OCCUPATIONAL LEAD-EXPOSURE AND SCREENING OF GLUCOSE-6-PHOSPHATE-DEHYDROGENASE POLYMORPHISM - USEFUL PREVENTION OR NONVOLUNTARY DISCRIMINATION

Objective: To discuss regulatory guidelines excluding subjects with er ythrocyte glucose-6-phosphate dehydrogenase (G6PD) deficiency from lea d-exposed jobs in the light of epidemiology findings on the mortality of these subjects. Methods: Two mortality follow-up studies were condu cted. The first comprised 1979 male subjects newly identified as G6PD- deficient during a 1981 screening of the G6PD polymorphism among the g eneral population in Sardinia, Italy. The second comprised 1080 male w orkers employed in maintenance and production departments of a lead sm elting plant, who were divided into two subcohorts by erythrocyte G6PD phenotype. Results: As compared with the general male population, G6P D-deficient subjects had significantly fewer deaths than expected from ischemic heart disease (standardized mortality ratio (SMR) = 28: 95% CI 10-62), cerebrovascular diseases (SMR = 22; 95% CI 6-55), and liver cirrhosis (SMR = 12; 95% CI 0-66). Among lead smelters the standardiz ed mortality rates from cardiovascular diseases and all cancers observ ed among the G6PD-deficient subcohort were lower than those seen among subjects with the wild-type G6PD. No death from disease of the blood and hematopoietic system was observed among G6PD-deficient subjects in these two follow-up studies. Conclusions: These studies did not provi de evidence of hypersensitivity to lead hematotoxicity among G6PD-defi cient individuals at exposure levels within the current standards. Pro vided that workplace exposure complies with current standards, the hyp othetical benefit of excluding G6PD-deficient individuals from lead-ex posed jobs should be weighted against the loss of personal abilities a nd the economic damage in a social environment with diffuse unemployme nt.