Figure 1. Two dimensional principal component analysis plot, showing that exhaled breath profiles (breathprints) of subjects ≥ 50 years of age (left, triangles) are indistinguishable from those of subjects < 50 years of age (left, circles). Similarly the breathprints of male subjects (right, circles) could not be distinguished from those of female subjects (right, triangles). REGR: relative elemental growth rate.