Fig. 2

Changes in the blood concentration of immunoglobulin M plotted against a biologic and chronologic age difference BA − CA, and normalized age difference (BA − CA)/BA. Squares (second order polynomial fit: double-dotted line)—male participants; diamonds (second order polynomial fit: dotted line)—female participants. Note that large positive difference BA − CA corresponds to early age. Trend lines (a): female y = 0.0009x² − 0.0139x + 1.6008, R² = 0.0680; male y = − 0.0001x² + 0.0091x + 1.6232, R² = 0.0471. Trend lines (b): female y = − 0.890x² + 0.549x + 1.654, R² = 0.069; male y = − 0.890x² + 0.549x + 1.654, R² = 0.069