The value of the biomarkers are they applicable for all age range? What if someone already had a heart attack, then what should be the normal values post incident?
AFAIU, for LDL and ApoB, the real danger lies in the area under the curve. Lifetime exposure. That's not to say that lifestyle improvement can't help in other ways, but the damage caused by LDL is very difficult (impossible) to reverse.
So, if you hit the point where you already had a heart attack, you really want to prevent any further damage, but the "accumulated" risk is still there.
I think that's part of what makes LDL so tragic. You should care about it your whole life, but when you are young, you just don't.
Worse, high LDL is becoming a thing in children as well, that's an extra decade of accumulation which has historically not happened.
I don't think people should panic about these things, but I think it highlights the importance of developing good habits early, and the role parents and society has in making those habits easy for young people to adopt.