Table 2.

Summary of the nonlinear mixed effects model of mean Fractional Anisotropy (FA) with NWI, NWI × NWI and the WMH load as main fixed factors, including NWI by WMH load and NWI × NWI by WMH load interactions. Entries show the regression coefficient for the listed fixed effect followed by the associated p value for an F test on the marginal sum of squares.

	All (n=208)		CN (n=96)
	β	p	β	p
Intercept (mean FA)	0.370	<0.001	0.372	<0.001
NWI	-0.168	<0.001	-0.164	<0.001
NWI × NWI	-0.406	<0.001	-0.394	<0.001
WMH load	-0.012	<0.001	-0.013	<0.001
NWI by WMH load	-0.039	<0.001	-0.056	<0.001
NWI × NWI by WMH load	-0.082	<0.001	-0.105	<0.001

WMH: White Matter Hyperintensities

NWI: Neighbourhood White matter Injury

CN indicates cognitively normal