A thought-provoking perspective article in the NEJM 2012; 367: 1677-79 makes the argument that public health organizations/health professionals should be providing facts to inform people and not try to persuade or dissuade  them from screening for health conditions.

Examples of persuasion:

• “The early warning signs of colon cancer: You feel great. You have a healthy appetite. You’re only 50.” (ad from New York Times Magazine from Memorial Sloan-Kettering Cancer Center)
• “If you haven’t had a mammogram, you need more than your breasts examined.” (from American Cancer Society, 1970s)

The problem with persuasion messages is that they are ‘stripped of useful facts’ that indicate that screening can have harms as well as benefits.

For colon cancer, most 50-year-olds who feel great will not develop colon cancer.  The National Cancer Institute estimates that a 50-year-old has a 6 in 1000 chance of developing colon cancer in the next 10 years; the chance of death from colon cancer in that period 2 in 1000.  The advantages of colon screening would be to reduce that risk further: 67% with colonoscopy and 26% with sigmoidoscopy.  Screening, however, could result in bleeding, anesthetic complications, or perforation.

The tactics of persuasion rely on making people feel vulnerable and offering them hope.  Informed decisions allow appropriate expectations about the true benefits relative to harm.