eTable 1. Comparison of Characteristics for Participants in Project Viva Included in Versus Excluded from The Analysis
Included in the analysis (n=1312)
Excluded from the analysis (n=788)
Manganese concentration (ng/g), median (25th,
75th percentile) 16.2 (13.1, 20.4) 16.0 (13.0, 19.7)
Age at enrollment (years), mean (SD) 32.3 (4.6) 31.0 (6.0)
Nulliparous, n (%) 642 (49%) 375 (48%)
Race/ethnicity, n (%)
White 956 (73%) 423 (54%)
Black 167 (13%) 179 (23%)
Hispanic 89 (7%) 63 (8.0%)
Other 100 (8%) 99 (13%)
Unknown 0 (0%) 24 (3%)
Maternal education, n (%)
College graduate 912 (70%) 428 (54%)
Less than college graduate 400 (31%) 336 (43%)
Unknown 0 (0%) 24 (3%)
Smoking status, n (%)
Never 900 (69%) 525 (67%)
Former 249 (19%) 140 (18%)
During pregnancy 163 (12%) 102 (13%)
Unknown 0 (0%) 21 (3%)
Pre-pregnancy BMI (kg/m2), median (25th, 75th
percentile) 23.5 (21.1, 27.1) 23.3 (20.8, 27.5)
Mean MAP in first trimester (mmHg), mean
(SD) 83.6 (6.6) 83.1 (6.6)
Hematocrit closest to manganese measurement
(g/dL), mean (SD) 36.9 (2.6) 36.6 (2.7)
Preeclampsia status, n (%)
Yes 48 (4%) 26 (3%)
No 1264 (96%) 731 (93%)
Unknown 0 (0%) 31 (4%)
Abbreviations: BMI, body mass index; MAP, mean arterial pressure; SD, standard deviation.
eTable 2. Relative Risk of Developing Preeclampsia in Relation to First Trimester Manganese Concentrations, Before And After Adjustment for First Trimester Nutritional Factors
First trimester manganese (ng/g) n Case (%) Adjusteda Adjusted + AHEI Adjusted + DHA&EPA
RR 95% CI RR 95% CI RR 95% CI
Lowest Tertile (5.4, 14.3)b 448 22 (5%) reference reference reference Middle Tertile (14.4, 18.7) 431 15 (4%) 0.81 0.43, 1.5 0.80 0.43, 1.5 0.80 0.43, 1.5 Highest Tertile (18.8, 44.3) 433 11 (3%) 0.50 0.25, 0.99 0.50 0.25, 0.99 0.50 0.25, 0.98
P for trend 0.04 0.04 0.04
Per 1 IQRw (7.3) increment 1312 48 (4%) 0.72 0.50, 1.0 0.72 0.50, 1.0 0.71 0.49, 1.0
Abbreviations: CI, confidence interval; IQRw, interquartile range width; RR, relative risk; AHEI, the alternative healthy eating index;
DHA, docosahexaenoic acid; EPA, eicosapentaenoic acid.
a Model adjusted for maternal age (continuous), race/ethnicity (white, black, Hispanic, other), nulliparous (no, yes), pre-pregnancy BMI (continuous), first trimester mean arterial pressure (continuous), and hematocrit value (continuous) that was closest to the blood draw for manganese measurement.
b Refers to the range (minimum, maximum) of manganese in each tertile.
