杏吧原创

IF YOU regularly turn to a search engine to find out whether, say, you should put ice on a twisted ankle, you鈥檙e far from alone. Sixty-one per cent of American adults seek out health advice online, according to a survey published last month by the .

Around a third of those surveyed admitted they changed their thinking about how they should treat a condition based on what they found online. Yet a growing body of evidence suggests that much online health information is unreliable.

鈥淢y overall impression is that the quality of health information varies wildly, almost ridiculously wildly,鈥� said , a pharmacologist at Nova Southeastern University in Fort Lauderdale, Florida. 鈥淚f [a website] is treated as an authoritative source, and there鈥檚 evidence that it isn鈥檛, then it鈥檚 potentially dangerous.鈥�

Several studies to be published in medical journals this year highlight the issue. Pia L贸pez-Jornet and Fabio Camacho-Alonso of the University of Murcia, Spain, found that information on oral cancers on the top websites gathered by Google and Yahoo searches was 鈥減oor鈥� (Oral Oncology, ). Among other things, the websites failed to attribute authorship, cite sources and report conflicts of interest. And a study by a team at the Charit茅 University Medical Centre in Berlin, Germany, of googled advice on how to deal with heartburn found that 鈥渢he evidence for most of the recommendations is weak to nonexistent鈥� (European Journal of Integrative Medicine, ).

While these and other studies examined dozens of websites, most agree that the site to watch is . Popular and easy to browse, the user-generated encyclopedia is the eighth most visited site on the internet, and the first stop for many seeking health information.

Wikipedia articles appear in the top 10 results for more than 70 per cent of medical queries in four different search engines, according to a study in this month鈥檚 Journal of the American Medical Informatics Association (). It also gets more hits than corresponding pages on the US National Library of Medicine鈥檚 MedlinePlus service.

This is worrying, and perhaps an indicator that some people鈥檚 search engine strategies may not be up to scratch. A 2002 study found that most searchers use only one term in their searches and rarely look past the first page of results 鈥� though internet users may have improved the way they search since then (BMJ, vol 324, p 573). More disconcerting is the percentage of doctors who turn to Wikipedia for medical information: 50 per cent, according to a report in April by US healthcare consultancy .

鈥淓ven more disconcerting is that 50 per cent of doctors turn to the user-generated Wikipedia for health info鈥�

How does Wikipedia fare as a medical reference? Its collaborative, user-generated philosophy generally means that errors are caught and corrected quickly. Several studies, including one examining health information, another probing articles on surgery, and one focusing on drugs, found the online encyclopedia to be almost entirely free of factual errors.

Better still, the articles improve significantly with time, according to a study Clauson published last December in the The Annals of Pharmacotherapy (vol 42, p 1814). 鈥淲ikipedia鈥檚 editing policy does work,鈥� he says.

But any Wikipedia page (beyond those locked to prevent vandalism) is vulnerable to malicious editing 鈥� and some drug firms have been caught removing negative information on their drugs from Wikipedia pages.

The site鈥檚 other major flaw is its incompleteness. Wikipedia was able to answer only 40 per cent of the drug questions Clauson asked of it. By contrast, the traditionally edited Medscape Drug Reference answered 82 per cent of questions. 鈥淚f there is missing safety information about a drug, that can be really detrimental,鈥� Clauson points out.

For example, Wikipedia鈥檚 makes no mention of complications when used alongside St John鈥檚 wort, the herbal supplement used to treat depression. Their potent interaction can cause the HIV therapy to fail.

On the other hand, the publicity Clauson鈥檚 research garnered has helped fix the shortcomings he highlighted. One error of omission 鈥� that pregnant women should avoid the painkiller Arthrotec 鈥� was fixed the same day on the study.

The medical community has taken note of Wikipedia鈥檚 success, and has made several attempts to replicate it. For instance, specialty-specific wikis (editable web pages) such as and can be edited only by doctors.

A more general medical wiki called , also written and vetted by medical professionals, launched in February. Medpedia was founded by San Francisco entrepreneur , who teamed up with several prominent medical schools and organisations to build a reliable medical database 鈥� with a social networking site at its heart. It includes non-encyclopedic resources such as a section for user Q&As and debates.

鈥淥ur goal is to be the place where physicians tell their patients to go educate themselves,鈥� Currier told New 杏吧原创. 鈥淓veryone can benefit from a more educated patient.鈥�

But it鈥檚 still always a good move to consult a professional before starting a treatment, he cautions. 鈥淎nything they see [on Medpedia] will be trustworthy stuff, but it鈥檚 not complete. Nobody is,鈥� he says.

It will take a long time for these smaller wikis to match the popularity of Wikipedia, however. 鈥淯ltimately, it will be easier to change the quality of information in Wikipedia than to change the search habits of an entire population,鈥� Clauson says.

The US National Institutes of Health is catching on. On 16 July, it hosted an event at its headquarters in Bethesda, Maryland, with the stated aim of teaching health professionals how to edit Wikipedia鈥檚 health pages and why they should think about doing so.

The Wikipedia of the future, it seems, looks set to become a far more reputable place.