Old Crib Mattress - SIDS?

woohoo02

I was talking to a co-worker of mine today about baby stuff, and she told me about how using old crib mattresses can increase the risk of SIDS. We were planning on using DS' old crib mattress for this LO. He's 8 now, used the mattress for about 16 months, then we packed it away, sealed in its protective cover. It doesn't smell like mold and it's not dirty or anything.

I haven't heard about the link between old mattresses and SIDS before, and I was curious as to what, if anything you all have heard about it. If so, are you getting a new mattress or using your old one?

If anything, perhaps we'd just purchase a new cover for the mattress, but even that looks and smells fine.