A new study finds that obese adults are less likely than thinner people to get essential preventative health care, despite their higher risk of disease.

Researchers at Duke University Medical Center found that obese white adults had lower rates of mammography, Pap testing and flu vaccination than normal-weight people did.

The reasons, the investigators say, cannot be determined from this study, and are likely to involve a number of factors. But "anti-fat bias" could be playing some role, they speculate.

The researchers base their findings on data from two studies that surveyed more than 10,600 U.S. adults between 1995 and 2000.