Table 2:

Effects of age, APOE ε4, and sex on rates of change in HC

HC Measure	b₀	b_Cog	b_Edu	b_Age (SE; P)	b_APOE (SE; P)	b_Sex (SE; P)
Hippocampus	−0.64^a	−0.06^a	−0.04^a	−0.04^a (.01; .002)	−0.42^a (.13; .002)	−0.25^a (.13; .044)
Amygdala	−0.41^a	−0.03	−0.05	−0.04^a (.02; .028)	−0.63^a (.16; 1 × 10⁻⁴)	−0.53^a (.15; 5 × 10⁻⁴)
Entorhinal	−0.39^a	−0.04	−0.05	−0.04^a (.02; .025)	−0.52^a (.17; .003)	−0.49^a (.16; .002)
Inferior parietal	−0.50^a	0.00	−0.01	−0.01 (.01; .5)	−0.14 (.10; .2)	0.03 (.10; .8)
Middle temporal	−0.61^a	−0.02	−0.02	0.00 (.01; .7)	−0.19 (.12; .1)	−0.02 (.11; .9)
Med-orbito-frontal	−0.48^a	−0.03^a	−0.01	−0.01 (.01; .5)	−0.18^a (.09; .050)	−0.03 (.09; .8)
Whole brain	−0.41^a	0.00	−0.01	0.00 (.01; .8)	−0.08 (.06; .2)	−0.03 (.06; .7)
CDR-SB	0.10^a	–	−0.01	0.00 (.00; .4)	0.01 (.05; .9)	−0.02 (.04; .6)
ADAS-Cog	−0.29^a	–	−0.04	0.05^a (.02; .008)	0.27 (.20; .2)	−0.21 (.18; .2)
MMSE	0.02	–	−0.02	−0.02^a (.01; .009)	−0.14 (.08; .1)	−0.06 (.08; .4)

Note:—b-Values are coefficients in Equation 1; for structural measures, units are annual thickness or volume change as a percentage of baseline size (%/year), and for cognitive measures they are annual score change, per ADAS-Cog unit in the case of b_Cog, and per year in the case of b_Edu and b_Age. ROIs: N = 188; mean age = 76.30 years; mean ADAS-Cog = 6.17; mean years education = 16.02. Clinical: N = 211; mean age = 76.35 years; mean years education = 16.03. SE indicates standard error; Med-orbito-frontal, medial orbito-frontal cortex.
↵a Values significant at P ≤ .05.
Values in the b₀ column show the expected rate of change for an APOE ε4−negative male subject of mean age, mean education, and with a mean level of cognitive function. The remaining columns show the additional rate of change caused by the other factors of interest, and the amount of change experienced by a given individual can be calculated on the basis of the sum of the relevant coefficients. For example, for hippocampal atrophy, each point above the mean baseline ADAS-Cog score contributes an additional 0.06% to the annual atrophy rate; each year of education below the mean contributes an additional 0.04% to annual atrophy rate, as does each year of age above the mean at baseline; presence of an APOE ε4 allele contributes an additional 0.42% to rate of decline, and female sex contributes an additional 0.25%. Thus, an APOE ε4⁺ female subject, of mean age, education, and cognitive function at baseline, would show a hippocampal atrophy rate of 1.31% (0.64 + 0.42 + 0.25).