Age 7 & less Typical
studies, 1930s on, atherosclerosis
, an accumulation of white blood cells, mostly macrophages, have been observed to have invaded into the walls of arteries (not veins) by about age 7 on average.
Rarely, about 1 in 6-8, 000 live births, it is already present at birth. On the other hand, a few individual remain free of this behavior well into adulthood.