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MONDAY, July 8 (HealthDay News) -- Searching the Internet for medical information may leave behind a lucrative trail for profit-makers, a new study says.
When patients go online to look up a specific condition, the websites often sell that search information to companies that target ads to individual users. Or maybe they'll use the secretly obtained knowledge for something more sinister, the study contended.
"We should be a little worried," said study author Dr. Marco Huesch, an assistant professor at the Sol Price School of Public Policy at the University of Southern California, in Los Angeles.
"The Internet has allowed us to access lots of free content, but as the saying goes, 'If you're not a paying customer for a website, then you're the product,' " Huesch said.
The only safe free medical sites appear to be government-sponsored, according to a research letter published July 8 in the journal JAMA Internal Medicine.
The third parties doing this tracking are usually companies that sell data to advertisers, marketers and the consumer goods-and-services industry.
"They are not insurance companies or drug companies, but clearly their customers and clients would be," Huesch said.
It's possible they aggregate medical-site users with dozens, hundreds or thousands of other people with similar interests and demographics, instead of keeping track of individuals, "but that's up to them," he added.
Until privacy legislation is strengthened, patients and consumers need to be careful about potential loss of anonymity and breaches of confidentiality while online, Huesch said.
Dr. David Katz, director of the Yale University Prevention Research Center, said this study is a reminder that with great new power comes great exposure.
"The Internet is a window that works both ways," Katz said. "We can look out at the world through it, but the world is looking back. Sites devoted to health information are no exception."
This is not, however, a reason to avoid health sites, which can be enormously useful and empowering, he said.
Huesch used readily available software last December and January to detect whether search information was being passed from 20 popular health-related websites to third parties.
All 20 sites passed data to at least one third party, and the average was six or seven. Thirteen sites had one or more tracking elements, the study found.
No tracking was found on doctor-oriented sites tied to professional groups, Huesch said.
Five of the 13 sites that tracked data also linked to social media, and searches were leaked to third parties through this link in seven websites. Facebook's "Like" button is an example.
No leaking of data was detected on U.S. government sites, such as the National Institutes of Health and the Food and Drug Administration, or four of the five physician-oriented sites, Huesch said.
The free privacy tools he used are Ghostery (evidon.com) and DoNotTrackMe (abine.com). However, he added, "I'm not sure whether they can block everything, and I'm not sure whether mobile smartphone browsing can be protected similarly."
Whether the leaked information was actually used by third parties wasn't possible to determine. But Huesch and others say you should assume the information you reveal on free medical-related sites is not private.
Until it's possible to blend universal access with privacy protection, Katz said, it is best to think that much of what you do online is being done in front of a crowd.
For more information on Internet security, visit the Center for Democracy and Technology.