Fig. 3.

Multiple fractional polynomials of the age profile of iron status and inflammation by malaria parasitaemia. Scatterplots of age in years (x axis) against A) log ferritin with the fitted fractional polynomials: for parasite positive (red): concentration = m₁*(age in years) + c (n = 69); and parasite negative (black): concentration = m₁*ln(age in years) + m₂*(ln(age in years))² + c (n = 496); B) log soluble transferrin receptor with the fitted fractional polynomials: for parasite positive (red): concentration = m₁*(age in years) + c (n = 70); and parasite negative (black): concentration = m₁*(age in years)^− 0.5 + m₂*(age in years)^− 0.5 *ln(age in years) + c (n = 498); C) log ferritin index with the fitted fractional polynomials for parasite positive (red): concentration = m₁*(age in years) + c (n = 69); and parasite negative (black): concentration = m₁*(age in years)^− 0.5 + m₂*ln(age in years) + c (n = 481); and D) log CRP with the fitted fractional polynomials: for parasite positive (red): concentration = m₁*(age in years) + c (n = 69); and parasite negative (black): concentration = m₁*(age in years) + c (n = 496). Dotted lines indicate 95% confidence intervals. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)