Star power entices wrong people

When "Today Show" host Katie Couric underwent a televised virtual colonoscopy in 2000, she probably didn't expect that her endorsement would have an influence on the wrong people.

Numerous people younger than 50 responded to Couric's call for colon screening, reflecting her audience's demographics, according to a University of Michigan study. National guidelines recommend the test every 10 years for people 50 and older.

The public's blind trust in celebrity testimony contravenes standards that call for balanced dialogue, said Dr. Robin J. Larson, an instructor of medicine at Dartmouth Medical School.

Larson found that one-quarter of women and two-thirds of men surveyed were more likely to get a mammogram and a colonoscopy, respectively, because of celebrity endorsement (J Natl Cancer Inst 2005;97[9]: 693-695).

"Do these messages influence people most likely to benefit, or do they influence people for whom the benefits are not thought to outweigh the harms, such as Katie Couric, who was not of screening age or high risk?" Larson asked.