— Is Wi-fi dan­ger­ous?

Cosmos - - Contents - — AN­DREW MASTER­SON

THERE IS A STORY about an ex­per­i­ment by a group of Danish school­girls, in­volv­ing wa­ter­cress seeds in two ad­ja­cent rooms. In one room the seeds ger­mi­nate and thrive; in the other room, which has Wi-fi routers in it, the seeds fail to ger­mi­nate.

This is cited as proof that elec­tro­mag­netic fields (EMF) gen­er­ated by Wi-fi kill things.

We’ll come back to the wa­ter­cress in a minute, but first let’s ad­dress the big ques­tion to which it leads. Can Wi-fi tech­nol­ogy dam­age hu­mans?

Good science rarely, if ever, comes up with an unas­sail­able yes-or-no an­swer, and sci­en­tific in­ves­ti­ga­tion al­ways re­mains open to new data. So far, how­ever, af­ter scores of stud­ies, there is no un­con­tested ev­i­dence elec­tro­mag­netic fields cause any dam­age to hu­man tis­sue.

This didn’t ap­pear to be the case, how­ever, in 2011, when the World Health Or­gan­i­sa­tion’s In­ter­na­tional Agency for Re­search on Can­cer (IARC) an­nounced it had “clas­si­fied ra­diofre­quency elec­tro­mag­netic fields as pos­si­bly car­cino­genic to hu­mans based on an in­creased risk for glioma, a ma­lig­nant type of brain can­cer, as­so­ci­ated with mo­bile phone use”.

Head­lines based on this one sen­tence were star­tling. The agency’s own re­port, how­ever, noted ev­i­dence link­ing phone use and gliomas was “limited”, and ev­i­dence for links with any other kind of can­cer “in­ad­e­quate”. Even with these qual­i­fi­ca­tions, how­ever, some re­searchers sug­gested the IARC’S po­si­tion was based on poorly de­signed stud­ies.

The IARC po­si­tion was not sup­ported by a 2012 study pub­lished in the Bri­tish Med­i­cal Jour­nal. Re­searchers from the US Na­tional Can­cer In­sti­tute found no change in US glioma rates be­tween 1992 and 2008 – “a pe­riod co­in­cid­ing with a sub­stan­tial in­crease in mo­bile phone use from close to 0% to al­most 100%”. One of the main stud­ies used by the IARC had pre­dicted a 40% rise with wide­spread mo­bile phone use.

A 2011 Bri­tish study did find a slight in­crease in tem­po­ral lobe can­cers, but that trend be­gan in the 1970s, long be­fore mobiles and Wi-fi were in­vented. Over­all it found no in­crease in brain can­cers with the spread of mo­bile phones.

The largest in­ves­ti­ga­tion into the mat­ter – pub­lished in 2013, look­ing at al­most 80,000 mid­dle-aged Bri­tish women over seven years – found “mo­bile phone use was not as­so­ci­ated with in­creased in­ci­dence” of brain can­cers.

De­spite these (and many other) stud­ies, fears about Wi-fi and EMF con­tinue to flare up from time to time. Why might this be so? One clue comes from a study, pub­lished in Fe­bru­ary 2018, by sci­en­tists at the Na­tional Cheng Kung Univer­sity in Tai­wan. It found the num­ber of peo­ple pre­sent­ing to doc­tors with self-di­ag­nosed Emf-re­lated symp­toms rose and fell with me­dia re­ports about EMF dangers. In other words, the likely cause of EMF symp­toms was fear.

Now, briefly, back to the wa­ter­cress ex­per­i­ment. The mark of any good ex­per­i­ment is that other re­searchers can repli­cate it, right? In 2016 a Canadian sci­en­tist who is also a con­sul­tant to a com­pany that sells EMF ‘pro­tec­tion’ de­vices re­peated the work of the Danish school­girls. She re­ported the router­ex­posed cress grew just as well as the stuff in the other room.

IM­AGE Cris­tian Mi­hai Vela / Getty Im­ages

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