Women become less sexually active and less interested in sex as they get older, on average, but there are still plenty of women who continue to have sex and maintain their sexual desire into their 60s and beyond, new research shows.

And a woman’s mental and physical health has more of an influence on her sex life than her age, according to the researchers.

Conventional wisdom holds that women’s sexual activity and interest dwindles as time goes by, but research has shown that some women maintain satisfying sex lives well into old age, Dr. Alison J. Huang of the University of California at San Francisco and her colleagues note in the Journal of the American Geriatrics Society.

To investigate what factors might be associated with sustained interest in sex, they had 1,977 racially and ethnically women, aged 45 to 80 years old, fill out questionnaires on their physical, mental and sexual health. Just over two-thirds were married or living with a partner.

Forty-three percent of the women overall said that their interest in or desire to have sex was “moderate to very high” over the past three months, while 60 percent reported some sexual activity in the previous three months.

For women 65 and older, 28 percent reported at least moderate interest in sex during the past three months, and nearly 37 percent had engaged in sexual activity during that time.

Fifty-seven percent said they were at least moderately sexually satisfied. The sexually inactive women were more likely to be satisfied with their sex lives if they were older.

The most common reasons women cited for not being sexually active included lack of interest (39 percent), lack of a partner (36 percent), a partner’s physical problems (23 percent), and a partner’s lack of interest in sex (11 percent). Only about 9 percent of the women said that their own physical problems were the cause.

Being married or living with a partner more than tripled a woman’s likelihood of having sex at least weekly. The chances of having weekly sexual activity also rose with a woman’s scores on tests of mental and physical health.

The researchers identified some ethnic and racial differences among the women; for example, black women were more likely than white women to report at least moderate desire to have sex, but less likely to have sex weekly, while Latina women who were sexually active were more likely than sexually active whites to report being at least moderately satisfied with their sex lives.

Many factors could account for these differences, including cultural influences, Huang and her team note. “Additionally, there may be important differences in women’s willingness to acknowledge or report sexual activity and problems across racial and ethnic groups,” they add.

“Further research is needed to assess how these differences may influence medical discussions about sexual functioning in women of diverse backgrounds,” they conclude.

SOURCE: Journal of the American Geriatrics Society, August 2009.