Chronic industrial exposure to lead in 63 subjects. I. Clinical and erythrokinetic findings.

Clinical, biochemical, haematological and erythrokinetic studies were performed on 63 adult males with prolonged lead exposure. Their most common symptoms and findings were abdominal pain (62%), gingival lead lines (48%), headache and/or dizziness (33%), muscle cramps (32%), anaemia (19%), and fatigue (18%). Colicky abdominal pain (27%) and gingival lead lines correlated with urinary lead excretion. Anaemia was mild, but more frequent in the subjects with the greatest urinary lead excretion. Other associated findings were: higher reticulocyte counts and more basophilic stippling of the RBCs, more sideroblasts and greater erythroid hyperplasia of the bone marrow, more reduction in 51Cr-tagged RBC survival time, smaller RBC mass, a more rapid plasma iron clearance, a greater plasma iron turnover and greater utilization of 59Fe in subjects with urinary lead excretion of greater than 100 microng/day in comparison with the remainder and normal controls. These findings suggest that minimal chronic exposure to lead causes an increased haemolysis with resulting increased production of erythrocytes.