Interesting research but very early stages. There's a good chance that this isn't really specific to bikes, but more generally applies to the benefits of people enjoying hobbies and a good quality of life translating into a better psychological state, which is known to affect health outcomes in a myriad of ways specially related to brain function and hormones.

Interestingly, the data also shows that mixed-walking is associated with reduced dementia as well... and I find it a bit confusing that the authors are lumping driving and public transit together in the nonactive category because public transit usually involves a good deal of walking too without people categorizing it as a walking mode of transport.

Beyond separating public transit from driving, I think major factors to control for are: 1) how often these non-commute activities happen; and 2) what's the stress level of that transportation mode. With those three things in mind I think it would clarify why would walking be associated with worst outcomes than nonactive...

All that cheery pro cycling stuff having been said, cyclists with the APOE4 gene did not see the same benefit. APOE4 is a known risk factor for Alzheimer’s. Researchers also acknowledged that while the study adjusted for age and education, its findings are purely observational. It’s not establishing a 100 percent definitive pattern of cause-and-effect.

Also important, is most people suffering from dementia don't recognize what's happening.

However, they'll still respond to symptoms by starting to avoid activities that give them difficulty. Even if they're not consciously understanding why they're not enjoying a hobby anymore.

So I wouldn't be surprised if further studies show that as a cyclist starts to develop dementia, the loss of ability in navigating their surroundings causes them to stop riding as much. If that's true, then that accounts for why cyclists would have lower rates of dementia...

Because the ones developing dementia, stop being cyclists.

Quick edit:

What would be really interesting is looking at rates for elderly cyclists who have switched to a stationary bike, and if symptoms were starting to manifest before or after the switch.

It's done wonders for my legs. My brain, on the other hand...

Wait, this is a recent article? I (and Wikipedia) thought Vice has stopped publishing articles? (I aslo dimly remember them being bought by someone terrible but looks like I'm confusing that with something else)

I loved bicycling as a kid. I don't think I can find an under 100 dollar bike these days though.

Why is Vice still a publication?

Strange story.

as a hobby

So drive for fun rather than just as a mode of transport?

Just remember to wear your helmet.

No, thanks.

Also, people cycle a lot in the Netherlands and it has one of the world's highest rates of dementia 🤷‍♂️