Table 2

 Associations of neurobehavioural tests with various lead exposure/dose metrics. From a cross-sectional study of 535 former lead workers (adapted from Links et al25)

Neurobehavioural measure*Current PbB†Current PbTPeak PbTAUC dose metric
β‡p Value§βp Valueβp Valueβp Value
*Selection from a battery of 16 tests. All tests scored so that a worsening of performance with increasing exposure is indicated by a negative sign.
†Dose metrics: current PbB, current blood lead concentration, at time of testing; current PbT, current tibial lead concentration, at time of testing; peak PbT, highest estimated tibial lead concentration, back-extrapolated using a one-compartment model and an average clearance half time of 27 years; AUC dose metric, area under the time-concentration curve for tibial lead.
‡Regression coefficient, adjusted for age, education and baseline score, and standardised so that all β represent change in score per standard deviation change in exposure/dose metric.
§p Value testing H0: β = 0. Large coefficients relative to their standard errors indicated in bold italics.
Wechsler block design0.1610.23−0.0580.72−0.2230.18−0.2130.22
Wechsler symbol digit−0.1870.14−0.1330.32−0.0380.790.0580.68
Symbol digit−0.0120.91−0.0990.32−0.206 0.05 −0.225 0.04
Serial digit learning−0.1600.23−0.0200.90−0.1040.52−0.1490.37
Rey figure copy−0.0010.99−0.0300.74−0.1380.14 −0.170 0.08
Rey figure recall −0.174 0.05 −0.0770.39−0.174 0.07 −0.196 0.04
Rey auditory learning, immediate recall0.0490.77−0.2550.15−0.571 <0.001 −0.671 <0.001
Rey auditory learning, delayed recall−0.0550.32 −0.128 0.02 −0.149 0.01 −0.134 0.02