Whether Coke or colonoscopies, celebrities endorse practically everything. Celebrity endorsements of cancer screening tests can affect people's decisions about getting screened—and that's not all good, warn the authors of a new study.

What the researchers wanted to know: What percentage of Americans have heard or seen celebrities telling them to get cancer screening, and how does that appear to influence their decision-making about whether to get screened?

What they did: From December 2001 to July 2002, interviewers called random phone numbers and talked to 500 adults who hadn't had cancer but were among categories for which screening is often recommended—women ages 40 and up and men ages 50 and up. Depending on which tests might be recommended for their sex and age, they were asked, "Have you ever seen or heard celebrities like Katie Couric talk about getting a sigmoidoscopy or colonoscopy?" and similar questions about Nancy Reagan and Rosie O'Donnell (mammograms) or Norman Schwarzkopf (prostate-specific antigen, or psa, tests). They were also asked whether seeing or hearing those messages had made them more likely to have the test. The surveys were part of a larger study on attitudes about cancer screening.

What they found: Most people had encountered celebrity endorsements of screening tests. Nearly three quarters of women 40 and up had heard or seen celebrities talk about mammograms, almost two thirds of men ages 50 or older had heard about psa testing from celebrities, and just over half of adults ages 50 or older had heard about sigmoidoscopies or colonoscopies. In all three of those groups, most of the people said that what they'd heard from celebrities had no effect on their plans (or lack of plans) to have the cancer test in question. But a substantial portion did say the celebrity endorsement made them more likely to have the test: 25 percent for mammograms, 31 percent for psa tests, and 37 percent for sigmoidoscopies or colonoscopies.

What the study means to you: Cancer screening tests like mammograms and colonoscopies aren't without risks, say the researchers. The chance of finding colon cancer with a colonoscopy, for example, should be weighed against the risk of a false alarm, the cost of the test, the risk of injuring the intestine, and the discomfort of the test. So cancer screening is definitely something to discuss with your doctor. The researchers say that simple, one-sided messages delivered by celebrities are better suited to simple, one-sided issues like avoiding tobacco than to complex issues like cancer screening.

Caveats: Everyone in the survey was of an age for which the screening tests are often recommended anyway; it would be interesting to know whether celebrity endorsements are making, say, 25-year-olds think they need colonoscopies and psa tests. Also, the researchers didn't say whether people who'd heard celebrities endorse a test were more likely to actually have the test done—just whether the celeb seemed to influence their decision.

Find out more: The American Cancer Society gives guidelines on screening for breast cancer, colorectal cancer, and other common screening tests.

The Centers for Disease Control and Prevention has information about the uncertainties of the psa test.

Read the article: Larson, R.J., et al. "Celebrity Endorsements of Cancer Screening." Journal of the National Cancer Institute. May 4, 2005, Vol. 97, No. 9, pp. 693–695.

Abstract online: http://jncicancerspectrum.oupjournals.org