A study linked poor posture from cellphone use to hornlike protuberances on the back of millennials' skulls.

But some members of the academic community say the study is flawed, and one expert said the researchers did not provide an adequate table of results.

What's more, one of the study authors owns an online store that sells posture-correcting pillows.

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Could our cellphone use be causing us to grow horns?

That question has been circulating over the last couple of weeks, after this headline appeared in The Washington Post: "Horns are growing on young people's skulls. Phone use is to blame, research suggests."

The academic study on which The Post's story is based came out in February 2018 in the journal Scientific Reports. It suggested that bony growths called external occipital protuberances — which are found in the middle of the back of skull, above where our neck muscles attach — are popping up more often than expected in people between the ages of 18 and 30.

The study authors suggested that these protuberances might arise because of sustained bad posture, which is "associated with the emergence and extensive use of hand-held contemporary technologies, such as smartphones and tablets."

However, experts are taking umbrage at the claim, saying the study leaves much to be desired in terms of data and research methodology.

"The study has a number of considerable flaws," William Harcourt-Smith, a physical anthropologist from Lehman College in New York, told Business Insider. "The way the media are using the word 'horns' is appalling."

David Shahar, the lead author of the study, told Business Insider the term "horn" came from the media and "doesn't appear in our research." But he told The Washington Post: "You may say [the protuberance] looks like a bird's beak, a horn, a hook."

Semantics aside, here's why you shouldn't worry about growing bumps on the back of your head.

These growths aren't anything new

In the February 2018 paper, Shahar and his coauthor, Mark Sayers, referred to the bony growth as "a degenerative musculoskeletal feature," a term typically associated with deterioration and loss of function.

But these protuberances are fairly common among older people — and harmless, for the most part.

"Men have it more often than women, so much so that this is one of several traits that help forensic scientists establish whether a skeleton belonged to a male or female individual," the anthropologist John Hawks wrote in an article.

Given that external occipital protuberances (EOPs) are present in most people as a very small bump, Shahar told Business Insider, they considered the bump to be enlarged only "if the 'bump' was over 10 millimeters."

The duo published three papers about enlarged EOPs, which they shortened to EEOPs, in younger people between 2016 and 2018. The paper at the center of the recent hubbub analyzed X-ray images taken of 1,200 people from the side (in order to see the curvature of the neck and the back of the skull).

But it turns out that those 1,200 patients weren't a random, representative subset of the population; rather, the patients had all already been going to a chiropractor for help.

What's more, they were all patients from Shahar's own chiropractic clinic in Queensland, Australia, according to Quartz.

There could be other possible explanations for these bumps

In their February 2018 paper, the researchers reported that 35% of the young men and more than 40% of the young women they studied under the age of 30 had one such protuberance, which could be more than an inch in size.

Less than 15% of people between the ages of 30 and 50 had the same bony growth, they found.

The authors seemed to suggest that these growths could arise because when we look down at our phones, we shift our heads' weight from over the spine to the neck muscles. It's similar to the way pressure from a high-heeled shoe can cause a bone spur on the backs of one's feet.

In a world in which parents are concerned about screen time and app developers use psychological tricks to keep us looking at our smartphones, news that humans are physically changing because of cellphones might not seem far from the realm of possibility.

However, Shahar said he and his colleague "have not ever drawn direct links between the presence of EEOP[s] and mobile technology use."

Instead, he said, "we have suggested that the cause appears to be a mechanical one," drawing links between the presence of these enlarged bony growths and sustained postures in which the neck is craned forward — a position that's "often associated with the use of mobile technologies."

Shahar and Sayers also said in their paper that there could many other possible explanations for these bumps, including poor posture "while sitting, standing, or sleeping," "bike riding using drop hand-bars," or "sleeping supine with a high pillow."

Shahar owns a company that sells posture-correcting pillows

Shahar might have a stake in encouraging the general public up to worry about their posture: He owns a company called Dr. Posture, which sells posture-correction products. The website markets a trademarked $195 thoracic pillow to correct head posture.

Shahar failed to report this business venture in the "competing interests" section of his and Sayers' February 2018 paper.

He told Quartz that he has "been largely inactive in that front over the years of my research, and this research does not discuss any particularly related intervention methods."

However, the 2018 paper does suggest that "the mitigation of poor postural habit through prevention intervention may be prudent."

Nature Research, which publishes Scientific Reports and is considered one of the most reputable publishers of scientific literature, ensures that its studies are peer reviewed by two reviewers, as the publisher told PBS NewsHour.

"We are looking into issues regarding this paper and we will take action where appropriate," a spokesperson told PBS NewsHour.

Horns aren't made of bone

Hawks also takes issue with the characterization of these protuberances as horns.

"Horns," he wrote, "are made of keratin, the same stuff as fingernails."

Equating bony extensions with keratinous outgrowths could be a step too far, Hawks said on his website.

"Personally, I think scientists have to be extra alert to make sure that they don't use words that lead to misunderstandings," he told Business Insider.

Horns are made of keratin. Chung Sung-Jun/Getty

What's more, Hawks said, one of the figures in the February 2018 study data doesn't align with a number that the authors wrote in the text. In the study, one figure indicates that more than 40% of females and 35% of males under the age of 30 had a protuberance. But the text also says males are "5.48 times more likely to have [a protuberance] than females."

In an email, Shahar clarified that men are more likely to have bumps then women overall, but in the group of people in the study, 40% of women under 30 had the bumps, while only 35% of men in the same age group did.

The authors did not offer a table of results, so it's impossible to know exactly how many protuberances the researchers observed in their X-rays.

The study didn't measure cellphone use

David J. Langer, the chairman of neurosurgery at Lenox Hill Hospital in New York, also expressed skepticism about the study to The New York Times.

"It doesn't make a bit of sense to me," Langer said.

He added that folks who spend an abnormal amount of time looking down with a bent neck (like surgeons) are known to have disc problems, not changes in their skulls.

"You're more likely to get degenerative disc disease or misalignment in your neck than a bone spur growing out of your skull," Langer told The Times. "I haven't seen any of these, and I do a lot of X-rays. I hate being a naysayer off the bat, but it seems a little bit far-fetched."

There's one other nagging issue with the 2018 study: The researchers did not measure the cellphone use of the 1,200 people whose X-rays they studied.

"They're arguing that young people are spending a lot of time hunched over their laptops and their phones," Jeff Goldsmith, a biostatistician at Columbia University who was not involved in the study, told PBS NewsHour. "But they don't actually have any data about screen time, their [subjects'] typical posture or about any of the things that might give you a way to evaluate that hypothesis."

That means that the authors' suggestion that cellphone use might be causing the poor posture that gave rise to these protuberances is based solely on the conjecture that people between 18 and 30 are on their phones more than older generations.

Shahar acknowledged that the study was not a randomized controlled trial, saying that such a study "would need to be performed over 10 to 20 years and would require some quite invasive techniques."

It's possible that Shahar and Sayers' claims about the relationship between bad posture and protuberances are true. But before suggesting that cellphone use could cause bone growths, it would make sense to measure both the input and the result.

"We are not against these modern technologies (quite the opposite actually), rather we are trying to highlight that sustained poor posture comes at a price," Shahar said in an email.