Indoor cats have lifespans multiple times that of outdoor cats, so I think the alternative has negative effects on health, too.
The oldest got to 8 yrs.
Most died of organ failures, one from a genetic illness and another one never came back.
The Organ failures were probably from rat poison... So, the outside killed them
[0] https://pets.webmd.com/cats/features/should-you-have-an-indo...