There is currently some news going around that Covid lockdowns prematurely aged girls’ brains more than boys’

Adolescent girls who lived through Covid lockdowns experienced more rapid brain ageing than boys, according to data that suggests the social restrictions had a disproportionate impact on them.

MRI scans found evidence of premature brain ageing in both boys and girls, but girls’ brains appeared on average 4.2 years older than expected after lockdowns, compared with 1.4 years older for boys.

This certainly sounds like something we should be worried about, even if it is not clear what the effect of these differences are.

There are two things that should make you stop up, before getting two worried. It is the fact that the study is based on “MRI scans” and that it is about COVID political measures. MRI studies are rife with problems – as explained in Annual Research Review: Current limitations and future directions in MRI studies of child- and adult-onset developmental psychopathologie

The widespread use of magnetic resonance imaging (MRI) in the study of child- and adult-onset developmental psychopathologies has generated many investigations that have measured brain structure and function in vivo throughout development, often generating great excitement over our ability to visualize the living, developing brain using the attractive, even seductive images that these studies produce. Often lost in this excitement is the recognition that brain imaging generally, and MRI in particular, is simply a technology, one that does not fundamentally differ from any other technology, be it a blood test, a genotyping assay, a biochemical assay, or behavioral test. No technology alone can generate valid scientific findings. Rather, it is only technology coupled with a strong experimental design that can generate valid and reproducible findings that lead to new insights into the mechanisms of disease and therapeutic response

The subject the review focus on is not the one that the prematurely aged brains study fall under, but the same general problem exist.

And then there is the fact that the study is linked to COVID political measures. Any time this is the case, we have to stop up and be extra careful. There are a lot of biases related to this subject, both from the scientists and by the people reporting on the study.

Unsurprisingly this is also the case here. As epidemiologist Gideon Meyerowitz-Katz, the Health Nerd, explains:

Lockdowns Didn’t “Prematurely Age” Teen Girl’s Brains

Why the new viral study is extremely misleading

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The study in question is a neurological examination of teen brains. The researchers put a bunch of adolescents aged 9-17 into MRIs before the pandemic, and then looked at their brains again a few years later. They used this data to look at what had happened to the brains in the interim using a variety of statistical techniques.

The Health Nerd goes through the study, explaining the setup and limits of the study. Unsurprisingly, it is a small study, and it is hard to make broad conclusions based on it. And when it comes to the effect of lockdowns?

Which brings us to an interesting point – what does any of this have to do with lockdowns?

Simple answer, really: nothing. The study does not, in any way, examine the effects of lockdown on teen brains.

Rather, the study shows that teen girls’ brains after the pandemic were different to the expected trends from brains before the pandemic. This could be caused by many things. Maybe the virus itself, which can cause some changes to brain chemistry, is to blame. Perhaps it was the global disruption brought about by a novel pandemic. Maybe the girls were more vulnerable than boys to things like relatives dying of COVID-19. We have no idea, because the authors didn’t do anything to investigate these myriad explanations. They don’t even report that the children in the study were present in Washington State for the lockdowns, nor whether they experienced similar lockdown impacts (i.e. school closures).

To make any inferences about lockdowns, the authors would’ve had to find some control group who’d had a different exposure to their intervention. Perhaps MRIs from kids in Florida, which had different COVID-19 restrictions, or a longitudinal sample from before the pandemic. These would all be inadequate samples for one reason or another, but they would’ve at least given some insight into whether lockdowns were associated with the cortical thinning seen in the research. As it stands, the study tells us nothing at all.

So, this is a somewhat doubtful study, which doesn’t tell us what is claimed about the study. The claims however are not sensational reporting by the press, but directly made by the scientists:

You can’t just blame the media here – the authors put the word “lockdown” into their study. It’s the second word of the title of their paper. Despite the paper having nothing to do with lockdowns.

This is, in a word, bad. Bad science. Poorly thought-through. Inadequate in a very serious way.

The Health Nerd  explains how such a paper could be published in PNAS.