Blood lead concentrations in hereditary hemochromatosis

We postulated that patients with hereditary hemochromatosis (HH) absorb increased quantities of lead, as do iron-deficient subjects. To test this hypothesis, whole blood lead concentration ([blood Pb]) was quantified by atomic absorption spectrometry in HH homozygotes (n = 44), obligate heterozygotes (n = 19), normal control subjects (n = 33), and abnormal controls with transfusion-induced iron overload (n = 8). HH homozygotes had higher [blood Pb] than did normal control subjects (5.6 ± 0.6μg/dl vs 3.6 ± 0.5 μg/dl; p < 0.005); significantly increased mean [blood Pb] was observed in both male and female homozygotes. In heterozygotes, the mean [blood Pb](4.1 ± 0.5 μ-g/dl) was intermediate between that of homozygotes and normal control subjects. The mean [blood Pb] of subjects with transfusion-induced iron overload (2.2 ± 0.6 μg/dl) did not differ significantly from that of normal controls. The findings in homozygotes could not be related to age, serum ferritin concentration, presence or absence of iron loading, or the extent of therapeutic phlebotomy. Lead exposure in all of our subjects was due primarily to ambient sources. Analysis of our data, when using a mathematical biokinetic model of human lead metabolism, suggests that the most likely explanation for our findings is that homozygotes (and, to a lesser extent, heterozygotes) absorb increased quantities of lead, a conclusion that corresponds to the increased absorption of iron and cobalt previously documented in homozygotes.