Variations with age
At the population level, for the leukocyte concentration, the best model
was the model without age as explanatory variable, indicating that the
leukocyte concentration did not vary with age (Table S2, 1A, Figure 1A).
For the lymphocyte, neutrophil and eosinophil counts, the models with
the quadratic age effect were better (Table S2). For the eosinophil
counts, all the models with (linear and quadratic) and without age were
competitive (Table S2). For the number of monocytes, the model with the
linear age effect had the lowest AIC, but the model with the quadratic
age effect was also probable (Table S2). The lymphocyte count decreased
until 7 years old, followed by a slight increase at older ages (Figure
1B), conversely to neutrophil (Figure 1C) and eosinophil counts (Tables
S2, 1A, Figure 1E). The monocyte count decreased with age (Tables S2,
1A, Figure 1D).