BY 1990, more than half of all American women will be over 40 - a demographic shift that will probably register only slowly on the nation's youth-oriented psyche. Yet already the diverse needs and interests of midlife and older women are gaining new voice and visibility.
Last month Angela Lansbury, the 63-year-old star of the TV series ``Murder, She Wrote,'' released an exercise video targeted at ``mature, intelligent women who are as much interested in achieving an overall happy and rewarding life style as in losing a few pounds.'' And a new line of ``older woman'' store mannequins will make their debut next month.
McCall's magazine has just introduced a ``silver edition'' for women aged 50 to 64. And earlier this year Frances Lear, former wife of TV producer Norman Lear, committed part of her $112 million divorce settlement to launch an upscale magazine ``for the woman who wasn't born yesterday.''
Called Lear's, the magazine celebrates the joys and accomplishments of women over 40. Models must be between the ages of 33 and 60, and editors refuse to airbrush laugh lines and crows' feet from photos.
The fifth issue of Lear's, now on newsstands, features a glamorous 50-year-old Texas farmer, Imo Brockett, as its ``cover woman.'' Dressed in a strapless black gown, Ms. Brockett looks more like a socialite out of the pages of Town & Country than someone who presumably gets dirt under her fingernails during a day's work.
Still, any reader who wants to learn more about Ms. Brockett and her career will be disappointed. As one of half a dozen women appearing in a photo spread headlined ``American Beauties,'' Brockett is described only as a ``native American farmer, wife, mother, grandmother.''
Too bad, because she just might have an interesting story to tell - one that could be more useful to a Lear's reader than, say, the magazine's double-page photo of a pair of aviator glasses, or its full-page picture of a red-kneed tarantula crawling on an 18-karat gold and diamond bracelet. Even upscale women, after all, can use a good role model now and then.
Meanwhile, crosstown in the real world live midlife women who could hardly afford to buy a single issue of Lear's - to say nothing of its life style.
For unglitzy contrast, consider the plight facing 1.5 million nursing aides and home health care workers, most of them middle-aged women, who are the subject of a bleak new report issued by the Older Women's League (OWL).
These paid care givers of the elderly, the OWL report says, are ``among the most exploited workers in our nation.'' Although responsible for virtually all the daily personal care of nursing home residents, they are paid an average of just $4.50 an hour - less than many fast-food workers earn.
``The majority of chronic-care workers are midlife women who are the sole support for their families,'' said Lou Glasse, president of the group. ``They are doing difficult work for so little pay that they themselves are likely to end up without adequate resources to avoid poverty in their old age.''
For eight years the Older Women's League has been working to correct economic and social injustices such as these, tackling issues such as pension reform, social security credits for homemakers, and care giving. The league spotlights not only problems but also legislative progress.
In their contrasting styles, both Lear's and the Older Women's League are combating the double standard that more cruelly penalizes mature women than men.
As the ranks of older women grow, the education - for it is nothing less than that - will become more sophisticated than advocacy groups and upbeat magazines.
The best hope is that we will look back at these beginnings as enlarging the perception of a fuller life, for men as well as women.