Table 2.

Benchmark dose results (mg/L urinary fluoride) for a BMR of 1 IQ point obtained from the MIREC study and the two cognitive assessments from the ELEMENT study as well as the joint results. Two dose-response models are used, a linear and one with the squared exposure variable. For both models, sex-specific and joint benchmark results are provided. The fit of the regression models were compared by twice the log-likelihood [−2 logi] where lower values indicate a better fit.

Study		MIREC (n=512)		ELEMENT IQ (n=211)		ELEMENT GCI (n=287)		MIREC and ELEMENT IQ (n=723)			MIREC and ELEMENT GCI (n=799)
Model	Sex	BMD	BMDL	BMD	BMDL	BMD	BMDL	BMD	BMDL	−2logL	BMD	BMDL	−2logL
Linear	Both	0.483	0.208	0.200	0.122	0.159	0.099	0.303	0.186	5541.9	0.286	0.175	6263.1
Linear	Boys	0.218	0.127	0.275	0.130	0.148	0.084	0.237	0.148	5536.3	0.192	0.125	6258.0
Linear	Girls	∞	0.515	0.160	0.091	0.169	0.087	0.691	0.218	5536.3	1.372	0.247	6258.0
Squared	Both	1.019	0.661	0.614	0.496	0.611	0.467	0.756	0.606	5540.5	0.809	0.619	6264.5
Squared	Boys	0.716	0.537	0.684	0.496	0.581	0.435	0.703	0.558	5535.5	0.666	0.533	6259.8
Squared	Girls	∞	1.158	0.576	0.449	0.642	0.434	0.921	0.609	5535.5	6.436	0.729	6259.8