SECONDARY POLYCYTHEMIA IN ADOLESCENTS AT HIGH ALTITUDE.

Abstract

Abstract Significant changes in the production of red Mood cells occur after puberty. The pattern of these changes by age and sex has been well described in populations living near sea level. Since chronic hypoxia might well modify this hematologic pattern the normal adolescents of a population residing at a high altitude were studied. Samples of venous blood were obtained from 355 boys and girls ranging in age from 10 to 18 years and living at an altitude of 10,200 feet in Leadville, Colorado. Whole blood hematocrit, hemoglobin concentration, and red blood cell count were determined. Serum from clotted blood was analyzed for iron content unsaturated iron-binding capacity, and bilirubin concentration. The effects of chronic hypoxia were clearly manifest in girls. Throughout the age range of 10 to 18 years, mean values for hemoglobin hematocrit and R.B.C. count were higher than at comparable ages at sea level. However, there was little or no tendency of these parameters to increase with age. Among the boys the effects of high altitude were also obvious, in that all 3 parameters were higher than at comparable ages at low altitudes. Prior to puberty, boys and girls had similar blood values. However, in boys puberty apparently provided an added stimulus to red cell production. From 14 to 18 years of age, there was a progressive and significant increase in all 3 parameters when compared with the data from girls. There was no evidence of iron deficiency in either sex. These data indicate that chronic hypoxia produces a significant erythrocytosis throughout adolescence in both boys and girls living at an altitude of 10,200 feet.