Korean-American and Vietnamese-American women, who have high rates of cervical cancer, are less likely to be screened for the disease, according to two studies in Santa Clara County funded by the federal Centers for Disease Control and Prevention.

The recently released studies shed light on several aspects of Asian-American health, focusing on specific groups in Santa Clara County and other locations nationwide. Researchers say lumping all Asians together gives an inaccurate picture.

"When you average all the groups together, you lose the ability to identify the higher-risk groups," said Marjorie Kagawa-Singer, a researcher involved in the study looking at the overall health of Vietnamese-Americans in Los Angeles, Orange and Santa Clara counties, as well as Cambodians in Massachusetts.

That study found that only about 65 percent of Vietnamese-American women surveyed reported having a Pap smear in the past three years, compared with about 74 percent of Asians nationwide and almost 86 percent of the U.S. population.

The other CDC study, focusing on Korean-American women in Santa Clara County, found that in 2002, less than 75 percent of Korean-American women -- compared with about 92 percent of all California women -- reported ever having a Pap test, which screens for precancerous cells in the cervix.

Rates of cervical cancer for Korean-American women are about 15 cases per 100,000.

Cervical cancer is preventable; regular Pap tests can detect abnormalities before they become cancerous. Women are advised to have the test at least once every three years.

"It shouldn't have to happen," said 28-year-old Phung Pham of San Jose, whose mother had cervical cancer and died five years ago. "You just have to go get a Pap smear, it's so simple."

According to 1992 data from the National Cancer Institute, Vietnamese-American women have the highest incidence of cervical cancer, with 43 cases for every 100,000 women, a rate more than five times as high as white women.

Prevention programs have sought to address the problem. UC San Francisco researchers and community-based organizations in Santa Clara County have produced media campaigns -- including one featuring Pham -- a low-cost Pap screening clinic and a program that has enrolled about 1,000 Vietnamese-American women.

The Korean-American study, a joint effort by the UC Berkeley's Center for Family and Community Health and Asian Health Services in Oakland, surveyed more than 870 Korean-American women in Santa Clara County in 1994 and 2002.

Researchers surveyed women by phone and compared results with those for all California women in another survey being conducted at the same time.

Screening practices improved significantly among participants from 1994 to 2002. The percentage of Korean-American women who reported having had a Pap smear increased from 65 percent in 1994 to almost 75 percent in 2002.

Interviewers conducted the survey in Korean or English, with more than 90 percent of participants opting for Korean, said research coordinator Joel Moskowitz. He said language barriers often prevent Korean-Americans from getting screened for breast and cervical cancers.

"If you are going to a provider with a child that is an interpreter, you don't want them in the room when you are getting a Pap test," said Moskowitz, director of the UC Berkeley center.

Language also is a barrier to screening for Vietnamese-American and other Asian women, said Kagawa-Singer, associate professor at the UCLA School of Public Health.

"About 67 percent of Asian-Americans nationwide are first-generation -- and that's slightly higher here in California -- and they have limited English ability," she said.

Cultural influences play a large role in the lack of preventive screenings among many Asian groups, said Moon Chen, professor in the department of public health sciences at the UC Davis Cancer Center.

"The attitude toward screening is one that is foreign to many Asian-Americans," he said. "You go to the doctor if you have a problem. If you don't have a problem, you don't seek one out."

Pham agreed. Her mother was very modest, she said, a cultural value that probably prevented her from being screened.

"In Vietnam, having Pap smears is not something sought after," she said. "It's something that is very private so you keep it private. It's about exposing a very intimate part of yourself and that takes a certain amount of trust."

Raising awareness in the Vietnamese community is the first step, Pham said. Making screening affordable for women, especially poor, uninsured women, is the next step.