Although his death is listed as accidental, world-renowned strongman Mike Jenkins' long-term use of anabolic steroids and possibly of a performance supplement played key roles in his demise, Dauphin County Coroner Graham Hetrick said Friday.

Hetrick said the direct cause of death for Jenkins, a county resident who died in his sleep in November, was an "immensely" enlarged heart that the coroner attributed to Jenkin's use of anabolic steroids.

Jenkins' heart was at least twice the size of an average man's, Hetrick said.

Strongman Mike Jenkins

In addition to the steroid use, Hetrick said the presence of

DMAA,

methylhexanamine, was found in Jenkins' system.

DMAA

is a stimulant that increases heart rate and blood pressure and constricts blood vessels.

Jenkins, 31, who owned the local CrossFit Gamma gym, was among the globe's premier strength athletes.

The 6-6, 400-pound competitor placed fourth in the 2013 World's Strongest Man competition and in 2012 won the Arnold Strongman Classic, which is named for famed strongman and bodybuilder Arnold Schwarzenegger. Jenkins also had played football for James Madison University.

His death sent a ripple of grief and disbelief through the strength sports world.

"He was a big person," Hetrick said, citing the amazing physical feats Jenkins could perform. "You can go on YouTube and see this guy. It's frightening."

Hetrick said it took seven months to make a ruling on the death because specialized toxicology testing had to be done. His office doesn't normally have to do screening for the types of substances found in Jenkins' body, he said.

Steroids are used to promote body mass and increase strength, and the health problems that can result from their long-term use are well documented.

DMAA

is also used to enhance performance and has amphetamine-type qualities although it is not an amphetamine, Hetrick said, and it is not regulated by the

U.S.

Food and Drug Administration. The long-term effects of

DMAA

use aren't fully understood, he said.

He said the enlargement of Jenkins' heart led to complications with other organs, including his liver.

It is unlikely that Jenkins knew the extent of the damage that was being done to his body, Hetrick said. However, he said that soon before his death Jenkins did experience possible symptoms of those health problems.

Jenkins had just returned from a trip to China, was feeling ill, had lost 30 to 40 pounds of body weight and apparently believed he had contracted a disease while overseas, the coroner said. "He indicated to his wife that he wasn't lifting like he normally did," Hetrick said. "He was tired."

Given the cause, and to some degree the uncertainties surrounding Jenkins' death, Hetrick advised parents to keep a close watch on what, if any substances their children might be taking to try to excel in athletics or in the weight room.

"I would urge parents to monitor what their kids are buying on the internet as far as performance enhancers and stimulants," he said.