Partitioned age effect
Over the course of an individual’s life, the lymphocyte count decreased with age (Figure 1B) while the neutrophil count increased (Table 1B, Figure 1C). Moreover, the difference between within- and between-individual effects was significant for both lymphocytes and neutrophils (significant average age terms in Table 1C), suggesting that individuals with a low lymphocyte and high neutrophil counts selectively disappeared from the sampled population (Figures 1B, 1C). The leukocyte concentration and the monocyte and eosinophil counts did not vary when an individual aged (Table 1B). We also found that males had less lymphocytes than females (Tables 1B, 1C).