box spring vs slats?

For old people with back problems, would a box spring be better than slats?
Are all slats the same or should I look for something specific?
Are low profile box springs worse than regular? It’s harder for old people to get into a higher bed. But again, the back pain is more important.
Assuming, box springs are better, where should I buy box springs? I see some zenith ones on amazon that come in a box. Are those terrible? They seem pretty low priced. Should I look for prebuilt ones locally? I kinda know where to start at looking for mattress reviews, but dont know if there is something similar for box springs.

Hi sdmat.
When picking out your foundation, check with the mattress manufacturer to see the requirements first and foremost.

Assuming the requirements are like most – a flat, sturdy base will do (platform, foundation, adjustable bed, slatted base with minimal gap).

To answer a few of your other questions:
Low profile foundations are just as supportive as standard height foundations.

If the Zenith foundation meets the requirements of the mattress you purchase (ask about the gap between slats), it will probably be fine.