Malaria risk and ANC in the REACH cohort. Using results from the multivariable model for confirmed malaria infections in Table 3, the estimated hazard ratio (HR) and 95% confidence intervals from the fit with log₂(ANC) are shown in red. The figure is scaled so that a study participant with the mean ANC value at 24 months has an HR of 1. The blue line shows the fit for the more flexible 4-degree of freedom penalized spline for ANC, to illustrate that the fit using log₂(ANC) is a good approximation. The green shaded area at the bottom of the plot shows the distribution of the ANC at 24 months. There is a non-linear correlation with greater decrease in risk (HR<1.00) at lower ANC values, compared to higher values, and a sharper decrease in malaria risk at ANC values below 3.0 x 10⁹/L.