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. Author manuscript; available in PMC: 2017 Aug 15.
Published in final edited form as: Nature. 2017 Feb 15;542(7641):348–351. doi: 10.1038/nature21369

Extended Data, Table 2. Group differences in developmental trajectories and cross-sectional volumes by age.

Key: LR = low risk, HR-neg = High Risk negative, HR-ASD = High Risk with Autism, Year 1 = 6-12 month period, Year 2 = 12-24 month period, Pairwise Group Comparison (p<.05), Adjusted Group Mean = Model estimated group means at the specified time point, SE = standard error, Unit of brain volume measures for trajectory and cross-sectional analyses is mm3. Unit for surface area is mm2, and for cortical thickness is mm. Slope is represented as change/months. The sample for the piecewise linear model included subjects with complete data at all three visits (6m, 12m, and 24m).

LR(a) (N=42) HR-neg(b) (N=91) HR-ASD(c) (N=15) Overall Group Comparison Pairwise Group Comparison
Measure Trajectory Slope SE Slope SE Slope SE df1, df2 F P
Total brain volume 1s1 Year 24046 1416 25329 980 27298 2399 2,289 0.72 0.49
2nd Year 10928 523 10277 360 13318 1060 2,289 3.83 0.02 c>(a, b)
Surface Area 1st Year 972 71 1061 49 1331 125 2,289 3.13 0.04 c>(a, b)
2nd Year 864 38 814 26 960 75 2,289 1.93 0.15
Cortical Thickness 1st Year -0.024 0.003 -0-024 0.002 -0.024 0.006 2,289 0.00 0.99
2nd Year -0.025 0.002 -0-021 0.001 -0.026 0.004 2,289 1.44 0.24
Cross-sectional Visit age Adjusted Group Mean SE Adjusted Group Mean SE Adjusted Group Mean SE df1,df2 F P
Total brain volume 6 months 748890 9269 762420 6297 771403 15604 2,289 1.08 0.34
12 months 893167 11550 914391 7843 935189 19590 2,289 2.10 0.12
24 months 1024297 12475 1037714 84442 1095002 21563 2,289 4.14 0.02 c>(a, b)
Surface area 6 months 51736 541 52611 367 52779 914 2,289 1.03 0.36
12 months 57570 671 58979 455 60764 1144 2,289 3.32 0.04 c>a
24 months 67933 765 68746 518 72281 1323 2,289 4.16 0.02 c>(a, b)
Cortical thickness 6 months 5.98 0.040 5.96 0.027 6.05 0.067 2,289 0.69 0.50
12 months 5.84 0.037 5.82 0.025 5.91 0.064 2,289 0.82 0.44
24 months 5.54 0.029 5.56 0.020 5.59 0.051 2,289 0.48 0.62