When Kim Kardashian posted on Instagram^[1] about having had a full-body MRI^[2], she enthused that the test can be “life saving”, detecting diseases in the earliest stages before symptoms arise.

What Kardashian neglected to say was there’s no evidence this expensive scan can bring benefits for healthy people^[3]. She also didn’t mention it can carry harms including unnecessary diagnoses^[4] and inappropriate treatments.

With this post in mind, we wanted to explore what influencers are telling us about medical tests.

In a new study^[5] published today in JAMA Network Open, we analysed nearly 1,000 Instagram and TikTok posts about five popular medical tests which can all do more harm than good to healthy people, including the full-body MRI scan.

We found the overwhelming majority of these posts were utterly misleading.

5 controversial tests

Before we get into the details of what we found, a bit about the five tests^[6] included in our study.

While these tests can be valuable to some, all five carry the risk of overdiagnosis for generally healthy people. Overdiagnosis^[7] is the diagnosis of a condition which would have never caused symptoms or problems. Overdiagnosis leads to overtreatment, which can cause unnecessary side effects and stress for the person, and wasted resources for the health system.

As an example, estimates suggest 29,000 cancers a year are overdiagnosed^[8] in Australia alone.

Overdiagnosis is a global problem, and it’s driven in part by healthy people having tests like these. Often, they’re promoted under the guise of early screening, as a way to “take control” of your health. But most healthy people simply don’t need them.

These are the five tests we looked at:

The full-body MRI scan claims to test for up to 500 conditions, including cancer. Yet there is no proven benefit of the scan for healthy people, and a real risk of unnecessary treatment from “false alarm^[9]” diagnoses.

The “egg timer” test (technically known as the AMH, or anti-mullarian hormone test) is often falsely promoted as a fertility test for healthy women. While it may be beneficial for women within a fertility clinic setting, it cannot reliably predict the chance of a woman conceiving^[10], or menopause starting^[11]. However, low results can increase fear and anxiety^[12], and lead to unnecessary and expensive fertility treatments^[13].

Multi-cancer early detection blood tests are being heavily marketed as the “holy grail of cancer detection”, with claims they can screen for more than 50 cancers. In reality, clinical trials are still a long way from finished. There’s no good evidence yet^[14] that the benefits will outweigh the harms of unnecessary cancer diagnoses.

The gut microbiome test of your stool promises “wellness” via early detection of many conditions, from flatulence to depression, again without good evidence of benefit^[15]. There’s also concern that test results can lead to wasted resources^[16].

Testosterone testing in healthy men is not supported by any high-quality evidence, with concerns direct-to-consumer advertising leads men to get tested and take testosterone replacement therapy unnecessarily^[17]. Use of testosterone replacement therapy carries its own risk of potential harms with the long-term safety in relation to heart disease and mortality still largely unknown^[18].

Multi-cancer early detection blood tests are heavily marketed. Yuri A/Shutterstock^[19]

What we found

Together with an international group of health researchers, we analysed 982 posts pertaining to the above tests from across Instagram and TikTok. The posts we looked at came from influencers and account holders with at least 1,000 followers, some with a few million followers. In total, the creators of the posts we included had close to 200 million followers.

Even discounting the bots, that’s a massive amount of influence (and likely doesn’t reflect their actual reach to non-followers too).

The vast majority of posts were misleading, failing to even mention the possibility of harm arising from taking one of these tests. We found:

• 87% of posts mentioned test benefits, while only 15% mentioned potential harms

• only 6% of posts mentioned the risk of overdiagnosis

• only 6% of posts discussed any scientific evidence, while 34% of posts used personal stories to promote the test

• 68% of influencers and account holders had financial interests in promoting the test (for example, a partnership, collaboration, sponsorship or selling for their own profit in some way).

Further analysis revealed medical doctors were slightly more balanced in their posts. They were more likely to mention the harms of the test, and less likely to have a strongly promotional tone.

The vast majority of posts we looked at were misleading. DimaBerlin/Shutterstock^[20]

As all studies do, ours had some limitations. For example, we didn’t analyse comments connected to posts. These may give further insights into the information being provided about these tests, and how social media users perceive them.

Nonetheless, our findings add to the growing body of evidence^[21] showing misleading medical information is widespread on social media.

What can we do about it?

Experts have proposed a range of solutions including pre-bunking strategies^[22], which means proactively educating the public about common misinformation techniques.

However, solutions like these often place responsibility on the individual. And with all the information on social media to navigate, that’s a big ask, even for people with adequate health literacy.

What’s urgently needed is stronger regulation to prevent misleading information being created and shared in the first place. This is especially important given social media platforms including Instagram are moving away from fact-checking^[23].

In the meantime, remember that if information about medical tests promoted by influencers sounds too good to be true, it probably is.

References

1. ^{^} posted on Instagram (www.instagram.com)
2. ^{^} full-body MRI (theconversation.com)
3. ^{^} healthy people (onlinelibrary.wiley.com)
4. ^{^} unnecessary diagnoses (link.springer.com)
5. ^{^} new study (jamanetwork.com)
6. ^{^} the five tests (www.researchprotocols.org)
7. ^{^} Overdiagnosis (theconversation.com)
8. ^{^} 29,000 cancers a year are overdiagnosed (theconversation.com)
9. ^{^} false alarm (onlinelibrary.wiley.com)
10. ^{^} chance of a woman conceiving (jamanetwork.com)
11. ^{^} menopause starting (academic.oup.com)
12. ^{^} increase fear and anxiety (www.tandfonline.com)
13. ^{^} fertility treatments (pubmed.ncbi.nlm.nih.gov)
14. ^{^} no good evidence yet (www.bmj.com)
15. ^{^} without good evidence of benefit (www.nytimes.com)
16. ^{^} wasted resources (www.degruyter.com)
17. ^{^} leads men to get tested and take testosterone replacement therapy unnecessarily (jamanetwork.com)
18. ^{^} still largely unknown (www.sciencedirect.com)
19. ^{^} Yuri A/Shutterstock (www.shutterstock.com)
20. ^{^} DimaBerlin/Shutterstock (www.shutterstock.com)
21. ^{^} growing body of evidence (pubmed.ncbi.nlm.nih.gov)
22. ^{^} pre-bunking strategies (theconversation.com)
23. ^{^} moving away from fact-checking (theconversation.com)