Pap tests should begin within three years of first vaginal sexual activity and should be done at least every two to three years until age 70, according to Ontario guidelines. (CBC)

Nearly four of 10 urban women living in Ontario aren't getting regular Pap tests to screen for cervical cancer, a study has found.

Researchers found 61.1 per cent of women aged 25 to 69 living in metropolitan areas of the province had a Pap test during the calendar years 2003, 2004 and 2005.

Despite universal health insurance coverage, appropriate cervical cancer screening was significantly lower among women who were 50 years or older, living in low-income areas or recent immigrants, after adjusting for contact with doctors and pregnancy rates, Dr. Aisha Lofters and her colleagues reported in the July issue of the journal Medical Care.

Women with all three of these characteristics had a screening rate of 31 per cent, compared to nearly 71 per cent among women with none of these characteristics.

For the most part, cervical cancer is easily detected by regular screening, said Lofters, a family doctor and the study's principal investigator at St. Michael's Hospital in Toronto.

"There are a lot of competing interests for women. To go into a doctor's office when you're not sick requires the ability to do that — requires a job where you have the capability to take time off, requires not having to worry about child care," Lofters said Thursday.

Efforts to reduce the screening disparities should focus on women who are older, living in low-income neighbourhoods or recent immigrants, the study's authors concluded.

Doing so may require changes on the part of both physicians and patients, Lofters noted.

"From a physician's perspective, when we see a patient we have to remember to offer that woman a Pap test, regardless of her culture, regardless of our preconceived notion of whether or not she needs one."

Most deaths in women over 50

There is also the misconception that women don't need Pap tests once they reach menopause.

Ontario guidelines state that Pap tests should begin within three years of first vaginal sexual activity and should be done at least every two to three years until age 70.

Most deaths due to cervical cancer occur in women over 50, the researchers noted.

Lofters and her colleagues also found regional differences in cervical cancer screening rates, with the Central West region of the province having significantly lower rates than other regions.

"This finding may be related to its ethnic makeup, as over 25 per cent of the population is of South Asia descent. South Asian women have previously been highlighted as vulnerable to inadequate cervical cancer screening," the researchers wrote.

Navigating the health-care system can be difficult for women who do not speak the local language or have low health literacy, the study's authors said.

A shortage of nearby doctors and the influence of peers might also be other factors in the screening gap, they suggested.

The population-based study looked at database information for 2.3 million women living in metropolitan areas of the province, based on OHIP records and census data.

Cervical cancer accounts for just over one per cent of all female cancer deaths in Canada, according to the Public Health Agency of Canada. In 2008, about 1,300 Canadian women were diagnosed with cervical cancer, and about 380 died from it.