Why do scientists believe that ancient egyptians had heart disease?

Atherosclerosis was found from the CT scans conducted to hundreds of bodies. It is when the arteries become narrower caused by fats that lead to heart attack and strokes.

It could be because of smoking and obesity. However, the case does not only happen because of those, it can also be due to the infections, parasites or even the inevitable inhaling of smoke from cooking using fire.

Tobacco was not used in Ancient Egypt so researches believed that atherosclerosis was caused by infections of poor hygiene. Lack of sanitation and living close to their animals might have also caused this. Because of lack of information, they were unaware that germs live among those unclean places where they live in, thus causing infection.