L. Stephen Coles

By ASTRID GALVAN, The Associated Press

PHOENIX (AP) — L. Stephen Coles spent his career studying the reasons why supercentenarians — or those who live to 110 or more — survived as long as they did.

He wanted to learn how to slow "and ultimately reverse" human aging within 20 years, as the website for the Gerontology Research Group, which he founded, states.

Coles died Wednesday in Scottsdale of complications arising from pancreatic cancer. He was 73 years old, according to two colleagues.

Coles lived in Los Angeles but was in Arizona toward the end of his life so he could be put in cryopreservation when he died, said Robert Young, who worked with Coles for 15 years.

Coles' colleagues describe him as a pioneer in the field of gerontology. Coles, also a university professor, spent decades tracking the world's oldest human beings. He studied their genomes and DNA sequences in hopes of finding out why some people outlive others by so many years.

"The major goal is that he believes that the primary driver of longevity was biological and not caused by the environment. He had 110-year-olds, and they smoked cigarettes. Not that it's OK to do bad things, but that the people who lived longest are the ones who had biological predisposition for living the longest," Young said.

He said Coles' more than 100 scientific journal articles made him a leader in his field and revolutionized the study of aging.

John Adams, another colleague, said Coles was an outgoing person with various interests.

"Although the effects of the chemotherapy and the treatments were debilitating, he remained mentally sharp. I was amazed at his strength and resilience," Adams said.

Coles married his second wife, Natalie, in 2007. She was more than a spouse; she also worked with Coles on his scientific research, Young said.

Coles is also survived by his daughter, Electra McBurnie, and granddaughter Cailyn McBurnie.