About half of American adults believe in at least one medical conspiracy theory, according to new survey results.
Some conspiracy theories have much more traction than others, however, they report in the American Medical Association journal JAMA Internal Medicine.
For example, three times as many people believe U.S. regulators prevent people from getting natural cures as believe that a U.S. spy agency infected a large number of African-Americans with the human immunodeficiency virus (HIV).
J. Eric Oliver, the study's lead author from University of Chicago, said people may believe in conspiracy theories because they're easier to understand than complex medical information. "Science in general - medicine in particular - is complicated and cognitively challenging because you have to carry around a lot of uncertainty," Oliver said.
Oliver and a colleague used data from 1,351 adults who answered an online survey about six popular medical conspiracy theories, so it's not quite scientific, but still interesting.
The theories: That the government knows cell phones cause cancer but does nothing about it, that genetically modified organisms are being used to shrink the world's population, that routine vaccinations cause autism and that water fluoridation is a way for companies to dump dangerous chemicals into the environment.
Some 49 percent of the survey participants agreed with at least one of the ideas.
People who believed in conspiracies were more likely to use alternative medicine and to avoid traditional medicine.
“For people who don't have a lot of education, it's relatively easy to reject the scientific way of thinking about things,” Oliver says.