Table 2.

Results from linear mixed effects model for log₁₀-transformed Immunoglobulin gG (IgG) antibody titers. Reported are the estimated fixed effects along with their standard error and P-values.

Dependent variable: IgG levels (AU/ml) log10-transformed
Variables	Value	Std. Error	P-value
Intercept	4.51	0.0193	<0.001
Month	−0.233	0.0009	<0.001
Age (years, >60 as reference)
18–30	0.219	0.0231	<0.001
30–40	0.136	0.0205	<0.001
40–50	0.056	0.0199	0.0053
50–60	0.050	0.0199	0.0120
Gender (female)	0.070	0.0135	<0.001
T0 (titers >50 AU/ml)	0.155	0.0422	0.0002
Interactions
Months xT0 (titers >50 AU/ml)	0.062	0.0062	<0.001

AIC = 1849.178; Marginalized R² = 0.71; Conditional R² = 0.91.

AU = arbitrary units.