CHICAGO -- Grandmother or not, Ann Dickerson isn't interested in prescription drugs, medical insurance, RVs or the other products aimed at over-50 consumers.

Dickerson has a different mind-set as she powers over the Rocky Mountain foothills on her mountain bike every day, staying ahead of stereotypes about aging and marketers' expectations.

"I think of myself as young," said the 51-year-old resident of Golden, Colo. "I still don't need arthritis drugs -- I don't know what they're after me to get."

The over-50 crowd never has been a priority for most marketers. But the new wave of active, affluent baby boomers such as Dickerson that's swelling the ranks of that age group is making them harder to ignore.

Americans age 50 and above control $7 trillion, or 70 percent, of all U.S. wealth, bring in $2 trillion in annual income and account for 50 percent of all discretionary spending. Yet they are the target of only about 5 percent of advertising dollars, according to gerontologist Ken Dychtwald, president of the Age Wave think tank in San Francisco.

Dychtwald thinks marketers should be pitching more concepts such as home remodeling, anti-aging medicines and sports cars to 50-and-ups, instead of old-age products for "mature" consumers. But the first step is to focus on them at all.

"Most companies are not paying any attention whatsoever to people over 50," he said. "It's absolutely unbelievable."

The number of 18- to 34-year-olds shrank by 9 million between 1990 and 2000, he noted, while the 50-plus group rose by 12 million as the first boomers -- born from 1946 through 1964 -- surpassed the half-century mark.

"There has definitely been progress," Dychtwald said of the acknowledgment of older consumers in the advertising world. "But the progress is trivial in proportion to the demographics and the spending heft of people over 50."

At least one industry has responded to the demographic shift, as anyone who has watched TV commercials lately can attest.

"If I see another drug commercial for dysfunctional sexual performance, arthritis or the host of other drugs being pushed by pharmaceutical companies, I think I'm going to OD," said Harriet Brand, 55, a New Yorker. "When they market to baby boomers, they consider us geriatric cases with failing bodies and brains.

"The reality is that we're finally past paying for college tuitions, we've amortized much of our house mortgages and we have more dispensable income than any other age group," she said. "But shhh, don't let the marketers know. We'll be bombarded."