Study: The More Popular the Health-Related YouTube Video, the More Likely It Is to Be Inaccurate

Laptop with heart monitor on screen, and stethoscope laying over keyboard

It should come as no surprise that not all information on the internet is reliable. It’s a largely unregulated wild, wild west that allows for anyone to put up any content they wish to. Which can be a particular problem when it comes to health-related content.

Researchers with New York UniversityMonash University in Australia, Royal College of Surgeons in Dublin, Ireland, Louisiana State University, and the Prostate Cancer Center in Warsaw, Poland, recently conducted a study that analyzed prostate cancer-related videos on YouTube. They published their research, “Dissemination of Misinformative and Biased Information about Prostate Cancer on YouTube,” in the journal European Urology.

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They searched YouTube for “prostate cancer screening” and “prostate cancer treatment,” and scored the first 75 hits for each search phrase. They then used validated scales to evaluate the contents of the videos. That included determining whether the video was in favor of new technology, recommended unproven treatments, showed commercial bias or accurately described the risks and benefits of the recommendations.

They found many things, including that biased or inaccurate videos had more than 6.3 million views. And approximately 77 percent of the videos contained incorrect information, 27 percent had some commercial bias towards expensive and untested treatments, and 19 percent recommended unproven alternative treatments.

And around 75 percent of the videos talked about the benefits of treatments, but about half didn’t mention any risks or side effects.

In a startling example of confirmation bias—where you tend to interpret new data as a confirmation of your existing beliefs—the researchers found that the higher the number of views, “likes” and “thumbs up” ratings a video received, the worse the information quality generally was. For example, one video that had been viewed by more than 300,000 people promoted the injection of a Chinese herb into the prostate—a treatment that has no scientific evidence supporting it.

Johns Hopkins Medicine has a reference guide titled, “Reliable Cancer Information on the Internet.” In it, they note that a Google search for “cancer” produces over 38,300,000 results. As a way to sift through all those sites looking for reliable health information, the guide suggests four points to consider:

  1. Accuracy. In order to determine that, they suggest checking multiple sources for the same information.
  2. Authority. The most reliable websites typically end in .org, .gov or .edu. Verify whether the information was written by healthcare professionals, such as doctors or nurses.
  3. Bias. In short, follow the money. Who’s paying for the website? That’s not necessarily the most reliable way to exclude data, however. For example, pharmaceutical companies usually have dedicated product pages for their approved drugs that provide information for both physicians and patients.
  4. Date. When was the site updated last? Information older than three years is suspect.

And the reference guide suggests the first place to search for cancer information is the National Cancer Institute (NCI) at

The American Cancer Society has a similar webpage, that suggests similar questions. They too suggest starting with the NCI.

Another question they suggest asking is: “What’s the purpose or mission of this website?”

Sometimes you can tell based on who runs the site—for example, NCI or the American Cancer Society are focused on providing reliable information about cancer. They’re not trying to sell you something. The American Cancer Society notes, “Websites designed to promote or sell products may be more likely to have slanted or inaccurate health information than sites designed to simply provide information. Some sites try to do both, but you should look at these carefully, too. Remember that if a website’s main purpose is to sell products, it will only contain the information the seller wants you to read.”

“Yes, but you pointed out that drug companies’ product pages are reliable.”

Two things to consider there. First, is the information aimed at physicians? Usually, drug company product pages have information targeting physicians and a separate page targeting consumers. 

Second, consider if the drug—for U.S. readers, at least—is approved for use in the U.S. by the Food and Drug Administration (FDA).

One area of significant concern is the prevalence of companies outside the U.S. selling drugs or healthcare products online. This is an area that falls under the law enforcement roles of the FDA. There have been numerous cases of unsafe drugs being sold online, and the FDA, in conjunction with other law enforcement agencies has worked to shut many of them down. However, it’s an ongoing process. In August 2018, the FDA warned four online networks that operated 21 websites selling opioids online. The warnings indicated they were “illegally marketing potentially dangerous, unapproved, and misbranded versions of opioid medications, including tramadol. The warning letters issued by the FDA to each of the networks state that they must immediately stop illegally selling these products to American consumers.”

And, of course, it’s exacerbated by problems with healthcare coverage and the often high prices of branded drugs.

The American Cancer Society also lists six warning signs, as specified by the U.S. Federal Trade Commission (FTC), that a website may be selling snake oil instead of reliable products or information.

  1. Claims of a “scientific breakthrough,” “miraculous cure,” or “ancient remedy.”
  2. That the product can cure a broad range of diseases.
  3. Seemingly miraculous results not linked to scientific data, often anecdotal.
  4. Claims that they’re the only source for the product and/or you must pay in advance.
  5. A “money-back” guarantee.
  6. A lack of specific website information, such as the company’s name, street address, phone number and other contact information.

They note, “Problems in any of these areas should raise a red flag—a warning—to the user that the site may contain information that’s not based on careful science and cannot be trusted. This may be especially important when looking at sites promoting complementary or alternative cancer treatments.”

When in doubt, consult with your physician. 

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