Table 2.

The effect of group and group × age on brain volume measurements.

Measurements	FXPC− Vs. Controls			Older Controls Vs. FXPC+*			Older FXPC− Vs. FXPC+*
	RAdj.	β (SE) (ml)	P	RAdj.	β (SE) (ml)	P	β (SE) (ml)	P
Cerebellar volume	0.43		< 0.001	0.56		< 0.001		< 0.001
Age		−0.36 (0.04)	< 0.001		−0.52 (0.11)	< 0.001	−0.52 (0.11)	< 0.001
Group		−0.18 (2.58)	0.94		23.7 (1.89)	< 0.001	14.1 (2.19)	< 0.001
Age × group		−0.15 (0.06)	0.017		-	-	-	-
Brainstem volume	0.34		< 0.001	0.63		< 0.001		< 0.001
Age squared		−0.001 (0.0005)	0.009		-	-	-	-
Age		0.093 (0.036)	0.010		−0.22 (0.05)	< 0.001	−0.22 (0.05)	< 0.001
Group		−0.068 (0.67)	0.92		4.77 (1.11)	< 0.001	−0.44 (1.29)	0.730
Age × group		−0.054 (0.017)	0.002		0.15 (0.07)	0.023	0.31 (0.08)	< 0.001
Ventricular volume	0.52		< 0.001	0.59		< 0.001		< 0.001
Age squared		0.006 (0.002)	0.007		-	-	-	-
Age		0.107 (0.15)	0.48		1.52 (0.30)	< 0.001	1.52 (0.30)	< 0.001
Group		4.73 (1.67)	0.003		−21.0 (6.75)	0.002	−3.67 (7.82)	0.64
Age × group		-	-		−0.69 (0.40)	0.09	−1.39 (0.51)	0.007
Whole brain volume	0.75		< 0.001	0.69		< 0.001		< 0.001
Age		−3.66 (0.23)	< 0.001		−3.43 (0.63)	< 0.001	−3.43 (0.63)	< 0.001
Group		13.2 (14.2)	0.35		109.7 (10.4)	< 0.001	72.0 (44.3)	< 0.001
Age × group		−0.93 (0.36)	0.009		-	-	-	-

Abbreviations: FXPC−, fragile X premutation carriers without fragile X-associated tremor/ataxia syndrome; FXPC+, fragile X premutation carriers with fragile X-associated tremor/ataxia syndrome.

Bold, significant at 5% false discovery rate.

^*The comparisons of FXPC+ with older controls and FXPC− were performed in the same regression analyses.