The study is called "Phosphodiesterase Type 5 Inhibitors in Men With
Erectile Dysfunction and the Risk of Alzheimer Disease" and published in "Neurology", for reference. It's open access, link: https://doi.org/10.1212/WNL.0000000000209131
The paper mentions neuroprotective effects, but it has been known for a while that nearly all types of PDE inhibitor can boost cognitive function, which has led to some interest in them as nootropics: https://pubmed.ncbi.nlm.nih.gov/25464010/
So, yeah, if I fancied myself at risk for dementia, I don't think it would be unwise to take viagra or sildenafil as a precautionary neuroprotective measure.
From the same paper, there's some indication that its cognitive effects might be more potent in women, as "[s]everal studies have suggested that sex hormones may influence the effects of sildenafil on the brain. Female mice performed significantly better than males after sildenafil treatment following HI insult, which suggests a sex-dependent effect of sildenafil (Engels et al., 2017). The underlying mechanism might be related to the relationship between sex hormones and the NO/cGMP pathway."
>> Covariates. We adjusted for an extensive number of covariates all measured before or at cohort entry. These included risk factors for AD and potential confounders associated with PDE5I exposure and AD. [...]
The parent post makes a good point that it’s very hard to do this kind of research well. We should default to skepticism. There is a replication crisis on right now.
That means looking at methods, discussing confounding factors and how they were and weren't handled correctly, and what alternatives could have been employed.
There's a similar form of dismissive, passive skepticism that says: science has problems, so it's not even worth looking harder.
Note: I'm assuming good faith on part of parent, so not pointing fingers. But it is a thing I've seen on HN, especially re: biology.
I will comment though: Passive skepticism is important too. At this stage, the bigger problem is treating one study outcome as if it were fact. Dismissing established, well-replicated science is, of course, a problem as well, but at least from what I've seen, the much bigger problem is that you have one correlational study. Popular media runs with it. People make products based on it. The underlying science is nonsense.
The good news is that it's also possible to solve. There is constant progress in science, of course, but if we ignore all science from the past 20 years, we're still left with pretty good science (at least for the level of policy-making and personal decision-making). Simply ignoring anything recent solves the hype problem. And for all the anti-vaxxers and flat earthers, those are still minorities since recognizing established science is actually not especially hard.
> [...] but if we ignore all science from the past 20 years, we're still left with pretty good science
But what if the people of 20 years ago had made that same choice? And the people 20 years before then? Etc.
It's not a tenable long-term position.
> Popular media runs with it. People make products based on it. The underlying science is nonsense.
This has always been the case, though. A majority of people are dumb and/or lazy. Consequently, the quickest way to make a buck off them is the above.
But that trash science gets popularly communicated doesn't opine on the advancement of the academic practice.
> And for all the anti-vaxxers and flat earthers, those are still minorities since recognizing established science is actually not especially hard.
This feels like something we degree pretty strongly on.
(1) I don't think it should ever be easy to tell bad science, (2) I certainly don't think established science should hold an especially privileged place (heliocentrism!), & (3) I do think that the anti-vaxxers and flat earthers deserve a place in any true scientific practices (there's a myriad of ways they generally demonstrate their ineptitude, but ideas should not be verboten).
It's a perfectly tenable long-term position. You're missing two points:
1) People aren't uniform. I read all the papers in my narrow field and evaluate them. On the other hand, in 99% of fields, you and I are a popular audience. We should rely on established science. And in my field, you should also not rely on hot-off-the-press because most of it is nonsense.
2) Science becomes established -- over decades -- when you have multiple corroborating results, replicated, with multiple methodologies. We know the earth isn't flat because we e.g. sent a man to the moon. That's a very different standard of knowledge than Viagra and Alzheimers. Before acting on this, let experts in this field do their thing for another decade and understand the pathways, do an RCT, etc. At that point, it will be 20-year-old fact. Or perhaps it will turn out to be a correlation / causation issue, and you'll never hear about it again. Either way.
I'd say the method that science becomes established is one of the problems, because a big chunk (50%?) of that process is non-scientific (political people processses).
I'd feel a lot better if "established" meant something more like well-replicated (with an economic/academic model to support that).
Both have places, but science must be in #2 to work at all. That is the point of science.
One of the critical parts of this mindset is separating criticism of work, quality of work, and the individual. Indeed, the more significant the science, the more it needs criticism. There is little (and probably even a negative) correlation between the quality of science and the quantity of criticism.
If I list out the limitations of your work in a blog post, that is not, should not, and cannot be read as a condemnation of your work, and especially not of you as an individual.
Indeed, generally, what that means is I took an interest in your work, found it compelling enough to do a deep dive, and I wrote a blog post because I'm trying to figure out next steps.
There is a pipeline from speculation to hypothesis to theory to fact, and it RELIES on people doing their best to invalidate a piece of work, understand methodological limitations, find alternative explanations, and otherwise poke holes. Once those holes are filled, and there are no more criticisms, you have trustworthy knowledge.
