TABLE 5.

Parameters and effect sizes for the models for the mediating effects of changes in brain activity on the relation between changes in measures of blood iron and measures of cognitive performance¹

Mediators							Primary outcome							Effect sizes
Variable	Pred	F	Int	β	t	R2	Variable	Pred	F	Int	β	t	R2	Total	Indirect	Ratio
Model for attentional capture
Capt α	SF	9.99&	0.31	0.40	4.81&	0.31	Capt RT	SF	8.08&	−0.15	0.48	2.69%	0.42	0.61	0.48	0.79
	Hb			0.24	2.13*			Hb			0.22	2.14*
Capt N1	SF	6.45%	0.07	0.22	2.23*	0.22		Capt α			0.27	2.05*
	Hb			0.41	2.72%			Capt N1			0.17	1.85+
Model for attentional selection
Seln α	SF	11.01&	−0.19	0.37	2.99%	0.31	Seln RT	SF	8.14&	−0.07	0.36	2.24*	0.41	0.57	0.36	0.63
	Hb			0.24	2.48*			Hb			0.19	1.92+
Seln N1	SF	8.27&	0.18	0.34	2.29*	0.25		Seln α			0.39	2.41*
	Hb			0.28	2.46*			Seln N1			0.19	2.06*
Model for ME, new items
ME new α	SF	7.84%	0.00	0.34	2.09*	0.25	ME new	SF	4.13%	0.00	0.15	1.81*	0.34	0.36	0.15	0.42
	Hb			0.32	2.48*			Hb			0.14	1.93*
ME new γ	SF	8.60&	−0.05	0.76	4.07&	0.26		ME new α			0.10	1.72+
	Hb			0.14	2.35*			ME new γ			0.15	2.09*
ME new N1	SF	6.25%	0.00	0.34	1.86+	0.21		ME new N1			0.18	1.82*
	Hb
Model for ME, old items
ME old α	SF	14.86&	0.05	0.93	5.45&	0.37	ME old	SF	8.98&	0.13	0.31	2.66*	0.49	0.36	0.21	0.58
	Hb			0.23	1.72+			Hb			0.24	3.05%
ME old γ	SF	8.60&	−0.05	0.76	4.07&	0.26		ME old α			0.11	1.81+
	Hb			0.17	2.05+			ME old γ			0.15	2.09*
ME old N1	SF	14.40&	0.20	0.24	1.73+	0.37		ME old N1			0.18	2.11*
	Hb			0.69	4.55&

¹In all cases, change in Hb was used as a covariate. Capt, attentional capture; Int, intercept; ME, memory efficiency; Pred, predictor; Seln, attentional selection.

⁺0.05 ≤ P < 0.10, *P < 0.05, ^%P < 0.01, ^&P < 0.001.