Complex sentence: Lifestyle diseases (also sometimes called diseases of longevity or diseases of civilization interchangeably) are diseases that appear to the increase in frequency as countries become more industrialized and people live longer.
Split into simpler sentences: Lifestyle diseases (also sometimes called diseases of longevity or diseases of civilization interchangeably) Lifestyle disease is defined as a disease linked with the way people live their life. The diseases that appear to the increase in frequency as countries become more industrialized and people live longer.