The Influence of Age upon Serum Iron in Normal Subjects

This investigation was carried out in order to explore the possibility of a correlation between the process of ageing and the concentration of iron in the serum.It also provides additional information on the reliability of the potassium ferri- cyanide method for the determination of serum iron.Vahlquist (1941) studied the influence of age upon serum iron concentration during the first 15 years of life.Within 24 hours of birth, serum iron falls from its neonatal value of 160 jug.% to a level of 50 jug.%.A secondary rise to 125 1tg.% during the next two weeks is succeeded by a gradual fall so that the average value in the age group 6 months to 2 years is 60 jug.%.After the second year the concentration of iron in the serum increases progressively to an average of 100 jug.% at 7 years, 110 ,ug.% at 11 years, and 120 jug.% at 15 years.Eckerstr6m (1944a, b) determined serum iron in 100 subjects over 70 years of age and found that not only was the sex difference in serum iron still apparent at these ages, but also that serum iron was significantly lower than in healthy subjects under 30 years of age. Material and MethodsThe material was composed mainly of blood donors, namely healthy individuals between the ages of 17 and 65 years of age, who gave no history of recent illness, whose physical condition was good, and whose haemoglobin was 85% or more, as estimated by the copper sulphate method of Philips, Van Slyke, Dole, Emerson, Hamilton, and Archibald (1945).The age groups 10 to 17 years and 65 to 80 years were composed respectively of children with minor injuries and of adult volunteers whose health standard conformed to the above criteria.Females who were men- struating were rejected.All specimens were withdrawn in the afternoon.In the case of blood donors, serum iron was determined on samples removed immediately after withdrawal of 540 ml. of blood.This procedure was desirable, since it minimized interference with the regime of the transfusion service, but was adopted only after it was shown that the iron content of the serum was not influenced significantly by the immediately preceding donation of blood.This observation agrees with that of Heilmeyer and Plotner (1937), who noted that the withdrawal of 500 to 800 ml. of blood from normal persons did not reduce serum iron until-at least six hours later.Likewise, Brochner-Mortensen (1943), who studied two cases of acute gastro-intestinal haemorrhage from the onset, obtained normal values for serum iron during the first 24 hours.