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Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Anemia


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Overview

Anemia is defined as an abnormally low number of red blood cells (RBCs), an abnormally low amount of oxygen-carrying protein (hemoglobin) inside each RBC, or an abnormally low measure of red cell mass compared to the volume of plasma (hematocrit). In all three of these deficiencies, the oxygen-carrying capacity of the blood is decreased, resulting in less oxygen supply to body tissues (hypoxia).

Anemia is not a disease but rather a sign of many conditions or diseases. Causes are grouped into three categories: blood loss, RBC destruction (hemolysis), and impaired or decreased RBC production.

Blood loss can be sudden and acute such as with a traumatic penetrating injury, ruptured aneurysm, or major surgery. Slow and chronic blood loss can occur in gastrointestinal bleeding or in parasitic diseases such as uncinariasis. Blood coagulation disorders such as hemophilia also may cause excessive bleeding resulting in anemia. Blood loss due to heavy and prolonged menstrual bleeding (menorrhagia) or frequent menstrual bleeding (polymenorrhea) is another cause of this type of anemia.

RBCs may be destroyed or removed from circulation faster than they can be replaced by new RBCs produced in the bone marrow. This occurs when there are defects within the RBC (e.g., in sickle cell disease, hereditary spherocytosis), when antibodies attack and destroy otherwise healthy RBCs (e.g., in a transfusion reaction, autoimmune hemolytic anemia, systemic lupus erythematosus), when there are inclusion bodies within the RBC such as malarial parasites, or as a result of viral diseases that affect liver function (e.g., infectious mononucleosis, hepatitis). A general term for this type of anemia is hemolytic anemia, referring to hemolysis of RBCs at a much higher rate than normal regardless of the underlying cause.

Impaired RBC production is a broad category that includes conditions and diseases affecting either the number of RBCs produced or how they are produced. RBCs are produced in the bone marrow in response to the action of the hormone erythropoietin (EPO), which is made in the kidney. Kidney disease, cancer, chronic infection, or inflammation can decrease the production of EPO or interfere with its activity. Without active EPO, the bone marrow does not produce an adequate number of RBCs.

Problems inside the bone marrow also interfere with blood cell production. Sometimes the marrow stops producing RBCs as in aplastic anemia, a condition with severely decreased production of RBCs and other blood cells (white blood cells [WBCs] and platelets) due to defective regeneration within the bone marrow. This can occur in response to exposure to a toxic drug or chemical, or infection caused by certain viruses. Often, however, there is no known etiology for the condition (idiopathic aplastic anemia). A decrease in RBC production (hypoplasia) is found in malnutrition, particularly in the eating disorder anorexia nervosa. Myelodysplasia refers to a condition in which early RBCs (reticulocytes) do not develop properly in the bone marrow and die before being released into the circulatory system.

RBC production is impaired when the required synthesis of deoxyribonucleic acid (DNA) within the cell is defective, resulting in megaloblastic anemia. Megaloblastic anemia is most often caused by a deficiency of either folate or vitamin B12 (pernicious anemia). Some cases of megaloblastic or aplastic anemia are caused by administration of certain chemotherapeutic cancer drugs or exposure to certain chemical solvents such as benzene.

A problem with the synthesis of hemoglobin also can interfere with normal RBC production within the marrow. Because hemoglobin is an iron-containing protein, a deficiency of iron creates a deficiency of functional hemoglobin. Iron deficiency anemia may result from an insufficient amount of iron in the diet or malabsorption of iron from the gastrointestinal tract. More often, however, it occurs because either blood loss or increased demand has triggered the marrow to increase production in an effort to replace lost RBCs beyond the supply of iron available.

Chronic disease also can cause iron deficiency anemia if the disease interferes with the normal integration of iron into the RBC. Sideroblastic anemia is a type of anemia in which iron cannot be properly utilized.

In other cases, anemia can result when the RBC membrane that surrounds hemoglobin is abnormal, when certain glycolytic enzymes reduce the lifespan of RBCs, or when the chemical composition of hemoglobin itself is abnormal. Thalassemia is an inherited blood disorder with anemia that involves abnormal production of the proteins (polypeptide chains of globin) needed to make normal hemoglobin.

Some forms of blood disorders with anemia are inherited (e.g., hereditary spherocytosis, thalassemia, sickle cell disease), as are most blood coagulation disorders that involve deficiencies of specific coagulation factors needed to form clots when the skin is penetrated and bleeding occurs. Coagulation disorders are not forms of anemia but often result in extended bleeding that leads to anemia.

Incidence and Prevalence: Iron deficiency anemia is the most common type of anemia. About 20% of children will have anemia at some point in their childhood (Janus). There are 2.4 million children with iron deficiency, and 490,000 with iron deficiency anemia (Brotanek). The frequency of iron deficiency anemia varies by age, with 14% of children aged 1 to 2 years, 4% aged 3 to 5 years, and 9% of females aged 12 to 49 years old affected (CDC). Hispanic children are twice as likely to be iron deficient as white children (Brotanek). High anemia rates (between 18% to 39%) have been reported for blacks.

Among the elderly the prevalence of anemia is 12.6% in women and 14.1% in men. Anemia and mild anemia dramatically increases with age: from 4.9 per 1000 person-years among 65 to 69 year olds to 72.4 per 1000 person-years among 80 to 84 year olds (Tettamanti).

Source: Medical Disability Advisor