NEW YORK (Reuters Health) – Obese women, particularly white obese women, are less likely than their thinner peers to be screened for breast and cervical cancers, researchers reported on Monday.

In a review of 32 previously published studies, researchers found that obesity was consistently linked to lower rates of breast and cervical cancer screening among white women. Fourteen studies focused on cervical cancer, 10 on breast cancer and eight looked at colorectal cancer.

Sarah S. Cohen and colleagues at the University of North Carolina, Chapel Hill, report the findings in the online edition of the journal Cancer.

The National Cancer Institute recommends that women have a mammogram to detect breast cancer every one to two years, starting at age 40, and a Pap test to screen for cervical cancer at least once every three years, beginning about three years after they start having sex.

It's not certain why obese women are less likely to get these screening tests, as few studies have been designed to look at the underlying reasons, according to Cohen and her colleagues.

However, they point out, some research shows that obese women often worry about embarrassment in the exam room, negative reactions from healthcare providers and "lectures" about their weight.

One of the studies in the review also found that obese women often complained that the gowns, exam tables and equipment at doctors' offices were too small for them.

Another possibility, according to Cohen's team, is that doctors less often recommend cancer screening to obese women than to thinner women. But there was a lack of evidence supporting this in the studies reviewed. One study found that obese women were more likely to say their doctor had advised them to get a Pap test.

In contrast to the case with breast and ovarian cancer screening, Cohen's team found no consistent evidence that obesity lowered the odds of colon cancer screening.

About half of the studies on colon cancer screening found lower screening rates among obese women, while the rest did not.