If you spent -- or misspent --your youth as one of the legion of Grateful Dead fans and want to relive those glory days in retirement, Andrew Carle offers a prediction: One day there could be a senior housing complex devoted to former Deadheads just like you.

"You need about 200 people to have a senior housing retirement community and there are 70 million baby boomers," said Carle, an assistant professor at George Mason University in Fairfax, Va., who oversees the nation's only university program devoted to the study of senior housing. "You think you can't find 200 Grateful Dead fans for a retirement community? Of course you can!"

Deadheads may or may not want to form a retirement community, but recreational vehicle owners have started one in Texas -- and they are about to be joined by the likes of nudists and country music fans looking to build specialized senior centers known as "affinity housing."

Universities are leading the growing trend for affinity developments. There are now roughly 100 senior retirement homes Carle calls "university-based retirement communities" that associate themselves with a particular educational institution.

"Baby boomers are the most highly educated demographic in history -- 29 percent of us have a bachelor's degree or higher," Carle said. They are "looking for the trifecta in their retirement: intellectually stimulating, active and intergenerational environments. If you think of those three variables, you basically just described a college campus."

Another growing sector serves the gay, lesbian, bisexual and transgender (GLBT, also known as LGBT) community. It started with RainbowVision in Santa Fe, N.M., which opened in 2005 and is described by its developer, RainbowVision Properties Inc., as "the first LGBT Community for the Second Fifty Years." Rainbow Properties now has a counterpart in development in Vancouver, B.C., and two sites in California --Palm Springs and the Bay Area --are being considered for similar projects. And construction is scheduled to begin late next year on a GLBT seniors' community called Spirit on Lake at 13th and Lake streets in Minneapolis.

The GLBT community makes up "10 percent of the population but they're not 10 percent of senior housing, so we'll see more of these communities - and we should," Carle said. According to various estimates, there are between 1 million and 3 million GLBT people aged 65 and older in the United States.

Other affinity housing groups include the Escapees Club, an RV organization based in Livingston, Texas, which started an assisted-living community for members "whose travels are permanently ended because of age" or ill health. It allows retirees to sleep in their own RV at night and receive meals, medical and other services at an adult day care center called CARE (Continuing Assistance for Retired Escapees). Retirees prefer to stay in their RVs, Carle said, because they "feel as strongly about them as we do about our houses."

The country music world also may soon have a senior development aimed at aging musicians and fans in Tennessee. And in Florida, nudist organizations plan to build senior housing in the Tampa-St. Petersburg area. "Nudists are aging just like the rest of the country -- their average age is 50-something," said Carle. "Why should they have to change their lives because they don't want to wear clothes? I think it's an absolutely great idea."

Frank Jossi is a freelance writer based in St. Paul.

For more information, go to chhs.gmu.edu/assisted-living/index