Cat Ownership = Healthier Heart

I'm severely allergic to cat hair. Owning a cat would probably make my life shorter.
And in response to MoonCake's comment, I don't think it quite works that way. I grew up with cats and it hasn't made me any less allergic.
People with dustmite allergies live in the constant presence of dustmites (there is no escaping them, they're EVERYWHERE), and as far as we know, this doesn't reduce their allergic reactions.
I suppose we could do an experiment, but there would be no way of having a control no-dustmite group unless we locked those subjects naked in a plastic bubble with no fabric.

This study was biased because it didn't include dogs. I would expect to find an even better health effect from dogs, actually. Sure, you can pet them and have companionship (like with cats)... but dogs will also get you off your butt and outside because they need exercise... and therefore you get exercise, too.

And is it really healthier to give love to something that couldn't care less if you didn't come home one night? Dogs are always glad to see you. Cats? Not so much.

on another end of the spectrum, it could have to do with the fact that animals bring bacteria and allergens into the home. when they do this, their owners are exposed and are forced to react either by illness or allergy-related ailment. either way, your immune system has to boost itself back to health and it creates antibodies to protect you from future outbreaks. it's the same concept as a flu shot, except without so many needles and band-aids. with an over-all boost of immunity, you tend to ward off more illness, which improves your over-all health, and enables you to have a longer life-expectancy. but this is just my take on it.

does this include the parasite in their feces? food for thought

We used to have great biodiversity where I live but feral & domestic cats have killed everything. I really miss all the wildlife. I'm sure if all the wonderful creatures were still around to look at, I'd be healthier too. But no, all gone, killed by cats.