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).