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 PbT		Peak PbT		AUC dose metric
Neurobehavioural measure*	β‡	p Value§	β	p Value	β	p Value	β	p 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 design	0.161	0.23	−0.058	0.72	−0.223	0.18	−0.213	0.22
Wechsler symbol digit	−0.187	0.14	−0.133	0.32	−0.038	0.79	0.058	0.68
Symbol digit	−0.012	0.91	−0.099	0.32	−0.206	*0.05*	*−0.225*	*0.04*
Serial digit learning	−0.160	0.23	−0.020	0.90	−0.104	0.52	−0.149	0.37
Rey figure copy	−0.001	0.99	−0.030	0.74	−0.138	0.14	*−0.170*	*0.08*
Rey figure recall	*−0.174*	*0.05*	−0.077	0.39	−0.174	*0.07*	*−0.196*	*0.04*
Rey auditory learning, immediate recall	0.049	0.77	−0.255	0.15	−0.571	*<0.001*	*−0.671*	*<0.001*
Rey auditory learning, delayed recall	−0.055	0.32	*−0.128*	*0.02*	−0.149	*0.01*	*−0.134*	*0.02*