Table 1: Descriptive statistics.

𝑁 (%)Social Engagement
(Range −0.79, 1.09)
(SD)Total brain volume
(Range 880.6, 1449.3)
(SD)

All348(100%)0.01(0.33)1137.4(100.4)
Age
 48–5982(23.6%)−0.07(0.35)1187.5(94.6)
  60–6492(26.4%)0.04(0.32)1161.3(90.6)
 65–6984(24.1%)0.02(0.29)1123.9(81.8)
 70–8290(25.9%)0.07(0.33)1079.7(100.4)
𝑃 = 0 . 0 2 8 𝑃 < 0 . 0 0 1
Race/ethnicity
 White/Non-Hispanic315(90.5%)0.02(0.32)1141.6(99.9)
 All other33(9.6%)−0.05(0.40)1097.1(97.9)
𝑃 = 0 . 2 5 𝑃 = 0 . 0 1 5
Educational attainment
 <High school25(7.2%) −0.05 (0.41)1083.1(74.7)
 High school90(25.9%) −0.05 (0.32)1139.8(97.4)
 High school + trade school167(48.0%)0.03(0.30)1135.8(101.6)
 College degree56(16.1%)0.04(0.34)1171.6(92.2)
 Graduate degree10(2.9%)0.28(0.41)1086.1(137.9)
𝑃 = 0 . 0 1 8 𝑃 = 0 . 0 0 2
Hypertension
 Yes180(51.7%)0.01(0.32)1116.6(97.5)
 No168(48.3%)0.01(0.33)1159.6(99.0)
𝑃 = 0 . 9 7 𝑃 < 0 . 0 0 1
Diabetes
 Yes54(15.5%)−0.01(0.29)1098.8(90.5)
 No294(84.5%)0.02(0.34)1144.4(100.7)
𝑃 = 0 . 5 9 𝑃 = 0 . 0 0 2
Control status
 Population-based control43(12.4%)0.12(0.29)1103.5(100.5)
 Former lead worker305(87.6%)0.00(0.33)1142.1(99.6)
𝑃 = 0 . 0 1 8 𝑃 = 0 . 0 1 8

All 𝑃 -values from analysis of variance (ANOVA) tests.