Arteries, Blood Volume

If with age or disease arteries narrow down to 50% in diameter as they say, that means 2/3 in space volume inside the artery that means that those people have up to 1/3 less blood than normal people, (veins do not narrow or dilate accordingly, half of the blood is stored in arteries). Never heard of anything like this, there must be something wrong with this theory.

Vitamin D, Cholesterol Mechanism

Since vitamin D is produced in your skin from cholesterol under sun exposure, is it possible your body allows more cholesterol in blood (and tissues like skin) as a response to vitamin D deficiency due to chronic lack of sun exposure?

Vitamin D deficiency high cholesterol

Inuit population need to intake much cholesterol in order to make vitamin D only in the skin of their face. Could this be the reason those from mongol race have big faces? Also fair skin allows the very little sunshine into your skin more easily.