Table 3. Association between brain iron composite, plaque and NFTs, with different domains of cognition in subjects who had AD neuropathology with or without dementia at time of death.

Data were obtained from mixed-effects models of cognitive performance (e.g. Global Cognition) that included linear and quadratic terms for the following covariates, interacted with time: age, sex, APOE-ε4, years of education, plaque counts, tangle counts, presence of Lewy bodies, presence of gross infarcts and, in separate models, iron levels in the brain regions listed. Data are differences in model fit (change in log likelihood: ΔLL) and associated levels of significance determined by χ² analysis between models with and without each individual variable (both linear and quadratic terms).

		Global Cognition			Working Memory			Semantic Memory			Perceptual Speed			Perceptual Organization			Episodic Memory
Dementia	Variable	ΔLL	χ2	P	ΔLL	χ2	P	ΔLL	χ2	P	ΔLL	χ2	P	ΔLL	χ2	P	ΔLL	χ2	P
Yes	Aβ plaques	−1.8	3.5	0.172	−1.2	2.3	0.310	−3.1	6.3	0.043	0.0	0.0	0.996	−0.8	1.7	0.429	−2.3	4.6	0.101
	NFT	−20.6	41.2	<0.001	−2.1	4.2	0.120	−21.7	43.4	<0.001	−2.8	5.5	0.062	−0.5	0.9	0.634	−11.2	22.3	<0.001
	Iron composite	−9.3	18.6	<0.001	−5.1	10.2	0.006	−3.2	6.5	0.039	−13.1	26.1	<0.001	−2.4	4.9	0.087	−0.7	1.3	0.518
	Inferior temporal iron	−4.4	8.9	0.012	−3.3	6.5	0.039	−3.3	6.7	0.035	−9.9	19.8	<0.001	−0.1	0.3	0.866	−0.1	0.1	0.945
	Mid Frontal iron	−4.9	9.9	0.007	−2.9	5.8	0.055	−2.2	4.4	0.111	−4.3	8.5	0.014	−0.9	1.7	0.417	−0.9	1.9	0.388
	Anterior cingulate iron	−5.6	11.2	0.004	−1.7	3.4	0.181	−4.7	9.4	0.009	−8.7	17.4	<0.001	−1.1	2.1	0.348	−1.9	3.8	0.149
	Cerebellum iron	−7.1	14.1	0.001	−5.0	10.0	0.007	−2.9	5.8	0.054	−12.2	24.4	<0.001	−2.9	5.8	0.056	−3.3	6.7	0.036
No	Aβ plaques	−3.2	6.5	0.039	−2.5	4.9	0.084	−0.5	1.1	0.591	−3.9	7.8	0.020	−3.1	6.1	0.047	−1.2	2.3	0.312
	NFT	−17.0	34.0	<0.001	−3.5	7.0	0.030	−11.7	23.4	<0.001	−9.1	18.2	<0.001	−4.3	8.7	0.013	−23.6	47.3	<0.001
	Iron composite	−5.9	11.9	0.003	−5.2	10.3	0.006	−2.3	4.7	0.097	−0.8	1.6	0.448	−2.1	4.2	0.122	−3.6	7.1	0.029
	Inferior temporal iron	−3.4	6.8	0.033	−2.3	4.7	0.098	−3.3	6.6	0.037	−0.3	0.5	0.775	−0.1	0.3	0.863	−2.6	5.2	0.075
	Mid Frontal iron	−12.9	25.9	<0.001	−5.6	11.2	0.004	−7.7	15.5	<0.001	−1.4	2.8	0.244	−2.5	5.0	0.081	−7.6	15.3	<0.001
	Anterior cingulate iron	−0.8	1.6	0.459	−1.5	3.1	0.213	−0.6	1.1	0.565	−0.4	0.9	0.648	−0.4	0.9	0.647	−0.1	0.2	0.899
	Cerebellum iron	−0.8	1.7	0.435	−1.5	3.0	0.223	−0.4	0.8	0.674	−0.5	0.9	0.636	−0.9	1.7	0.421	−1.3	2.6	0.274

Bold values represent P<0.05.