Sensitivity analysis of the impact of unmeasured confounding on the effect of baseline iron deficiency on risk of clinical malaria.

<p>The y-axis represents the hazard ratio for malaria infection comparing iron deficiency to iron replete after adjustment for average differences in prior risk represented by α on the x-axis. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0042670#pone-0042670-g002" target="_blank">Figure 2a</a> represents analyses in which net amount of confounding is specified for both iron status groups (bias parameter u = α^{(2×ID - 1)}). <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0042670#pone-0042670-g002" target="_blank">Figure 2b</a> represents analyses in which the amount of confounding was varied as a function of age (bias parameter u = α^{(2×ID - 1)×(1 - abs(age-36)/30}).