engleski

Serum selenium in relation to biomarkers of lead in men

There is conclusive evidence from numerous experimental animal studies that selenium (Se) can reduce the toxicity of several metals, including lead (Pb). On the other hand, very few data are available on the possible influence of Pb exposure on Se status in humans. Serum selenium (S-Se), blood lead (B-Pb) and activity of delta-aminolevulenic acid dehydratase (ALAD) were measured in 93 male subjects occupationally exposed to Pb and 85 male subjects not occupationally exposed to Pb, living in the urban area of Zagreb. None of the subjects had ever been occupationally exposed to other metals, or had hobbies involving risk of metal exposure, or used any medication that could influence metal metabolism. All subjects gave their informed consent prior to inclusion in the study. The S-Se and B-Pb measurements were performed by using electrothermal AAS and the accuracy controlled by regular participation in the Trace Elements External Quality Assessment Scheme for S-Se (Guildford, UK) and the National External Quality Assessment Scheme for B-Pb (Birmingham, UK). Activity of ALAD was measured by the European standardized method (A. Berlin and K.H. Schaller, 1974). There was no significant difference between the groups in age (36.3 ą 8.8 and 37.9 ą 7.8 years, respectively), smoking habits (14.8 ą 13.6 and 10.9 ą 13.4 cigarettes/ day, respectively), or alcohol consumption (7.4 ą 9.8 and 8.5 ą 8.7 units of alcohol/ week, respectively). Compared to the reference subjects, Pb workers had significantly increased B-Pb (375 ą121 and 75 ą 27 ľg/L, respectively; P<0.0001), lowered ALAD (22.4 ą 9.8 and 49.8 ą 8.8 European Units, respectively; P<0.0001), and lowered S-Se (60.7 ą 10.3 and 66.9 ą 12.5 ľg/L, respectively; P<0.005). Highly significant relationships were found between S-Se with respect to B-Pb (S-Se = -7.62 log B-Pb + 80.6; r = -0.247, P<0.001) and ALAD (S-Se = 0.19 ALAD + 56.9; r = 0.269, P<0.0005). The relatively better correlation of S-Se with ALAD compared to B-Pb may be ascribed to the fact that B-Pb mainly reflects current or recent Pb exposure level, while ALAD better reflects long-term cumulative Pb exposure of an individual.

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