiency</a>, <a href="/facts/Folate_deficiency/aqffhQzn">folate deficiency</a>, <a href="/facts/Vitamin_B12_deficiency/WeChf6H3">vitamin B12 deficiency</a>, <a href="/facts/Thalassemia/NF7GIJsJ">thalassemia</a> and a number of <a href="/facts/Neoplasms_of_the_bone_marrow/tzyyShka">bone marrow tumors</a>. Causes of increased breakdown include <a href="/facts/Genetic_disorder/hFqt2NLn">genetic disorders</a> such as <a href="/facts/Sickle_cell_anemia/93LT7ATq">sickle cell anemia</a>, infections such as <a href="/facts/Malaria/rN3g58CX">malaria</a>, and certain <a href="/facts/Autoimmune_disease/sojBeQ7t">autoimmune diseases</a> like <a href="/facts/Autoimmune_hemolytic_anemia/cQeKSWIK">autoimmune hemolytic anemia</a>. 
Anemia can also be classified based on the <a href="/facts/Mean_corpuscular_volume/jou11aso">size of the red blood cells</a> and <a href="/facts/Mean_corpuscular_hemoglobin/9I18aAPe">amount of hemoglobin in each cell</a>. If the cells are small, it is called <a href="/facts/Microcytic_anemia/mwjbD90U">microcytic anemia</a>; if they are large, it is called <a href="/facts/Macrocytic_anemia/EyUTHKno">macrocytic anemia</a>; and if they are normal sized, it is called <a href="/facts/Normocytic_anemia/Gn7zqyRI">normocytic anemia</a>. The diagnosis of anemia in men is based on a hemoglobin of less than 130 to 140 g/L (13 to 14 g/dL); in women, it is less than 120 to 130 g/L (12 to 13 g/dL). Further testing is then required to determine the cause.
Treatment depends on the specific cause. Certain groups of individuals, such as pregnant women, can benefit from the use of <a href="/facts/Iron_pill/okvPXPWP">iron pills</a> for prevention. <a href="/facts/Dietary_supplement/SHXNNxaS">Dietary supplementation</a>, without determining the specific cause, is not recommended. The use of <a href="/facts/Blood_transfusion/fb0Mk6Dx">blood transfusions</a> is typically based on a person's signs and symptoms. In those without symptoms, they are not recommended unless hemoglobin levels are less than 60 to 80 g/L (6 to 8 g/dL). These recommendations may also apply to some people with acute bleeding. <a href="/facts/Erythropoiesis-stimulating_agent/2tgXMKrv">Erythropoiesis-stimulating agents</a> are only recommended in those with severe anemia.

Anemia is the most common blood disorder, affecting about a fifth to a third of the global population. <a href="/facts/Iron-deficiency_anemia/LK17js79">Iron-deficiency anemia</a> is the most common cause of anemia worldwide, and affects nearly one billion people. In 2013, anemia due to iron deficiency resulted in about 183,000 deaths – down from 213,000 deaths in 1990. This condition is most prevalent in children with also an above average prevalence in elderly and women of reproductive age (especially during pregnancy). Anemia is one of the six <a href="/facts/WHO/0SrenJ5L">WHO</a> global nutrition targets for 2025 and for diet-related global targets endorsed by <a href="/facts/World_Health_Assembly/j4fbxHMc">World Health Assembly</a> in 2012 and 2013. Efforts to reach global targets contribute to reaching <a href="/facts/Sustainable_Development_Goals/b7lVYvFN">Sustainable Development Goals</a> (SDGs), with anemia as one of the targets in <a href="/facts/SDG_2/mV584m7j">SDG 2</a> for achieving zero world hunger.

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Anemia