The risk of sudden incap rises with age, there are lots of factors but you cannot remove age from the equation. I think there does need to be an age limit, but don't know what it should be.

That age has probably increased since the 1950's as people on average live healthier lives.

I would be OK with slightly more stringent requirements for BMI, blood pressure, etc after age 50 or 60... those are cheap and easy to measure and also easy to correlate to specific statistics for stroke, etc. That would mitigate the age associated risk.