Transferrin types, iron-binding capacity and body iron stores.

Increased body iron stores and transferrin (TF) variants have been found to be associated with adverse health effects believed to be caused by oxygen free radicals. Previous attempts to establish a relationship between TF types, serum TF concentrations and iron-binding have been inconclusive. We have studied serum iron, total iron-binding capacity (TIBC), TF saturation and serum ferritin in relation to genetic TF types in a population sample (691 females and 639 males) from northern Sweden in an attempt to elucidate whether individuals with TF variants associated with adverse somatic and reproductive effects (TFC2 and C3) have increased body iron stores. As expected there was a highly significant sex difference, males manifesting increased body iron stores viz. increased levels of serum iron, TF saturation and serum ferritin, and a lower TIBC. There was no consistent and statistically significant association between the TFC2 variant and the parameters that indicate iron binding and storage. Thus the associations between TFC2 and somatic and reproductive damage appear to be independent of iron binding and body iron stores. TIBC (and TF levels) showed significant differences between TF types in females (p = 0.0015) but not in males. In females the TFC3 variant was associated with a significantly lower (p = 0.002) TIBC value. This decreased TIBC value was, however, not accompanied by an increased ferritin value, thus there was no unequivocal evidence for an association between TFC3 and increased body iron stores.