Obesity and cancer screening: Does race and gender also play a role?

"Numerous studies have suggested that obesity constitutes an obstacle to cancer screening, but a deeper examination also considering the role of race/ethnicity and gender in the equation has not been done before," said Heather Bittner Fagan, MD, FAAFP MPH, lead author and associate professor, Thomas Jefferson University and director of Health Services Research, department of Family and Community Medicine, Christiana Care Health System. "A greater understanding of the relationship between cancer screening and obesity, race/ethnicity and gender can also help explain the association between obesity and increased cancer mortality."

Obesity is second only to tobacco use as a risk factor for cancer and is associated with increased mortality for all cancer combined as well as for cancer of specific sites, including cancer of the colon/rectum, prostate, breast, and cervix.

Analysis

In cervical cancer screening, increasing weight was consistently associated with lower rates of Pap smear use. Studies showed this to be most notable in white women, with black women, particularly black women of high socioeconomic status showing an absent or less strong association.

In contrast, prostate cancer screening levels were consistently shown to increase with weight. In three of four studies obese men were more likely to receive a PSA test for prostate cancer screening than their normal weight peers. This unique finding seems to remain across race/ethnicity differences.

"This could be explained by differences in access and utilization of health care; as weight increases so do other comorbid conditions, making heavier men higher users of health care and perhaps more encouraged to be tested by their health care provider," said Richard Wender, MD, professor at Jefferson Medical College of Thomas Jefferson University and chair of Family and Community Medicine at Thomas Jefferson University Hospital, an author on the study.

A review of breast cancer screening research showed no correlation between weight and mammography use in women. In the three studies examined that stratified the obesity-screening relationship according to race, one study showed obesity corresponded with a decreased use of mammography in white women and increased use in their black counterparts. Two of the three studies found a positive association between obesity and mammography use in black women, while one study showed no effect.

Similarly, higher weight women, according to the team's analysis, were less likely to be screened for colorectal cancer (CRC), though the data made no reference to disparities in screening levels between races; research showed inconsistencies in the association between obesity and CRC screening in men. The studies available on CRC screening looked at a variety of testing options, making direct comparison difficult. On the whole, research showed that endoscopy, not fecal occult blood test (FOBT), was more likely influenced by weight status, specifically in women. Researchers surmise that this could be related to the fact that endoscopy is more invasive and therefore more difficult on obese patients relative to other screening tests.

Conclusions

Cultural differences among men, women, blacks and whites as well as socioeconomic factors such as insurance status and access to health care, which can be confounded with race/ethnicity and gender, may limit or grant access to certain cancer screenings.

"We hope to have built a more detailed picture of the relationship between obesity and cancer screening to inform efforts to identify and reduce disparities in cancer screening," said Fagan and Wender.

"Screening behaviors can vary by ethnicity/race and gender, but more research is needed to create a comprehensive understanding of obesity and cancer screening in race-gender subgroups such as white men, white women, black men and black women, accounting for the effects of the doctor-patient relationship, access to care and type of screening test."

Other authors on the study include Ronald E. Myers, PhD, Division of Population Science, Department of Medical Oncology, Thomas Jefferson University; and Nicholas Petrelli, MD, Helen F. Graham Cancer Center, Christiana Care Health System.