Appendix 7—table 1. Unadjusted association between gSG6 IgG seropositivity and log Plasmodium spp prevalence.

Variable	log odds ratio (SE)	95% CI	p-Value	RE
Fixed part
log Plasmodium spp. prevalence	0.46 (0.32)	–0.16–1.08	0.148
Random part
${\psi }_1$ ‡				17.21
${\psi }_2$				1.25
${\rho }_1$ §				0.85
ℓ				–2597.2
Model fit indices
Akaike’s information criterion				5202.5
Bayesian information criterion				5215.9

Any Plasmodium species infections (including prevalence estimates of P. falciparum only, P. vivax only, both P. falciparum and P. vivax and untyped infections): log odds ratio and standard error (SE), 95% confidence interval (95% CI), p-value, random-effect components (RE): variances (ψ), conditional intraclass correlation coefficient (ICC) (ρ),* and model log likelihood (ℓ) from generalised linear multilevel modelling (mixed effects, logistic).^† This analysis is based upon n = 212 study-specific observations from 14 studies. Of note, six studies that measured Plasmodium spp. prevalence and IgG antibodies to gSG6 were excluded from this analysis as five only reported gSG6 IgG levels and one was a case–control study.

^* ρ = $\frac{{\psi }_k+...+{\psi }_{nk}}{{\psi }_k+...+{\psi }_{nk}+{\pi }^2/3}$ , where ${\psi }_k$ through ${\psi }_{nk}$ are random-effect variance estimates pertaining to each of the respective variance components (see table notes ^{‡ and §}) from the generalised linear multilevel modelling (mixed effects, logistic) for a specific ICC estimate.

^† Generalised linear multilevel modelling (mixed effects, logistic) estimating the association between the log prevalence of any Plasmodium spp. infection and anti-gSG6 IgG seropositivity with random effects for study-specific heterogeneity in gSG6 IgG seroprevalence and study-specific heterogeneity in effect of Plasmodium spp. prevalence.

^‡ ${\psi }_1$ and ${\psi }_2$ represent variances of the random effects for study and effect of Plasmodium spp. prevalence, respectively.

^§ ${\rho }_1$ represents the conditional ICC for salivary antibody observations from the same study and with the median Plasmodium spp. prevalence.