Ibuprofen linked to male infertility? It’s pure speculation

At least 10 news organizations rushed this week to cover a study asserting that the widely used painkiller ibuprofen might cause male infertility.

Among them:

CNN: Ibuprofen linked to male infertility, study says

USA Today: Ibuprofen use linked to male infertility, study finds

HealthDay/CBS News: Small study links ibuprofen with male infertility

The Guardian: Ibuprofen may increase risk of infertility issues in men, study suggests.

Too bad those eye-popping headlines don’t reflect what the research actually showed.

In fact, the study, based on a six-week clinical trial of 31 men and experiments on cells, wasn’t designed to detect a link between ibuprofen and an inability to father children.

The connection between ibuprofen and male infertility is a hypothesis offered up by the study authors in the abstract of the research paper, which was published in the Proceedings of the National Academy of Sciences. The link is also emphasized in a box summarizing the results which carries the heading “Significance.”

Coverage emphasizes ‘inflammatory speculation’

However, the results of the study itself have almost nothing to do with fertility, experts said.

“What the study did was to show that ibuprofen can have an effect on production of luteinizing hormone in the pituitary gland, which stimulates testosterone production,” said  HealthNewsReview.org contributor Karen Carlson, MD, in an email.

“It did not show any differences in testosterone production in men taking ibuprofen.  It did not examine sperm production or viability,” said Carlson, who’s director of Women’s Health Associates at Massachusetts General Hospital and associate professor of medicine at Harvard Medical School.

She added: “The coverage uniformly picked up on inflammatory speculation  — ‘it could happen’ – raising fears that have no scientific basis.”

Ajay Nangia, MD, a professor and vice-chair of urology at the University of Kansas Health System, has studied and written about the impact of medications on male fertility. He said the research is “very eloquent” basic science showing ibuprofen can affect hormone production, but it goes “way too far to say that it affects fertility in men.” He called that idea a “huge extrapolation” and “out of left field.”

“The media has jumped onto a statement and not onto the facts,” Nangia said.

Scary ‘what ifs’ lead; cautions appear lower down

News stories emphasized this scary hypothesis without informing readers that it was just a hypothesis.

CNN’s lead, for example, stated that ibuprofen has a “negative impact on the testicles of young men.”

The Telegraph wrote: “Taking ibuprofen for as little as two weeks may harm a man’s chance of becoming a father by hindering sperm production, a new study suggests.”

The fact that the observed hormonal changes in men who took ibuprofen were temporary and not proven to be harmful appeared lower in the coverage. Some stories also pointed out that any risks from ibuprofen would be associated with long-term use and that more research is needed, though the caveats didn’t always get prominent play.

Some journalists did show restraint. The Washington Post headlined its story more cautiously than most competitors: Ibuprofen appears to mess with male hormones: Should you be worried? It also said that ibuprofen is among a list of things researchers “suspect of potentially disrupting the body’s endocrine system.”

Technology website Ars Technica reported that the study is just “hinting that a common over-the-counter painkiller, ibuprofen, may be linked to a male reproductive disorder.”

Testosterone claims based on cell study — not human data

But in some cases stories falsely claimed the ibuprofen reduced testosterone production in the study subjects. In fact, the results section of the research paper states that “administration of ibuprofen did not result in any significant changes” in testosterone levels in the human subjects after 14 days or 44 days.

Reports of reduced testosterone production ignore those longer-term data in actual people; they appear to be based on a 48-hour test tube study where reproductive cells were exposed to ibuprofen. [Editor’s note: Requests for comment and clarification from the researchers had not received a response as of this writing; any reply will be posted as an addendum.]

Moreover, many stories labeled the young study subjects with a clinical condition called “compensated hypogonadism,” which has only been studied and defined in elderly men, Carlson said. For example, she said, “The Guardian describes this state as a ‘disorder’ when in fact there is little known about any health risks in this mild version of hypogonadism.”

The UK Express took scare tactics to the extreme in its story headlined with an “Ibuprofen warning” that stated the overuse of ibuprofen could lead to “full-blown hypogonadism – or low testosterone levels – which has been linked to premature death.”

Carlson added, “The consequences of declining male testosterone (seen with age) are not known with certainty; it is difficult to separate the effects of testosterone decline with age from that of aging per se.”

A recurring ‘spermapocalypse’

Media hysteria over threats to male reproductive health is not new.

Last fall HealthNewsReview.org contributor Alan Cassels chronicled “heavy-duty fear-mongering” in coverage of a study on falling sperm counts in men.

Just what’s driving changes in sperm count is unclear and hard to study, Cassels cautioned, citing this NPR quote from Allan Pacey, PhD, a professor of andrology at the University of Sheffield:

“There’s a real danger here that researchers publish papers like this, that are then reported irresponsibly, that then lead to people getting really paranoid about what may or may not be happening.”

Pacey warned against media reports of a “spermapocalypse.”

Extrapolation from the evidence has resulted in male fertility scares about cell phones, laptops, and vitamin D deficiency, Nangia said. Now with ibuprofen, “men who see this in their news feeds are now going to wonder if it affects their sperm.”

To avert the next spermapocalypse, news organizations should hew to what the evidence shows.