Table 2.

Fits of regressions of total volumes by tissue type over age in the no/low group

	Linear		Quadratic
-	age z	age p	age z	age p	age^2 z	age^2 p
Male+female
Gray matter	−13.600	0.000000	−6.530	0.000000	4.738	0.000002
White matter	24.370	0.138000	10.189	0.000000	−6.952	0.000000
CSF	4.058	0.000050	5.642	0.000000	−5.160	0.000000
Total	8.932	0.000000	7.769	0.000000	−6.598	0.000000
Male
Gray matter	−13.420	0.000000	−7.370	0.000000	5.550	0.000000
White matter	15.910	0.000000	4.584	0.000005	−2.468	0.013600
CSF	7.753	0.000000	9.710	0.000000	−8.697	0.000000
Total	6.611	0.000000	7.241	0.000000	−6.362	0.000000
Female
Gray matter	−6.143	0.000000	-	-	-	-
White matter	18.570	0.000000	9.663	0.000000	−7.172	0.000000
CSF	−3.331	0.000865	-	-	-	-
Total	6.056	0.000000	3.608	0.000309	−2.818	0.004829
Age-by-sex interaction
Gray matter	−5.874	0.000000
White matter	−3.104	0.001910
CSF	8.150	0.000000
Total	1.483	0.138000