Polycythemia (also known as polycythaemia or polyglobulia) is a disease state in which the proportion of blood volume that is occupied by red blood cells increases. Blood volume proportions can be measured as hematocrit.It can be due to an increase in the number of red blood cells (absolute polycythemia) or to a decrease in the volume of plasma (relative polycythemia).lood volume proportions can be measured as hematocrit. It can be due to an increase in the number of red blood cells (absolute polycythemia) or to a decrease in the volume of plasma (relative polycythemia).
1 Some 20% of adolescents with major depression develop bipolar disorder within five years of the onset of depression. ( 2 Birmaher, B., Childhood and Adolescent Depression: A Review of the Past 10 Years.. 3  Part I, 1995).
Rates of obesity have increased dramatically in recent decades for Americans of all ages according to the Centers for Disease Control and Prevention (CDC). The percent of children and teens who are overweight is also growing. Among teens ages 12 to 19, 18 percent are obese, according to the 2008 data. This is triple the proportion of overweight youth in 1980. Furthermore, data suggests that 30 percent of children and teens ages 6 to 19 are overweight.