Curvilinear relationship between blood lead level and reaction time : Differential association with blood lead fractions derived from exogenous and endogenous sources.
Prior studies demonstrate an inconsistent relationship between occupational inorganic lead exposure and simple reaction time (SRT) performance.
In this study, we administered a computerized SRT test to 78 currently employed lead smelter workers and then investigated the relationship between different measures of blood lead and components of SRT performance.
The measures of blood lead included current blood lead (PbB) and mathematically derived blood lead fractions from the environment (PbB-env) and from bone (PbB-bn).
Measures of SRT performance, obtained from 44 trials with interstimulus intervals (ISIs) ranging from I to 10 seconds, included median SRT (SRT-md), mean SRT for ISIs between 1 and 5 seconds (SRT-1-5), and mean SRT for ISIs between 6 and 10 seconds (SRT-6-10).
Multiple regression analysis after adjustment for age and education revealed a curvilinear relationship between PbB and SRT-md.
As PbB increased from 0 to 30 mug dl-1, SRT-md decreased, and only with PbB levels above 30 mug d-1 did SRT-md increase.
PbB terms accounted for 13. 7% of the variance in this SRT measure (P<0.01).
The longer ISI variable, SAT-6-10, was found to be more strongly related to PbB, to have lesser variability across ISIs, and to be unrelated to age.
Additional multiple regression analysis to examine the relationship between components of SRT and the PbB fractions, PbB-env and PbB-bn, showed only PbB-env to account for significant variance in SRT-md, (14.4%, P<0.01), SRT-1-5 (9. (...)
Mots-clés Pascal : Plomb, Métal lourd, Taux, Sang, Homme, Fonderie, Temps réaction, Comportement, Exposition professionnelle, Médecine travail, Relation concentration activité, Toxicité
Mots-clés Pascal anglais : Lead, Heavy metal, Rate, Blood, Human, Foundry, Reaction time, Behavior, Occupational exposure, Occupational medicine, Activity concentration relation, Toxicity
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 97-0340429
Code Inist : 002B03L05. Création : 12/09/1997.