Could be that reading makes you less likely to expose to dangers that could kill you by entertaining you in a safer environment, could be that reading makes you

Could be that reading makes you less likely to expose to dangers that could kill you by entertaining you in a safer environment, could be that reading makes you have better decisions for your health, could be that your brain has more neural connections that can be used redundantly to mask Alzheimer’s. And what you mentioned is also combined with the above, and uncountable other relationships, causality going both ways.