Uncertainty about how the United States will cope with growing tumult in the world has not dampened Warren Buffett's optimism for the country's prospects over the long term -- even 100 years into the future.

"Whenever I hear people talk pessimistically about this country, I think they're out of their mind," Buffett, the chairman of Berkshire Hathaway Inc, said Tuesday night.

Buffett spoke in New York at an event celebrating the 100th anniversary of Forbes magazine, and is on the cover of an issue featuring 100 of the world's greatest living "business minds."

The billionaire has transformed Berkshire since 1965 from a failing textile company into a conglomerate with more than 90 businesses in such sectors as insurance, railroads, energy and retail, and well over $100 billion of stocks.

Buffett said he expects the Dow Jones Industrial Average to be "over 1 million" in 100 years, up from Tuesday's close of 22,370.80. He said that's not unreasonable, given how the index was roughly 81 a century ago.

But he knows he won't be around to see it happen.

"When I hear talking about making it to 100, I get excited," he said. "I'm 87."

Buffett said he recently determined that of the 53,364 people in the United States who were at least 100 years old, the ratio of women to men was nearly 5-to-1.

"We should start thinking about a sex change," Buffett said, prompting laughter.

Nonetheless, he said long-term investing remains the way to go.

He noted that since Forbes created its first list of the 400 richest Americans in 1982 -- Buffett was worth just $250 million then -- some 1,500 different people have been included.

All with one thing in common.

"You don't see any short sellers," he said, referring to people who bet stock prices will fall.

"It has been 241 years since Thomas Jefferson wrote the Declaration of Independence," he said. "Being short America has been a loser's game. I predict to you it will continue to be a loser's game."

Forbes' list of top business minds included people with a variety of backgrounds.

Among them were Microsoft co-founder Bill Gates, Amazon.com founder Jeff Bezos, Facebook's Mark Zuckerberg and Sheryl Sandberg, Nobel Peace Prize winner Muhammad Yunus, architect Frank Gehry, media mogul Oprah Winfrey, and singers Bono and Paul McCartney.