In the years leading up to his sudden death, Elvis's health had deteriorated due to drug abuse and a diet full of junk food.

once commented on Elvis's passing. He suggested that the icon's long-standing problem with constipation aggravated by his diet and medication habits led to what is known as Valsalva's maneuver.

The rock n' roll icon, who would have been 90 on Jan. 8, gave what would be his final performance in Indianapolis. Look back ...