Table 2.
Multivariable Linear Mixed-Effects Modeling of the Outcomes: IgG Responses to Plasmodium falciparum and Plasmodium vivax Recombinant Antigens
| Variable | PfVAR2CSA | PfAMA1 | PfEBA175 | PfMSP2 | PfMSP3 | PvAMA1 |
|---|---|---|---|---|---|---|
| Gestation (weeks)a | −0.0003 (−0.01, 0.01) | −0.01 (−0.02, 0.002) | −0.01** (−0.03, −0.001) | −0.02** (−0.03, −0.01) | −0.01* (−0.02, −0.002) | −0.01# (−0.01, 0.001) |
| Longitudinal exposure groupb | ||||||
| Uninfected control high schizont lysate responder | 0.04 (−0.04, 0.13) | 0.12* (0.003, 0.24) | 0.10 (−0.06, 0.25) | 0.11# (−0.003, 0.22) | 0.02 (−0.05, 0.1) | 0.01 (−0.06, 0.09) |
| Uninfected case | 0.07 (−0.03, 0.17) | 0.05 (−0.08, 0.19) | −0.02 (−0.2, 0.16) | −0.06 (−0.18, 0.07) | 0.00003 (−0.09, 0.09) | 0.19*** (0.11, 0.27) |
| Species−specific infected case | 0.33*** (0.24, 0.42) | 0.58*** (0.47, 0.70) | 0.49*** (0.34, 0.65) | 0.34*** (0.23, 0.45) | 0.18*** (0.1, 0.25) | 0.08* (0.01, 0.16) |
| Gravidityc | ||||||
| Multigravida | 0.09* (0.09, 0.11) | 0.01 (−0.09, 0.11) | 0.14* (0.003, 0.27) | 0.08 (−0.02, 0.17) | 0.03 (−0.03, 0.1) | −0.07* (−0.13, −0.1) |
| Intervention groupd | ||||||
| Chloroquine | 0.02 (−0.04, 0.08) | 0.03 (−0.05, 0.11) | 0.03 (−0.08, 0.13) | −0.005 (−0.08, 0.07) | −0.03 (−0.08, 0.02) | 0.01 (−0.04, 0.06) |
| Prior Plasmodium sppe | ||||||
| Yes | −0.02 (−0.09, 0.04) | −0.01 (−0.09, 0.07) | −0.03 (−0.13, 0.08) | 0.01 (−0.06, 0.09) | −0.01 (−0.06, 0.05) | −0.01 (−0.08, 0.05) |
| Constantf | 0.11* (0.01, 0.21) | 0.18** (0.04, 0.32) | 0.3*** (0.12, 0.48) | 0.57*** (0.44, 0.69) | 0.1* (0.01, 0.2) | 0.16*** (0.08, 0.25) |
Values are coefficients (95% confidence intervals) of optical density values per unit change in covariate.
a Coefficients for gestation weeks is per 10 weeks gestation.
b Vs Uninfected control low schizont lysate responder (controls were selected for longitudinal analysis based on their responses to Schizont extract, Supplementary material).
c Vs Primigravida.
d Vs Placebo.
e Vs no prior Plasmodium spp. (species-specific).
f The mean antibody level for a woman at the start of pregnancy and the reference group of categorical variables = 0.***P < .001, **P ≤ .01, *P ≤ .05, #P < .1. The association between antibody levels with gestation was similar with respect to longitudinal exposure group, gravidity or intervention group (P-values for interaction terms > .1). The greater fluctuating responses in infected species-specific cases were confirmed by applying longitudinal exposure group as a covariate on the residual error of the model (data not shown).