PLEASE attack my work (so long as you do it honestly and correctly; not unhinged emotional attacks). It makes my work better.
If the comment was along the lines of "I've read the paper and think it has some serious problems like x, y and z" then you'd be right.
But this is just someone who's read the title of a BBC article about the paper and basically saying "yeah but science is hard". We know it's hard. That's why we don't all have publications in peer-reviewed journals. This isn't specific to this study. You think published authors in the field don't know this?
I don't think the audience for the comment was "published authors in the field" but "random people in a web forum" who make comments like yours ("Imagine telling someone you made a website and they're like 'cool, but did you even make sure it has the little green padlock?'")
In that context, it's often helpful to remind people that:
- Correlation is not causation
- It takes many replicated results to go from hypothesis to theory
(Which is quite different from "science is hard"). This is doubly-true with the current level of hype and grandstanding in science where primary and secondary sources are often clickbaity and misleading.
I was thinking along similar lines: sildenafil (the active compound in viagra) was originally researched as a hypertension medication. The link between hypertension and dementia is well-established, and hypertension is also extremely common and relatively underdiagnosed.
The problem with a lot modern science is that you're dealing with a virtually infinite numbers of variables both environmentally, behaviourally and genetically.
Short of having a thousand identical twins locked up in a room from birth you're swimming against a very strong tide. Long gone are the days when science was as simple as castrating a rooster and grafting his balls back: https://en.wikipedia.org/wiki/Arnold_Adolph_Berthold
> Wouldn't taking these kind of factors into account be quite basic part of the analysis?
They acknowledge that they are just looking at the number of prescriptions and that the research doesn't show that the drugs themselves were reducing people's risk.
It could equally be the amount of sex that is reducing the risk.
Maybe the brain get's worse at clearing stuff out as your blood vessels age and viagra is opening them up? Cardio, weight lifting, HIIT, sauna, healthy balanced diet, yoga, inversions, beetroot juice, citrulline malate, etc. could all be worthy of investigation ;-)
Physical activity and a healthy lifestyle positively impact the body in any case. I would even add psychological well-being and, so to speak, harmony with oneself
Yes, sex is just awesome in every sense. Regular sex lowers the level of stress in the body and increases the level of oxytocin. As a result, people feel more motivated to work and experience greater satisfaction from their work as soon as the stress level decreases. It also leads to increased life expectancy, so people have more time to work and more time to have sex - it's a complete cycle
> people feel more motivated to work and experience greater satisfaction from their work
It kinda weirded me out to see work/productivity being listed in regards to benefits of sex. Yeah, it might help but this way of thinking sounds absolutely horrendous.
Think less "I'm working 60 hours a week for my ignorant overlord and now I'm keen to do more!" and more "I'm really struggling to find purpose and enjoy the job that I have enjoyed in the past; now I'm feeling more content with general life and I'm positive about getting back on track at work."
OP listed some untypical benefits that come with sex - I think we are all aware of the typical benefits. He/she didn't say "these are the reasons you should have sex"
Shoehorning productivity as a benefit to things in life that should have nothing to do with productivity. It reeks of viewing activities in life as means to increase productive output, which is... Sad.
Can someone explain how the study could successfully adjust for men in relationships taking this kind of med vs (especially) long time single men who don't?
Especially in older men, these groups can look nothing like each other.
It's a vasodilator, which is means it also reduces blood pressure (that was the drug's original purpose).
So it's conceivable that it could clear a wider exit pathway for amyloid plaques and other garbage that accumulates in the brain.
It's also why a significant fraction of men who take it develop headaches so painful that sex is the last thing on their mind. Welcome to vasodilators.
Oh and if you already take nitroglycerin for cardiac angina, you can't take viagra because you get twice the headache -- right before you pass out because your blood pressure crashed.
A study for tadalafil or sildenafil would probably show the same effects. Not because of common mechanism that prevents Alzheimer, but because such studies would probably plagued by the same methodological problems.
Please let's make a downvote free thread for throwing jokes a round on this topic. We need this freedom for such a topic trending on HN.
There is so much low hanging fruit and we're all thinking of several I suspect. My initial thought was in the lane of 'drug is affecting one more head than intended', but it's missing some refinement I'll admit
And you're welcome to find it funny. But I don't welcome a long thread of Reddit-style stupid jokes about this here. If I wanted that I'd go to Reddit.
Yea HN is great and the majority of comments and discussions are the best I know of online. Especially the deep expertise popping up unexpectedly on different topics <3
And yea, I can live with this new subjective experience that some people here take thing a little too seriously also. One sine thread in a viagra post for some sillyness is too much. I find that silly in it self. But fine, lesson learned moving on.
PS. Today is Friday and it is my duty to shower at-least one of my colleagues with a new dad joke. I take this duty quite seriously and won't let anyone down.
Childish mindset is more likely to innovate though. For hacking ones environment, growing up makes one ineffective. Then again, so does low effort Dopamin bombarding content consumption. Then again it creates a nice little pocket universe meta discussion.
