F. Perry Wilson, MD

Check out the incidence of colorectal cancers among 45-49 year old's over time.
Scary, right?
This week, I wrote about a trio of papers in @jamacurrent trying to explain this phenomonon.
Full details @medscape here: www.medscape.com/viewarticle/...

For more discussion and a deeper dive into this study, please check out my column here on @medscape: buff.ly/7PgnJmv

Scientists are starting to decode a new language - one that we had thought we were incapable of understanding - the language of smells. Somewhere deep in the recesses of our brains, there is still some part of us that responds to these invisible, oft-imperceptible signals. /🧵

They were then asked to rate how attractive women were based on pictures of their faces. For women who were rated highly attractive overall, the scent didn't matter much. But for those rated less attractive, their scores improved significantly with the ovulation cocktail.

The men weren't ask about scents. Instead, they were asked about mood. And when exposed to the ovulation cocktail they reported significantly less hostility.
Music hath charms to soothe the savage beast? Nonsense. (E)geranyl-acetone does.

This was tricky. They had the guys go into a room wearing a headset with a microphone. Unbeknownst to the men, but knownst to us, the cover on the mic had been dosed with either nothing, the ovulation cocktail, armpit odor, or armpit+ovulation cocktail.

Still, one can imagine that this combination of smells might be attractive. The researchers went further though, synthesizing an "ovulation cocktail" of just these three chemicals to see how men would react to them...

Three compounds stood out.
(E) geranyl-acetone, tetradecanoic acid, and (Z)9-hexadecanoic acid.
Pretty fascinating. The first has some of that citrus / floral aroma. The second is notably secreted in breast milk (and induces a suckling reflex in babies!). The third is odorless.

But the scientists didn't stop there. They used mass spec to analyze nearly 100 different volatile compounds in these samples to identify those most significantly elevated during ovulation.

Getting descriptive, the ovulation scents were described as more green/grassy, floral, citrus and less musty / vinegary.

Primary results are here. You can see that no smell was more pleasant than an odor-free control, but the samples collected during ovulation were rated significantly more "pleasant".

Researchers had 21 women volunteers act as scent donors. They placed a special silicone pad under their armpits during the fours phases of the menstrual cycle. 21 men, blinded to that information, rated the smells on these pads.

I'm referring to this paper, appearing in iScience, by Ohgi et al.
www.cell.com/iscience/ful...

Thanks to a clever use of mass spectroscopy, scientists seem to have uncovered the actual "scent of a woman" - a cocktail of compounds, released during ovulation, that actually changes men's behavior. Brief thread:

For more on this please check out my column on @medscape: www.medscape.com/viewarticle/...
/thread

The question is whether this is reversible or not. Like, now that we are all back at work and integrating with society, can our brains go younger? Here's hoping. But if the pandemic-induced gray in my hair is any indication, that horse might be out of the barn.

The implication here is that it was the PANDEMIC that aged our brains, not necessarily the virus. It's like the social isolation, the stress, the loss of cognitively stimulating activities (like work) sort of atrophied us.

You might think that covid INFECTION made the difference here, but the data doesn't really show that. 134 people were infected between their two scans compared to 298 who were not (yet) infected. And their brains aged similarly.

Now let's add the pandemic group. You can see that the distribution is shifted - by 5.5 months. Hence the scary headline. Of course, that's an average. Some people's brains got older than that, some younger.

The BAG of the people with two pre-pandemic scans didn't change much over time. (You can see the distribution here is centered at 0). Of course, some got younger and some got older, but on average there was no change.

The researchers identified about 1000 healthy people who had two MRI scans in the cohort. 432 had one scan before the pandemic started and one after. A control group of 564 participants had two pre-pandemic scans.

BAGs are pretty stable over time. If your BAG today is 5 years, your BAG 10 years from now stays about 10 years... unless something causes your brain to start aging faster. Something... like a pandemic?

If someone says your brain age gap is very high, you can reply no, that's not my BAG baby.

Of course, some brains look younger than the calendar age of the body they are in (call it the Paul Rudd effect), and some look older. The difference between your brain age and your calendar age is your "Brain Age Gap" or BAG.

Researchers used MRI scans from more than 15,000 healthy individuals of various ages from the UK biobank cohort to teach a computer how to estimate age from pictures of a brain - just like the carnival barker. And the computer got pretty good at it, as you can see here.

So... what is brain age? Well, think of a carnival barker playing "guess your age". They use various clues - how you look, the clothes you wear, your hairstyle, etc to predict your age. And they are usually pretty good at it!

Scary headline comes from this study, appearing in Nature Communications.
dx.doi.org/10.1038/s414...

The COVID pandemic AGED your brain by 5.5 months, on average, according to a new study. That... sounds bad. But what does "brain age" mean? And what does a brain that is aging more rapidly mean to you?
Using what's left of my brain to break down this new study.
(1/N)

Longer form / a bit more detail in my @medscape column here: buff.ly/dEVy1LJ

/thread

Regardless, we should be keep a (bloodshot) eye on this syndrome and on the lookout for it. Fortunately, it resolves with abstinence from cannabis. (I am also told that hot showers can relieve the symptoms in a pinch).