What You Believe Can Kill You

Reading time: 4 – 6 minutes

The Washington Post published a story yesterday stating that Personal Health Beliefs are Largely Hit and Myth. The story discusses the results of an American Cancer Society (ACS) study released last week, which will be published in the September 1st issue of the journal Cancer.

The study assessed the prevalence and sociodemographic correlates of scientifically unsubstantiated beliefs about cancer risk, finding that [1]:

… beliefs in several scientifically unsubstantiated cancer risk statements are relatively common among the participants in this study, and that the prevalence of such beliefs varies by certain sociodemographic characteristics.

Men were more likely to endorse scientifically unsubstantiated cancer risk beliefs than women. Other characteristics associated with lower health literacy included non-white race, Hispanic ethnicity, income below $30,000 and less than a high school education. Surprisingly, those people who considered themselves “somewhat informed” or “not very informed” about cancer, compared to those who considered themselves “very informed”, were less likely to agree with unsubstantiated cancer risk beliefs. The authors state that this result is consistent with previous research [2], demonstrating that people tend to overrate their own abilities and reach judgements with too much confidence. Remarkably, over two-thirds of those people surveyed believe that the risk of dying from cancer in the U.S. is increasing.

This simply is not true.

Back in January I wrote about the decrease in annual U.S. cancer deaths when the 2007 cancer statistics were published. The age-standardized cancer death rate has been decreasing since the early 1990s [3,4].

The ACS study reminded me of anther investigation published in May of this year that examined the sociodemographic correlates of fatalistic beliefs regarding cancer prevention [5]. Said another way, “what personal characteristics correlate with the belief that cancer is predetermined and inevitable?”

The study found the following with respect to fatalistic beliefs about cancer prevention:

  • Nearly half of respondents agreed that “It seems like almost everything causes cancer.”
  • Over one-quarter of respondents agreed that “There’s not much people can do to lower their chances of getting cancer.”
  • A whopping 72% of respondents agreed that “There are so many recommendations about preventing cancer, it’s hard to know which ones to follow.”

The results were similar to the ACS study mentioned above, that is, that fatalistic beliefs about cancer are stronger among less educated Americans. A notable difference however in the results is that, when controlling for socioeconomic status (with the exception of Spanish-speaking Hispanics), the beliefs are either weaker or equivalent among African Americans and Hispanics compared with Whites. I must point out that these results are inconsistent with earlier investigations as well as the recent ACS study. The study’s relatively low response rate (34.5%) may be responsible for this inconsistency.

Family cancer history was linked to a stronger belief that “everything causes cancer”, which suggests a proximal cancer experience that raises perceived risk. Unexplainably, being married or living as married was associated with greater agreement of two of the three fatalistic beliefs.

These results are a cause for concern as fatalistic beliefs are associated with people NOT engaging in cancer prevention behaviors, including regular exercise, not smoking, and fruit and vegetable consumption. Individual beliefs in several scientifically unsubstantiated cancer risk statements may influence actual health-related behaviors and adherence to cancer screening guidelines. Indeed, although a few years ago the ACS estimated that half of all men and one third of women may develop some type of cancer in their lifetime [6], as much as 70% of all cancers are preventable through diet and lifestyle.

The take-home message? There is a great deal of misinformation and scientifically unsubstantiated health beliefs in the world today. Be extremely critical of what you read and hear. Demand to see the scientific data and base your beliefs on the evidence.


  1. Stein et al. Prevalence and sociodemographic correlates of beliefs regarding cancer risks. Cancer. 2007 Jul 26; [Epub ahead of print].
    View abstract
  2. Dunning et al. Flawed self-assessment. Implications for health, education, and the workplace. PsycholSci Public Interest. 2004; 5: 69-106.
  3. Jemal et al. Cancer statistics, 2007. CA Cancer J Clin. 2007 Jan-Feb;57(1):43-66.
    View abstract
  4. Ries et al. SEER Cancer Statistics Review, 1975-2003. National Cancer Institute, Bethesda, Md. Updated 2006.
  5. Niederdeppe and Levy. Fatalistic beliefs about cancer prevention and three prevention behaviors. Cancer Epidemiol Biomarkers Prev. 2007 May;16(5):998-1003.
    View abstract
  6. Cancer Facts & Figures 2005. American Cancer Society. Atlanta, Ga. 2004.
About the Author

Walter Jessen, Ph.D. is a Data Scientist, Digital Biologist, and Knowledge Engineer. His primary focus is to build and support expert systems, including AI (artificial intelligence) and user-generated platforms, and to identify and develop methods to capture, organize, integrate, and make accessible company knowledge. His research interests include disease biology modeling and biomarker identification. He is also a Principal at Highlight Health Media, which publishes Highlight HEALTH, and lead writer at Highlight HEALTH.