There are a few factors:

• Genetics- high cholesterol tends to run in some families.
• Diet- certain foods can cause increases in LDL cholesterol
  • fatty or processed meats
  • biscuits, cakes & pastries
  • snack foods like chips
  • deep-fried foods
  • many types of takeaway foods
  • eggs and dairy foods in excessive amounts may be problematic for cholesterol, but many experts now advise that eggs and dairy eaten in moderation can benefit health in a variety of ways, and should not be eliminated altogether.