Over Michael Jackson's chart-topping music career, his health has commanded as much publicity as his hit songs.
Plastic surgery, mysterious hospitalizations and reports of pill popping have long plagued the King of Pop.
The circumstances surrounding Jackson's death Thursday were sketchy, but the pop icon apparently collapsed from cardiac arrest at his rented Bel-Air home.
The reclusive singer was reportedly found unconscious and not breathing. Paramedics performed CPR and rushed him to the hospital -- a six-minute drive away -- where he was pronounced dead.
Jackson's unexpected death at age 50 during a comeback attempt stunned the world despite a history of health problems -- some real and others rumored -- that have been fodder for tabloids and gossip columns speculating wildly about his woes.
In the early 1990s, Jackson's dermatologist revealed the singer had a skin disorder known as vitiligo, which leads to white patches on the skin. Over the years, Jackson underwent numerous plastic surgeries, including a nose job.
Jackson was also widely reported to be addicted to painkillers from pain he developed after he was burned while filming a Pepsi commercial in 1984.
During his 2005 molestation trial in which he was acquitted, Jackson appeared gaunt and had recurring back problems he attributed to stress. The trial was interrupted several times by hospital visits. Jackson once even appeared late to court dressed in his pajamas after an emergency room visit.
Last year, a celebrity biographer claimed Jackson suffered from a rare respiratory disease and was in need of a lung transplant -- a claim his publicists have denied.
Chatter about Jackson's health surfaced again last month after his representatives postponed several of his London comeback shows, citing the need for more rehearsal time. A previous attempt by Jackson to relaunch his career was sidetracked amid reports of ill health and court action.
Jackson was in the process of preparing for an epic 50-concert stand in London that had him rehearsing long hours. Jackson was described "very frail," but worked hard, Johnny Caswell, a principal at Centerstaging, where Jackson rehearsed for the concerts, told the Los Angeles Times.
Michael Levine, a Hollywood publicist who represented Jackson in the early 1990s, said that the pressures of emotional, physical, legal, financial and spiritual dysfunction caught up with Jackson.
"It's a toxic mix that nobody can withstand," he said.
Jackson died at UCLA Medical Center in Los Angeles. His brother, Jermaine, told a news conference that Jackson was believed to have suffered cardiac arrest, a condition that afflicts 300,000 Americans a year.
"However, the cause of his death is unknown until results of the autopsy are known," his brother said.
Cardiac arrest strikes without warning. It occurs when the heart's electrical system goes haywire and the heart suddenly stops beating. It can occur after a heart attack or be caused by other heart problems.
"In the absence of details, it's hard to know if he had a cardiac arrest or if he stopped breathing," said Dr. Leslie Saxon, chief of cardiovascular medicine at the University of Southern California.
Fewer than 5 percent of those who suffer cardiac arrest survive, according to medical experts.
During cardiac arrest, brain cells die within minutes. It is reversible if a person receives an electric shock to the heart to restore normal heartbeat.
Each minute that passes without restoring normal heart rhythm, the odds of survival decreases by 10 percent.
"There's a huge public health message," said Dr. Clyde Yancy, a heart specialist at Baylor University Medical Center in Dallas and president of the American Heart Association.
"When someone collapses abruptly, call 911, and if they're not breathing, start CPR," Yancy said.