I have a question at the end of the post that I hope you will answer.

When I was attending college over 20 years ago, in one of the classes--(I
don't recall which class) the professor explained to the class that a
typical person's entire life is like a bell curve. The top of the bell
curve represents 40 years old. The professor said that when typical person
is on the left side of the curve (1-39 years old)--he or she does not have
any serious health problems that cause death or the person to be disabled.
On the otherhand, when the person is on the wrong side of the curve
(41-death)--the body starts to have more and more health problems. As he
or she gets near the bottom of the bell curve--death happens. Do medical
experts still believe this theory today and is this theory still discussed
in colleges? (I should note that the professor was talking about typical
people--not rare cases such as childhood cancer).
Thanks in advance,
Jason